CN110688696B - Method and device for determining parameters of a tunnel support structure - Google Patents

Abstract

An embodiment of the present invention provides a parameter determination method and device for a tunnel support structure, the method comprising: obtaining the setting values and the tunnel model of the parameter items of the tunnel support structure; according to the setting values of the parameter items and the tunnel model , to calculate the bearing load of the tunnel support structure; according to the set value of the parameter item, calculate the elastic modulus of the equivalent space shell of the tunnel support structure; use the finite element model to simulate the tunnel support structure, and the elastic modulus As the material parameters of the simulated tunnel support structure and the bearing load is applied, the internal force of the simulated tunnel support structure is calculated; according to the calculated internal force and material strength, the safety of the tunnel support structure is verified, and the corresponding verification results are obtained; according to the verification As a result, the values of the parameter items are adjusted so that the truss structure is both safe and economical. The invention is applicable to the supporting structure which can provide relatively large bearing capacity, realizes that the next process can be carried out without spraying concrete within a certain working range, and improves the construction efficiency.

Description

Method and device for determining parameters of a tunnel support structure

technical field

The invention relates to tunnel construction and safety technology, in particular to a method and device for determining parameters of a tunnel support structure.

Background technique

At present, the initial support of the tunnel is basically based on the joint action of grid steel frame, section steel steel frame with spray mix, anchor rod and steel mesh. The unit of steel frame is truss, and the longitudinal spacing is generally 0.5-1.5m/trunk. Due to its discreteness along the longitudinal direction and the weak bearing capacity of the grid steel frame itself, the ability of the steel frame to bear the load of the surrounding rock is weak before the shotcrete, and the next process must be carried out after the shotcrete.

Correspondingly, the calculation method of the initial support is based on the grid steel frame and the section steel frame, specifically including: calculation of surrounding rock pressure; distribution of the load ratio of the initial support in stages according to experience; use of finite element software to carry out load-structure model Calculate and obtain the internal force of the structure, that is, the bending moment M, the axial force N, and the shear force Q; in the steel frame installation stage, the steel structure tension bending and compression bending members are used for strength calculation; the reinforced concrete structure calculation formula is used in the post-spraying stage , the grid steel frame and section steel frame are regarded as the stressed steel in the reinforced concrete structure for calculation, and the safety factor and crack width of the structure are checked. However, this calculation method is aimed at support structures with longitudinal discreteness and weak self-bearing capacity. It is suitable for the support structure of the steel frame and the sprayed concrete after spraying concrete, and is not suitable for the support structure that can provide a larger load before spraying concrete. Supporting structures with load-carrying capacity.

Contents of the invention

The embodiment of the present invention provides a method and device for determining the parameters of a tunnel support structure to solve the problem that the support structure calculation method in the prior art cannot be applied to a support structure that can provide a larger bearing capacity before spraying concrete .

According to a first aspect of an embodiment of the present invention, a method for determining parameters of a tunnel support structure is provided, including:

Obtaining the setting values of the parameter items of the tunnel support structure and the tunnel model; wherein, the tunnel support structure includes at least two mutually assembled trusses, and the trusses include: a stressed rod body and a connector connecting the rod bodies;

Calculate the bearing load of the tunnel support structure according to the set values of the parameter items and the tunnel model;

Calculate the elastic modulus of the equivalent space shell of the tunnel support structure according to the set value of the parameter item;

The finite element model is used to simulate the tunnel support structure, and the elastic modulus is used as the material parameter of the simulated tunnel support structure and the bearing load is applied to calculate the internal force of the simulated tunnel support structure;

According to the calculated internal force and the material strength of the truss, the safety of the tunnel support structure is verified, and the corresponding verification results are obtained;

According to the verification result, adjust the value of the parameter item.

According to a second aspect of an embodiment of the present invention, a device for determining parameters of a tunnel support structure is provided, including:

The first acquisition module is used to acquire the setting values of the parameter items of the tunnel support structure and the tunnel model; wherein, the tunnel support structure includes at least two mutually assembled trusses, and the trusses include: a stressed rod body and a connector connecting the rod body ;

The first calculation module is used to calculate the bearing load of the tunnel support structure according to the set value of the parameter item and the tunnel model;

The second calculation module is used to calculate the elastic modulus of the equivalent space shell of the tunnel support structure according to the set value of the parameter item;

The third calculation module is used for simulating the tunnel support structure by using the finite element model, using the elastic modulus as the material parameter of the simulated tunnel support structure and applying a bearing load, and calculating the internal force of the simulated tunnel support structure;

The verification module is used to verify the safety of the tunnel support structure according to the calculated internal force and the material strength of the truss, and obtain corresponding verification results;

The adjustment module is used to adjust the value of the parameter item according to the verification result.

The method and device for determining the parameters of the tunnel support structure provided in the embodiment of the present invention can realize the parameter design of the support structure that can provide a large load-bearing capacity before the sprayed concrete, and ensure that the designed support structure can meet the construction requirements. Safe, because the supporting structure can provide a large bearing capacity before spraying concrete, it can realize the next process without spraying concrete within a certain working range, which improves the construction efficiency.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 shows the schematic flow chart of the parameter determination method of the tunnel support structure of the embodiment of the present invention;

Fig. 2 represents the construction schematic diagram of the tunnel support structure of the embodiment of the present invention;

Fig. 3 shows the schematic diagram of the truss structure of the embodiment of the present invention;

Fig. 4 shows a schematic diagram of a module structure of a device for determining parameters of a tunnel support structure according to an embodiment of the present invention.

Detailed ways

In the process of realizing the present invention, the inventors found that the current structural parameter design method of the space truss is aimed at the support structure with longitudinal discreteness and weak self-bearing capacity, and is suitable for the overall load bearing of the steel frame after spray concrete and spray concrete The support structure is not suitable for the support structure that can provide a large bearing capacity before spraying concrete.

In view of the above problems, the embodiment of the present invention provides a method for determining the parameters of the tunnel support structure, which can realize the parameter design of the support structure that can provide a large bearing capacity before spraying concrete, and ensure that the designed support structure It can meet the construction safety, because the supporting structure can provide a large bearing capacity before spraying concrete, and the next process can be carried out without spraying concrete within a certain working range, which improves the construction efficiency.

The solutions in the embodiments of the present invention can be realized by using various computer languages, for example, the object-oriented programming language Java and the literal translation scripting language JavaScript.

In order to make the technical solutions and advantages in the embodiments of the present invention clearer, the exemplary embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, and Not an exhaustive list of all embodiments. It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

The embodiment of the present invention provides a method for determining parameters of a tunnel support structure, as shown in Figure 1, the method includes the following steps:

Step 11: Obtain the setting values of the parameter items of the tunnel support structure and the tunnel model; wherein, the tunnel support structure includes at least two pieces of mutually assembled trusses, and the trusses include: stressed rods and connectors connecting the rods.

Among them, in the embodiment of the present invention, the parameter items of the tunnel support structure include but are not limited to: the longitudinal support length of each space steel truss, the number of steel bars (pipes) in the longitudinal section of the space steel truss per linear meter (one-sided ), the thickness of the initial support, the material thickness of the rod body (such as the diameter of the steel bar, the wall thickness of the steel pipe), the diameter of the connecting piece and the circumferential spacing of the connecting piece, etc. The setting values of these parameters can be parameter experience values or design values. The tunnel model of the embodiment of the present invention is used to simulate the actual tunnel conditions, and is related to tunnel engineering geology, hydrogeological conditions, and existing tunnel design and construction experience. related parameters.

Optionally, as shown in FIG. 2 , the tunnel support structure in the embodiment of the present invention includes at least two mutually assembled trusses 1 . Among them, during the construction process, the support structure can be assembled along the extension direction of the tunnel, and the assembled support structure can be completely wrapped with shotcrete inside the support structure to form a lining structure to support the tunnel. Since the truss 1 has strong rigidity, it can bear the relaxation load of the surrounding rock during the construction period, and the next process can be carried out without spraying concrete immediately. In order to speed up the excavation progress, the sprayed concrete is delayed within a certain distance from the operation face 3 , the load-bearing structure can only use the space steel truss structure as the initial support. Wherein, a piece of truss can include at least two prefabricated units, the prefabricated units are prefabricated in sections according to the shape of the tunnel section, at least two prefabricated units are assembled into a shape suitable for the shape of the tunnel section, such as circular, rectangular, horseshoe, polygonal, etc. In this embodiment, the prefabricated unit is adapted to the shape of the tunnel section, and this embodiment does not limit the specific shape assembled.

Among them, the whole ring truss can also be called a piece, and at least two prefabricated units are assembled in the piece to form a linear or arc-shaped structure. As shown in Figure 3, a piece of prefabricated components is formed by assembling three prefabricated units. It is worth pointing out that, The embodiment of the present invention does not limit the number of prefabricated units contained in a prefabricated component, and those skilled in the art can determine the number of prefabricated units contained in a prefabricated component according to actual needs. Wherein, the prefabricated unit includes an outer ring structure formed by uniformly arranging a plurality of rod bodies 111 , an inner ring structure formed by a plurality of rod bodies 111 evenly arranged, and a connecting piece 112 . Since the rods 111 on the outer ring structure and the inner ring structure are evenly arranged, it can ensure that the force on the outer ring structure and the inner ring structure is uniform. Among them, the adjacent rod bodies 111 on the outer ring structure are connected by the connecting piece 112, the adjacent rod bodies 111 on the inner ring structure are connected by the connecting piece 112, and the rod bodies 111 on the outer ring structure and the inner ring structure are connected. Connection via connection 112 is also possible. The smallest shape unit surrounded by the rod body 111 of the outer ring structure and the inner ring structure through the connecting piece 112 is a triangle, that is to say, the connection between the rod body 111 on the outer ring structure and the inner ring structure and the connecting piece 112 can form a plurality of triangles. Other shapes are formed, so that the support strength of the prefabricated components can be further improved through the triangular stable structure.

Step 12: Calculate the bearing load of the tunnel support structure according to the set values of the parameter items and the tunnel model.

Wherein, the bearing load in this embodiment mainly includes: self-weight load and external load. Among them, the external load mainly includes: formation resistance and surrounding rock pressure.

Step 13: Calculate the elastic modulus of the equivalent space shell of the tunnel support structure according to the set values of the parameter items.

In this embodiment, the tunnel support structure is equivalent to a space shell structure, and the elastic modulus of the equivalent space shell is calculated by using the set values of various parameter items of the tunnel support structure. This method can better By simulating the tunnel support structure, the calculated elastic modulus can be equivalent to the elastic modulus of the tunnel support structure as a whole.

Step 14: Use the finite element model to simulate the tunnel support structure, use the elastic modulus as the material parameter of the simulated tunnel support structure and apply a bearing load, and calculate the internal force of the simulated tunnel support structure.

In this embodiment, the bearing load calculated in step 12, the elastic modulus and material parameters calculated in step 13 are used as the input of the finite element algorithm (finite element software) to calculate the internal force parameters of the tunnel support structure to obtain accurate internal force parameters. Among them, the internal force parameters include: bending moment, axial force and shear force, etc. Among them, the finite element calculation software includes but not limited to: Midas, Abaqus, Ansys, etc.

Step 15: According to the calculated internal force and the material strength of the truss, verify the safety of the tunnel support structure, and obtain corresponding verification results.

The safety of the tunnel support structure is verified by the calculated internal force parameters to determine whether the tunnel support structure designed with the set values of each parameter item meets the safety requirements.

Step 16: Adjust the value of the parameter item according to the verification result.

If the verification result indicates that the security requirements are not met, it is necessary to adjust the values of each parameter item and continue the verification to determine the parameter item that meets the security. If the verification results indicate that the safety requirements are met, and the safety requirements are exceeded, it is necessary to adjust the values of each parameter item to continue the verification, so as to save materials and reduce costs.

In some embodiments of the present invention, the longitudinal support length L of each piece of space steel truss, the number (one side) n of reinforcing bars (pipes) in the longitudinal section of each space steel truss, and the thickness of the initial support are preliminarily determined. h and other construction parameters, these parameter items can take industry experience values. For other parameter items, a set value can be assumed, such as the diameter (thickness) of the rod body material, for structural mechanics analysis to check whether the structural safety factor meets the requirements. Through the trial calculation of these parameter items, the value of the parameter item that meets the security requirements is obtained.

Wherein, step 12 includes: calculating the self-weight load and external load of the tunnel support structure. Specifically, it includes: calculating the self-weight load of the tunnel support structure according to the set values of the parameter items; calculating the external load of the tunnel support structure according to the tunnel model; determining the self-weight load and external load as the bearing capacity of the tunnel support structure force load. The calculation method of bearing load will be further explained in conjunction with specific examples below.

1. Calculation of self-weight load

Wherein, according to the setting value of the parameter item, the step of calculating the self-weight load of the tunnel support structure includes: adopting the first formula to calculate the self-weight load f of the tunnel support structure; wherein, the first formula is:

f=γ ₁ V ₁ ;

Among them, _γ1 represents the material weight of the tunnel support structure, and _V1 represents the volume of the calculation unit.

2. Calculation of external load

According to the tunnel model, the step of calculating the external load of the tunnel support structure includes at least one of the following: according to the tunnel model and geological parameters, calculating the formation resistance borne by the tunnel support structure; according to the tunnel model and geological parameters, calculating the tunnel support The surrounding rock pressure borne by the structure, wherein the calculated surrounding rock pressure is the theoretical surrounding rock pressure value, and the surrounding rock pressure can be corrected by the correction parameters to obtain a value close to the actual surrounding rock pressure.

1. Calculation of formation resistance

According to the tunnel model and geological parameters, the steps of calculating the formation resistance of the tunnel support structure include: determining the formation resistance coefficient of the tunnel model according to the geological parameters of the tunnel surrounding rock; using the Winkel assumption algorithm to combine the tunnel surrounding rock and The tunnel model is equivalent to a spring group; the formation resistance coefficient is assigned to the spring group to calculate the formation resistance borne by the tunnel support structure. Specifically, in the chain rod method, the stratum resistance is simulated by stratum springs. Using the Winkel assumption, the effect of the surrounding rock and the tunnel model is simplified into a series of springs, and the above-mentioned stratum resistance coefficients are given to the springs to calculate the tunnel support. Ground resistance of the protective structure. The formation resistance coefficient is determined according to the soil layer conditions and calculated according to the Winkel assumption. In the calculation, the spring in tension is eliminated.

2. Calculation of surrounding rock pressure

According to the tunnel model and geological parameters, the step of calculating the surrounding rock pressure borne by the tunnel support structure includes: respectively calculating the vertical and horizontal uniform pressure of the surrounding rock borne by the tunnel support structure according to the tunnel model and geological parameters. Among them, the calculation methods of vertical uniform pressure and horizontal uniform pressure under tunnel model are different. The type of tunnel model is different, the calculation method of vertical uniform pressure is different, and the calculation method of horizontal uniform pressure is also different. Wherein, after calculating the surrounding rock pressure, it also includes: adjusting the surrounding rock pressure according to the load factor, wherein the load factor is the proportion of the surrounding rock load borne by the tunnel support structure in an actual project. In the following, this embodiment will be further described in combination with the calculation of surrounding rock pressure for deep tunnels and shallow tunnels.

2-1. Conditions of deep buried tunnels

The case of a deeply buried tunnel refers to a case where the distance between the tunnel vault and the ground surface exceeds a certain value, and in this embodiment refers to a case other than the case of a shallow buried tunnel. For the calculation of the vertical uniform pressure: when the tunnel model is a deep tunnel, the second formula is used to calculate the vertical uniform pressure q of the surrounding rock borne by the tunnel support structure (the unit can be kPa); where, the second The formula is:

q＝γ ₂ h _q

Wherein, h _q =first constant×2 ^S-1 w, w=second constant+i(B-third constant);

Among them, γ ₂ represents the weight of the surrounding rock (the unit can be kN/m ³ ), h _q represents the calculated height of the surrounding rock collapse arch (the unit can be m), S represents the grade of the surrounding rock, w represents the width influence coefficient, and B represents the tunnel Excavation width (the unit can be m), and i represents the increase or decrease rate of surrounding rock pressure per unit increase in excavation width.

Optionally, the first constant may be 0.45, the second constant may be 1, and the third constant may be 5. Correspondingly, h _q =0.45×2 ^s-1 w, w=1+i(B-5). Among them, when B<5m, take i=0.2, and when B≥5m, take i=0.1.

For the calculation of horizontal uniform pressure: when the tunnel model is a deep-buried tunnel, the product of the vertical uniform pressure of the surrounding rock borne by the tunnel support structure and a specific coefficient is determined as the horizontal uniform pressure of the surrounding rock borne by the tunnel support structure Distribution pressure, where the value of a certain coefficient is related to the grade of the surrounding rock. For example, the horizontal uniform pressure in this case can be determined from Table 1 below:

Table 1

Surrounding rock level Ⅰ～Ⅱ III IV Ⅴ Horizontal uniform pressure 0 <0.15q (0.15～0.30)q (0.30～0.50)q

2-2. Conditions of shallow buried tunnels

Shallow buried tunnel refers to the case where the distance between the centerline, top or bottom of the tunnel and the ground surface is lower than a certain value, such as the case where the buried depth of the tunnel is greater than h _q and less than 2.5h _q .

For the calculation of the vertical uniform pressure: when the tunnel model is a shallow tunnel, the third formula is used to calculate the vertical uniform pressure q of the surrounding rock borne by the tunnel support structure; where the third formula is:

in,

γ ₂ represents the weight of the surrounding rock (the unit can be kN/m ³ ), h ₂ represents the height of the tunnel top from the ground (the unit can be m), λ represents the lateral pressure coefficient, and θ represents the friction angle on both sides of the tunnel top (the unit can be is °, generally take the empirical value), B represents the tunnel excavation width or the tunnel span (the unit can be m), β represents the rupture angle at the maximum thrust (the unit can be °), Indicates the calculated friction angle of the surrounding rock (the unit can be °).

Optionally, the fourth constant can be 1, the fifth constant can be 1, and the sixth constant can be 1. Correspondingly,

For the calculation of the horizontal uniform pressure: when the tunnel model is a shallow tunnel, the fourth formula is used to calculate the horizontal uniform pressure e _i of the surrounding rock borne by the tunnel support structure; where the fourth formula is:

e _i =γ ₂ h _i λ

Among them, γ ₂ represents the weight of the surrounding rock (the unit can be kN/m ³ ), h _i represents the distance from any point in the tunnel to the ground (the unit can be m), and λ represents the lateral pressure coefficient.

Furthermore, the surrounding rock pressure calculated above is the maximum relaxation load borne by the tunnel lining. However, considering the supporting effects of the surrounding rock in front of the tunnel face, the primary support at the rear and the secondary lining, there is a certain spatial effect. The actual construction During the process, the space steel truss support structure will not bear such a large load, so in the design, the above load is reduced. Specifically, after calculating the surrounding rock pressure, it also includes: adjusting the surrounding rock pressure according to the load coefficient, wherein the load coefficient is the ratio of the load value passed in the trial calculation to the maximum load value. For example, assuming that the surrounding rock load calculated according to the above buried depth is q, q'=μq, where μ represents the load factor, which is the ratio of the load value passed in the trial calculation to the maximum load value, and q' represents the load applied to the tunnel support. The relaxation load on the protective structure (space steel truss).

It is worth pointing out that in the stage of steel frame erection and sprayed concrete stage, different load coefficients μ are used to adjust the load acting on the tunnel support structure, so as to obtain the load in line with the actual force condition of the support structure.

The calculation method of bearing load in step 12 under different scenarios has been introduced above, and this embodiment will further illustrate an example of calculating the elastic modulus of the tunnel support structure in step 13 in combination with application scenarios.

Specifically, taking the circular section structural lining of the underground excavation tunnel shown in Figure 3 as an example, the structural stress is mainly eccentric compression, and according to the equivalent principle of tension and compression stiffness, the steel frame erection stage and the shotcrete stage The supporting structure is equivalent to a space shell structure with a certain thickness.

In the stage of steel frame erection, EA=E _g (A _g +A' _g ), A=Lh, correspondingly, step 13 includes: using the fifth formula to calculate the elastic modulus of the equivalent space shell of the tunnel support structure Quantity E; Wherein, the fifth formula is:

Among them, A _g and A' _g represent the cross-sectional area of the rod body in the tension and compression zone (the unit can be m ² ), E _g represents the elastic modulus of the rod body, and L represents the effective longitudinal length of a truss in the tunnel support structure, h represents the thickness of the equivalent space shell.

Among them, in the case that the rod body is a steel bar, Among them, n represents the number of rods contained in the longitudinal section of a truss, and D represents the diameter of the steel bar.

In the case that the rod body is a steel pipe, n represents the number of rods contained in the longitudinal section of a truss, D represents the diameter of the steel pipe, and t represents the wall thickness of the steel pipe.

The calculation of the elastic modulus at the erection stage of the steel frame is introduced above. For the shotcrete stage, according to the existing design experience, at this stage, the contribution of the stiffness of the steel to the equivalent stiffness of the section is almost negligible. Therefore, at this stage, the stiffness of the shotcrete can be directly used as the stiffness of the equivalent section.

The calculation of the internal force parameters is based on the calculation results of the above-mentioned bearing load and the elastic modulus of the equivalent space shell. According to the basic principles of elastic mechanics, the problem of solving the internal force of the tunnel section can be simplified as a plane strain problem in the embodiment of the present invention. . Using the finite element method, the internal forces (bending moment M, axial force N and shear force Q) of the support structure in the stage of erecting the steel frame and the stage of sprayed concrete are calculated respectively.

After obtaining the internal force parameters, the safety of the tunnel support structure can be verified based on the internal force parameters. The following embodiments of the present invention will verify the safety in combination with different construction stages, so as to obtain appropriate design values of structural parameters.

Specifically, step 15 includes: at the stage of erecting the truss, use the sixth formula to calculate the corresponding verification result; when the verification result is that the safety factor is greater than or equal to the first value, determine that the tension and compression safety of the tunnel support structure satisfies Require. Assuming that the first value is 2.4, then when K is greater than or equal to 2.4, the value of the parameter item of the tunnel support structure meets the safety requirements; otherwise, perform step 16, adjust the value of the parameter item, and perform the next trial calculation. until a suitable value is obtained.

Among them, the sixth formula is: KN=αR _g A, where K represents the safety factor, N represents the axial force, α represents the eccentric influence coefficient of the axial force, R _g represents the tensile and compressive ultimate strength of the truss material, and A represents the equivalent The cross-sectional area of the space shell.

Optionally, the eccentric influence coefficient of the axial force is related to the eccentricity of the axial force and the thickness of the equivalent space shell. For example, Among them, e ₀ represents the eccentricity of the axial force, and h represents the thickness of the equivalent space shell.

In addition to verifying the tension and compression safety of the support, the shear safety of the support can also be verified. Specifically, step 15 further includes: calculating a corresponding verification result by using the seventh formula; and determining that the shear safety of the tunnel support structure meets the requirements when the verification result is that the safety factor is greater than or equal to the first value. Assuming that the first value is 2.4, then when K is greater than or equal to 2.4, the value of the parameter item of the tunnel support structure meets the shear safety requirements; otherwise, perform step 16 to adjust the value of the parameter item and proceed to the next test Count until you get the right value. Among them, the seventh formula is:

K represents the safety factor, Q represents the shear force, R _g represents the tensile and compressive ultimate strength of the truss material, A _k represents the cross-sectional area of the connector, l _e represents the length of the beam element selected in the finite element algorithm, θ ₁ represents the connector The angle between the center direction of the rod and the horizontal direction, c represents the circumferential spacing of the connecting parts. Optionally, the seventh constant can be 0.8, correspondingly,

In this way, through the calculation of the shear strength, the diameter d of the connector and the circumferential spacing c can meet the requirements of the shear strength of the structure.

The safety verification method at the stage of erecting the steel frame has been introduced above, and the safety verification method after the shotcrete stage will be further introduced below.

Specifically, step 15 includes: after the shotcrete stage, when it is determined as a large eccentric compression member according to the height of the concrete compression zone, the eighth formula is used to calculate the corresponding verification result; when the verification result is that the safety factor is greater than or equal to the first When the value is 1, it is determined that the tension and compression safety of the tunnel support structure meets the requirements.

Among them, the eighth formula is:

KNe＝R _w bX(h ₀ -x/2)+R _g A' _g (h ₀ -a')

in,

K represents the safety factor, N represents the axial force, e and e' represent the distance from the center of gravity of the bar in the tension and compression zone to the point where the axial force acts, R _w represents the ultimate strength of the concrete bending compressive force, b represents the longitudinal width of the calculation unit, x represents the height of the concrete compression zone (the unit can be m), R _g represents the tensile and compressive ultimate strength of the material of the truss, A _g and A' _g represent the cross-sectional area of the rod body in the tension and compression zone (the unit can be m ² ), a, a' represent the shortest distance from the center of gravity of the rod body in the tension and compression zone to the edge of the section of the equivalent space shell (the unit can be m), and h ₀ represents the effective height of the section of the equivalent space shell , h ₀ =ha.

Specifically, in the stress stage after the sprayed concrete stage, the moment of the acting point of the axial force is R _g (A _g eA' _g e')=R _w bx(eh ₀ -x/2), from which Deduced: Among them, R _w represents the concrete bending compressive ultimate strength, x represents the height of the concrete compression zone, R _g and R' _g represent the tensile and compressive strength of the truss material, and A _g and A' _g represent the tensile and The cross-sectional area of the bar in the compression zone, e, e' represent the distance from the center of gravity of the bar in the tension and compression area to the point where the axial force acts, a, a' represent the center of gravity of A _g , A' _g to the equivalent space shell The closest distance to the edge of the section of the body, h ₀ represents the effective height of the section of the equivalent space shell.

Correspondingly, assuming that the threshold value is 0.55h ₀ , then when x is less than or equal to 0.55h ₀ , it is a large eccentric compression member, which is calculated according to the eighth formula, that is, KNe=R _w bx(h ₀ -x/2)+ R _g A' _g (h ₀ -a'), the calculation needs to satisfy x≥2a', if not, that is, when x<2a', calculate according to KNe'=R _g A _g (h ₀ -a').

Specifically, step 15 includes: after the shotcrete stage, when it is judged as a small eccentric compression member according to the height of the concrete compression zone, the ninth formula is used to calculate the corresponding verification result; when the verification result is that the safety factor is greater than or equal to the first When the value is 1, it is determined that the tension and compression safety of the tunnel support structure meets the requirements. Among them, the ninth formula is: Among them, K represents the safety factor, N represents the axial force, e represents the distance from the center of gravity of the bar body to the point where the axial force acts, R _a represents the ultimate compressive strength of the concrete, b represents the longitudinal width of the calculation unit, and R _g represents the tension and compression of the truss material Ultimate strength, A' _g represents the cross-sectional area of the rod body, a' represents the shortest distance from the center of gravity of the rod body to the section edge of the equivalent space shell, and _h0 represents the effective height of the cross-section of the equivalent space shell.

Correspondingly, assuming that the threshold value is 0.55h ₀ , then when x is greater than 0.55h ₀ , it is a small eccentric compression member, and the section strength is calculated according to the ninth formula, and the eighth constant can be 0.5, namely

The calculation method of the main reinforcement at this construction stage has been introduced above, and the safety factor after reinforcement will be further introduced below:

In this embodiment, it is assumed that the first value is 2.4, that is, when K is greater than or equal to 2.4, it means that the design values of the parameter items of the tunnel support structure meet the tension and compression safety requirements.

The above is mainly for the design and verification of the value of the parameter item of the rod body in the tunnel support structure. The following will further design and verify the value of the parameter item of the connector with examples.

Specifically, according to the calculated internal force and the material strength of the truss, the safety of the tunnel support structure is verified, and the corresponding verification result is obtained. The step also includes: using the tenth formula to calculate the corresponding verification result; the verification result is the safety factor When greater than or equal to the first value, it is determined that the shear safety of the tunnel support structure meets the requirements. Among them, the tenth formula is:

K represents the safety factor, Q represents the shear force, R _a represents the ultimate compressive strength of concrete, b represents the longitudinal width of the calculation unit, h ₀ represents the effective height of the section of the equivalent space shell, R _g represents the tension and compression limit of the material of the truss Strength, A _k represents the cross-sectional area of the connector, l _e represents the length of the beam element selected in the finite element algorithm, θ ₁ represents the angle between the center of the connecting member and the horizontal direction, and c represents the circumferential spacing of the connecting member. Suppose the ninth constant is 0.07, and the tenth constant is 0.8. Correspondingly, the tenth formula is:

Further, in the embodiment of the present invention, step 16 includes: when the verification result is that the safety factor is less than the safety requirement threshold, increasing the value of the parameter item; when the verification result is that the safety factor exceeds the safety requirement threshold and reaches a specific value, Reduce the value of the parameter item; when the verification result shows that the safety factor exceeds the safety requirement threshold and does not reach a specific value, keep the set value of the parameter item unchanged. Taking the safety factor K as an example, assuming that the first value is 2.4, if K<2.4, it means that the safety margin of the current design value of the parameter item of the tunnel support structure is insufficient, and it is necessary to increase the design value and recalculate; if K> >2.4, it means that the bearing capacity of the tunnel support structure is relatively rich, and it is necessary to reduce the design value of the parameter item and recalculate; when K is slightly greater than 2.4, it indicates that the bearing capacity of the tunnel support structure can meet the requirements, and is relatively economy.

It is worth pointing out that the initial support is used as a temporary structure during the construction period to bear the proportional coefficient of the surrounding rock load. After the secondary lining is installed, its force will be improved. Therefore, there is no need to check and calculate the crack width during the construction period. , but it can be used as a reference indicator when designing. For reinforced concrete members under tension, bending and eccentric compression, for the eccentric compression members with e ₀ ≤ 0.55h ₀ , the crack width may not be checked. In other cases, calculate the crack width according to the following formula:

Among them, ω _max represents the maximum crack width (the unit can be mm); α represents the characteristic coefficient of component stress of the tunnel support structure, and the tunnel is an eccentric compression member, and α can be 1.9; Indicates the non-uniform coefficient of strain in longitudinal tension steel bars between cracks, when /> when, /> Take 0.2, when /> when, /> Take 0.2, when when, /> Take 1.0, for members directly bearing repeated loads, /> ρ te is taken as 1.0; ρ _te represents the reinforcement ratio of longitudinal tensile reinforcement calculated according to the effective tensile concrete area, ρ _te =A _s /A _ce , when ρ _te <0.01, ρ _{te is} taken as 0.01; A _s represents the longitudinal Reinforcement cross-sectional area; A _ce represents the effective tensile concrete cross-sectional area, A _ce = 0.5bh; C _s represents the distance from the outer edge of the outermost longitudinal tension kilogram to the bottom edge of the tension zone (unit can be mm), when C _s When <20, C _s is 20, when C _s > 65, C _s is 65; d indicates the diameter of the steel bar (the unit can be mm), when using steel bars with different diameters, d=4A _s /(γμ), μ Indicates the sum of the perimeter of the cross-section of the longitudinal tension reinforcement; γ indicates the surface characteristic coefficient of the longitudinal tension reinforcement, 1 for the ribbed reinforcement and 0.7 for the smooth reinforcement; E _s represents the elastic modulus of the reinforcement (the unit can be MPa); σ _s Indicates the stress of the longitudinal tensile reinforcement (unit can be MPa), σ _s =N _s (ez)/(A _s z), N _s indicates the axial force value calculated according to the load combination, z indicates the resultant force point to The distance of the resultant force point in the compression zone, z=[0.87-0.12(h ₀ /e) ² ]h ₀ , and z<0.87h ₀ .

In addition, according to the calculated internal force and the material strength of the truss, verify the safety of the tunnel support structure, and obtain the corresponding verification results, but are not limited to the following methods:

Assume a safety factor slightly larger than the first value, and put the value of the safety factor into the following inequality. If the inequality holds, the design value of the parameter item of the current support structure is considered to meet the safety requirements.

Specifically, the value of the safety factor K is brought into KN≤αR _g A, and if the inequality holds true, it is determined that the tensile and compressive safety of the tunnel support structure meets the requirements.

Will If the inequality is established, it is determined that the shear safety of the tunnel support structure meets the requirements.

After the sprayed concrete stage, when the height of the concrete compression zone is judged as a large eccentric compression member, the value of the safety factor K is brought into KNe≤R _w bx(h ₀ -x/2)+R _g A' _g ( h ₀ -a'), if the inequality is established, it is determined that the tension and compression safety of the tunnel support structure meets the requirements.

After the shotcrete stage, when it is judged as a small eccentric compression member according to the height of the concrete compression zone, the If the inequality is established, it is determined that the tension and compression safety of the tunnel support structure meets the requirements.

Will If the inequality is established, it is determined that the shear safety of the tunnel support structure meets the requirements.

It is worth pointing out that when the inequality does not hold, it means that the safety margin of the current design value of the parameter item of the tunnel support structure is insufficient, and it is necessary to increase the design value and recalculate; When , it means that the bearing capacity of the tunnel support structure is relatively rich, and it is necessary to reduce the design value of the parameter item and recalculate; when the inequality is established, and the result on the left side of the inequality is slightly smaller than the result on the right side, it means that the bearing capacity of the tunnel support structure can meet requirements, and more economical.

To sum up, the method for determining the parameters of the tunnel support structure provided in the embodiment of the present invention can realize the parameter design of the support structure that can provide a large load-bearing capacity before spraying concrete, and ensure that the designed support structure can meet the construction requirements. Safe, because the supporting structure can provide a large bearing capacity before spraying concrete, it can realize the next process without spraying concrete within a certain working range, which improves the construction efficiency.

The above embodiments respectively introduce in detail the methods for determining the parameters of the tunnel support structure in different scenarios. The following embodiments will further introduce the corresponding device for determining the parameters of the tunnel support structure with reference to the accompanying drawings.

Another aspect of the embodiment of the present invention also provides a parameter determination device for a tunnel support structure, as shown in Figure 4, the device 400 includes the following functional modules:

The first acquisition module 410 is used to acquire the setting values of the parameter items of the tunnel support structure and the tunnel model; wherein, the tunnel support structure includes at least two mutually assembled trusses, and the trusses include: the connection between the stressed rod body and the connecting rod body pieces;

The first calculation module 420 is used to calculate the bearing load of the tunnel support structure according to the set value of the parameter item and the tunnel model;

The second calculation module 430 is used to calculate the elastic modulus of the equivalent space shell of the tunnel support structure according to the set value of the parameter item;

The third calculation module 440 is used for simulating the tunnel support structure using a finite element model, using the elastic modulus as a material parameter of the simulated tunnel support structure and applying a bearing load, and calculating the internal force of the simulated tunnel support structure;

The verification module 450 is used to verify the safety of the tunnel support structure according to the internal force and the material strength of the truss, and obtain corresponding verification results;

The adjustment module 460 is configured to adjust the value of the parameter item according to the verification result.

Optionally, the first calculation module 420 includes:

The first calculation submodule is used to calculate the self-weight load of the tunnel support structure according to the set value of the parameter item;

The second calculation submodule is used to calculate the external load of the tunnel support structure according to the tunnel model;

The first determination sub-module is used to determine the self-weight load and the external load as bearing loads of the tunnel support structure.

Optionally, the first computing submodule includes:

The first calculation unit is used to calculate the self-weight load f of the tunnel support structure by using the first formula; wherein, the first formula is:

f=γ ₁ V ₁ ;

Among them, _γ1 represents the material weight of the tunnel support structure, and _V1 represents the volume of the calculation unit.

Optionally, the second calculation submodule includes at least one of the following:

The second calculation unit is used to calculate the formation resistance borne by the tunnel support structure according to the tunnel model and geological parameters;

The third calculation unit is used to calculate the surrounding rock pressure borne by the tunnel support structure according to the tunnel model and geological parameters.

Optionally, the second computing unit includes:

The first calculation subunit is used to determine the formation resistance coefficient of the tunnel model according to the geological parameters of the surrounding rock of the tunnel;

The equivalent sub-unit is used to use the Winkel assumption algorithm to equate the tunnel surrounding rock and the tunnel model into a spring group;

The second calculation subunit is used to assign the formation resistance coefficient to the spring group and calculate the formation resistance borne by the tunnel support structure.

Optionally, the second computing submodule also includes:

The adjustment unit is used to adjust the surrounding rock pressure according to the load coefficient, wherein the load coefficient is the proportion of the surrounding rock load borne by the tunnel support structure in actual engineering.

Optionally, the third calculation unit includes:

The third calculation sub-unit is used to separately calculate the vertical uniform pressure and horizontal uniform pressure of the surrounding rock borne by the tunnel support structure according to the tunnel model and geological parameters.

Optionally, the third calculation subunit is also used for:

In the case that the tunnel model is a deep tunnel, the second formula is used to calculate the vertical uniform pressure q of the surrounding rock borne by the tunnel support structure; where the second formula is:

q＝γ ₂ h _q

Wherein, h _q =first constant×2 ^S-1 w, w=second constant+i(B-third constant);

Among them, γ ₂ represents the weight of the surrounding rock, h _q represents the calculated height of the surrounding rock collapse arch, S represents the level of the surrounding rock, w represents the width influence coefficient, B represents the width of the tunnel excavation, and i represents the surrounding rock per unit of excavation width Pressure increase and decrease rate.

Optionally, the third calculation subunit is also used for:

When the tunnel model is a deep-buried tunnel, the product of the vertical uniform pressure of the surrounding rock borne by the tunnel support structure and a specific coefficient is determined as the horizontal uniform pressure of the surrounding rock borne by the tunnel support structure, where the specific coefficient The value of is related to the surrounding rock level.

Optionally, the third calculation subunit is also used for:

When the tunnel model is a shallow tunnel, the third formula is used to calculate the vertical uniform pressure q of the surrounding rock borne by the tunnel support structure; where the third formula is:

in,

γ ₂ represents the weight of the surrounding rock, h ₂ represents the height of the tunnel top from the ground, λ represents the lateral pressure coefficient, θ represents the friction angle on both sides of the tunnel top, B represents the tunnel excavation width, β represents the rupture angle at the maximum thrust, Indicates the calculated friction angle of the surrounding rock.

Optionally, the third calculation subunit is also used for:

In the case that the tunnel model is a shallow tunnel, the fourth formula is used to calculate the horizontal uniform pressure e _i of the surrounding rock borne by the tunnel support structure; where the fourth formula is:

e _i =γ ₂ h _i λ

Among them, _γ2 represents the weight of the surrounding rock, h _i represents the distance from any point in the tunnel to the ground, and λ represents the lateral pressure coefficient.

Optionally, the second calculation module 430 includes:

The third calculation sub-module is used to calculate the elastic modulus E of the equivalent space shell of the tunnel support structure by using the fifth formula; wherein, the fifth formula is:

Among them, A _g and A' _g represent the cross-sectional area of the rod body in the tension and compression zone, E _g represents the elastic modulus of the rod body, L represents the effective longitudinal length of a truss in the tunnel support structure, and h represents the equivalent space shell thickness of.

Among them, in the case that the rod body is a steel bar, Among them, n represents the number of rods contained in the longitudinal section of a truss, and D represents the diameter of the steel bar.

Among them, in the case that the rod body is a steel bar, Among them, n represents the number of rods contained in the longitudinal section of a truss, D represents the diameter of the steel pipe, and t represents the wall thickness of the steel pipe.

Optionally, the internal force parameters include at least one of bending moment, axial force and shear force.

Optionally, verification module 450 includes:

The fourth calculation sub-module is used to calculate the corresponding verification results using the sixth formula at the stage of erecting the truss; the sixth formula is: KN=αR _g A, where K represents the safety factor, N represents the axial force, and α Indicates the eccentric influence coefficient of the axial force, R _g indicates the tensile and compressive ultimate strength of the material of the truss, and A indicates the cross-sectional area of the equivalent space shell;

The second determination sub-module is used to determine that the tension and compression safety of the tunnel support structure meets the requirements when the verification result is that the safety factor is greater than or equal to the first value.

Optionally, the eccentric influence coefficient of the axial force is related to the eccentricity of the axial force and the thickness of the equivalent space shell.

Optionally, the verification module 450 also includes: a fifth calculation sub-module, configured to calculate a corresponding verification result using a seventh formula; wherein, the seventh formula is:

K represents the safety factor, Q represents the shear force, R _g represents the tensile and compressive ultimate strength of the truss material, A _k represents the cross-sectional area of the connector, l _e represents the length of the beam element selected in the finite element algorithm, θ ₁ represents the connector The angle between the center direction of the rod and the horizontal direction, c represents the circumferential distance of the connector;

The third determination sub-module is used to determine that the shear safety of the tunnel support structure meets the requirements when the verification result is that the safety factor is greater than or equal to the first value.

Optionally, verification module 450 also includes:

The sixth calculation sub-module is used to calculate the corresponding verification result by using the eighth formula when it is judged as a large eccentric compression member according to the height of the concrete compression zone after the shotcrete stage; the eighth formula is:

KNe＝R _w bX(h ₀ -x/2)+R _g A' _g (h ₀ -a')

in,

K represents the safety factor, N represents the axial force, e and e' represent the distance from the center of gravity of the bar in the tension and compression zone to the point where the axial force acts, R _w represents the ultimate strength of the concrete bending compressive force, b represents the longitudinal width of the calculation unit, x represents the height of the concrete compression zone, R _g represents the tensile and compressive ultimate strength of the truss material, A _g and A' _g represent the cross-sectional area of the rod in the tension and compression region, a and a' represent the tension and compression The shortest distance from the center of gravity of the rod body in the area to the section edge of the equivalent space shell, _h0 represents the effective height of the section of the equivalent space shell;

The fourth determination sub-module is used to determine that the tension and compression safety of the tunnel support structure meets the requirements when the verification result is that the safety factor is greater than or equal to the first value.

Optionally, the verification module 450 also includes:

The seventh calculation sub-module is used to calculate the corresponding verification results by using the ninth formula when it is determined as a small eccentric compression member according to the height of the concrete compression zone after the shotcrete stage; the ninth formula is:

Among them, K represents the safety factor, N represents the axial force, e represents the distance from the center of gravity of the bar body to the point where the axial force acts, R _a represents the ultimate compressive strength of the concrete, b represents the longitudinal width of the calculation unit, and R _g represents the tension and compression of the truss material Ultimate strength, A' _g represents the cross-sectional area of the rod body, a' represents the shortest distance from the center of gravity of the rod body to the section edge of the equivalent space shell, and _h0 represents the effective height of the cross-section of the equivalent space shell;

The fifth determination sub-module is used to determine that the tension and compression safety of the tunnel support structure meets the requirements when the verification result is that the safety factor is greater than or equal to the first value.

Optionally, the verification module 450 also includes: an eighth calculation submodule, configured to calculate a corresponding verification result using a tenth formula; wherein, the tenth formula is:

K represents the safety factor, Q represents the shear force, R _a represents the ultimate compressive strength of concrete, b represents the longitudinal width of the calculation unit, h ₀ represents the effective height of the section of the equivalent space shell, R _g represents the tension and compression limit of the material of the truss Strength, A _k represents the cross-sectional area of the connector, l _e represents the length of the beam element selected in the finite element algorithm, θ ₁ represents the angle between the center of the connecting member and the horizontal direction, and c represents the circumferential distance of the connecting member;

The sixth determination sub-module is used to determine that the shear safety of the tunnel support structure meets the requirements when the verification result is that the safety factor is greater than or equal to the first value.

Optionally, the adjustment module 460 includes:

The first adjustment submodule is used to increase the value of the parameter item when the verification result is that the safety factor is less than the safety requirement threshold;

The second adjustment submodule is used to reduce the value of the parameter item when the verification result is that the safety factor exceeds the safety requirement threshold and reaches a specific value;

The third adjustment sub-module is used to keep the set value of the parameter item unchanged when the verification result is that the safety factor exceeds the safety requirement threshold but does not reach a specific value.

It is worth noting that the above device embodiments are product embodiments corresponding to the above methods, and all embodiments applicable to the above methods are also applicable to the device embodiments, so details are not repeated here. The device of the embodiment of the present invention can realize the parameter design of the support structure that can provide a larger load-bearing capacity before the sprayed concrete, and ensure that the designed support structure can meet the construction safety, because the support structure can be used before the sprayed concrete It provides a large bearing capacity, which can realize the next process without spraying concrete within a certain operating range, and improves the construction efficiency.

Those skilled in the art should understand that the embodiments of the present invention may be provided as methods, systems, or computer program products. Accordingly, the present invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (28)

1. A method for determining parameters of a tunnel supporting structure, comprising:

acquiring a set value of a parameter item of a tunnel supporting structure and a tunnel model; wherein, tunnel supporting construction includes two piece at least trusses of assembling each other, the truss includes: the device comprises a stressed rod body and a connecting piece connected with the rod body;

calculating the bearing load of the tunnel supporting structure according to the set value of the parameter item and the tunnel model;

according to the set value of the parameter item, calculating the elastic modulus of an equivalent space shell of the tunnel supporting structure;

simulating a tunnel supporting structure by adopting a finite element model, taking the elastic modulus as a material parameter of the simulated tunnel supporting structure, applying the bearing load, and calculating the internal force of the simulated tunnel supporting structure;

verifying the safety of the tunnel supporting structure according to the internal force and the material strength of the truss, which are obtained through calculation, so as to obtain a corresponding verification result;

According to the verification result, adjusting the value of the parameter item;

according to the set value of the parameter item and the tunnel model, the step of calculating the bearing load of the tunnel supporting structure comprises the following steps:

according to the set value of the parameter itemCalculating the dead weight load f of the tunnel supporting structure by adopting a first formula; the first formula is: f=γ ₁ V ₁； wherein ,γ₁ Representing the material weight of the tunnel supporting structure, V ₁ Representing the volume of the computing unit;

according to the tunnel model, calculating the external load of the tunnel supporting structure;

determining the dead weight load and the external load as the bearing load of the tunnel supporting structure;

according to the tunnel model, calculating the external load of the tunnel supporting structure, wherein the method comprises at least one of the following steps:

according to the tunnel model and the geological parameters, calculating stratum resistance born by the tunnel supporting structure;

according to the tunnel model and the geological parameters, calculating the surrounding rock pressure born by the tunnel supporting structure; the method specifically comprises the following steps: according to the tunnel model and the geological parameters, respectively calculating the vertical uniform distribution pressure and the horizontal uniform distribution pressure of surrounding rock born by the tunnel supporting structure;

Under the condition that the tunnel model is a deep buried tunnel, calculating the surrounding rock vertical uniform distribution pressure q born by the tunnel supporting structure by adopting a second formula; wherein the second formula is:

q＝γ ₂ h _q

wherein ,h_q =first constant×2 ^S-1 w, w=second constant+i (B-third constant);

wherein ,γ₂ Indicating the surrounding rock weight, h _q Calculating the height of the surrounding rock slump arch, wherein S represents the level of the surrounding rock, w represents the width influence coefficient, B represents the tunnel excavation width, and i represents the pressure increasing and decreasing rate of the surrounding rock per unit excavation width;

under the condition that the tunnel model is a shallow tunnel, calculating the surrounding rock vertical uniform distribution pressure q born by the tunnel supporting structure by adopting a third formula; wherein the third formula is:

wherein ,

γ ₂ indicating the surrounding rock weight, h ₂ Represents the height of the tunnel roof from the ground, λ represents the side pressure coefficient, θ represents the friction angle on both sides of the tunnel roof, B represents the tunnel excavation width, β represents the burst angle at maximum thrust,representing the surrounding rock to calculate the friction angle;

under the condition that the tunnel model is a shallow tunnel, calculating the surrounding rock Shui Pingyun distribution pressure e born by the tunnel supporting structure by adopting a fourth formula _i The method comprises the steps of carrying out a first treatment on the surface of the Wherein the fourth formula is:

e _i ＝γ ₂ h _i λ

wherein ,γ₂ Indicating the surrounding rock weight, h _i Represents the distance from any point in the tunnel to the ground, and lambda represents the side pressure coefficient;

according to the set value of the parameter item, calculating the elastic modulus of the equivalent space shell of the tunnel supporting structure, wherein the step comprises the following steps:

adopting a fifth formula to calculate the elastic modulus E of the equivalent space shell of the tunnel supporting structure; wherein the fifth formula is:

wherein ,A_g 、A‘ _g Representing the cross-sectional area of the body in tension and compression zone E _g Elastic die for representing the rod bodyAnd L represents the effective longitudinal length of one truss in the tunnel supporting structure, and h represents the thickness of the equivalent space shell.

2. The method for determining parameters of a tunnel support structure according to claim 1, wherein the step of calculating the formation resistance to which the tunnel support structure is subjected based on the tunnel model and the geological parameters comprises:

determining a stratum resistance coefficient of the tunnel model according to geological parameters of tunnel surrounding rock;

adopting a Wenker assumption algorithm to make the tunnel surrounding rock and the tunnel model equivalent to a spring group;

and giving the stratum resistance coefficient to the spring group, and calculating the stratum resistance born by the tunnel supporting structure.

3. The method for determining parameters of a tunnel supporting structure according to claim 1, further comprising, after the step of calculating the surrounding rock pressure to which the tunnel supporting structure is subjected according to the tunnel model and the geological parameters:

and adjusting the surrounding rock pressure according to a load coefficient, wherein the load coefficient is the proportion of the bearing surrounding rock load of the tunnel supporting structure in actual engineering.

4. The method for determining parameters of a tunnel supporting structure according to claim 1, wherein the step of calculating the surrounding rock Shui Pingyun distribution pressure born by the tunnel supporting structure according to the tunnel model and the geological parameters comprises the following steps:

and under the condition that the tunnel model is a deeply buried tunnel, determining the product of the surrounding rock vertical uniform distribution pressure born by the tunnel supporting structure and a specific coefficient as the surrounding rock Shui Pingyun distribution pressure born by the tunnel supporting structure, wherein the value of the specific coefficient is related to the surrounding rock level.

5. The method for determining parameters of a tunnel supporting structure according to claim 1,it is characterized in that in the case that the rod body is a reinforcing steel bar,

wherein n represents the number of rods included in the longitudinal section of one truss, and D represents the diameter of the steel bar.

6. The method for determining parameters of a tunnel supporting structure according to claim 1, wherein, in the case where the rod body is a steel pipe,

where n represents the number of rods included in the longitudinal section of one truss, D represents the diameter of the steel pipe, and t represents the wall thickness of the steel pipe.

7. The method of claim 1, wherein the internal force parameter comprises at least one of bending moment, axial force, and shear force.

8. The method for determining parameters of a tunnel supporting structure according to claim 7, wherein the step of verifying the safety of the tunnel supporting structure according to the calculated internal force and the material strength of the truss to obtain a corresponding verification result comprises:

in the stage of erecting the truss, calculating a corresponding verification result by adopting a sixth formula; the sixth formula is: kn=αr _g A, wherein K represents a safety coefficient, N represents an axial force, alpha represents an eccentric influence coefficient of the axial force, R _g Representing the tensile and compressive ultimate strength of the material of the truss, a representing the cross-sectional area of the equivalent space shell;

and when the verification result is that the safety coefficient is larger than or equal to a first value, determining that the tension and compression safety of the tunnel supporting structure meets the requirement.

9. The method of claim 8, wherein the eccentricity influence coefficient of the axial force is related to the axial force eccentricity and the thickness of the equivalent space housing.

10. The method for determining parameters of a tunnel supporting structure according to claim 7, wherein verifying the safety of the tunnel supporting structure according to the calculated internal force and the truss material strength, and obtaining a corresponding verification result, further comprises:

calculating a corresponding verification result by adopting a seventh formula; wherein the seventh formula is:

k represents a safety coefficient, Q represents shearing force, R _g Represents the tensile and compressive ultimate strength of the material of the truss, A _k Representing the cross-sectional area of the connector, l _e Representing the length of selected beam elements in the finite element algorithm, 0 ₁ Representing an included angle between the central direction and the horizontal direction of the connecting piece rod piece, and c represents the circumferential spacing of the connecting piece;

and when the verification result is that the safety coefficient is larger than or equal to a first value, determining that the shearing safety of the tunnel supporting structure meets the requirement.

11. The method for determining parameters of a tunnel supporting structure according to claim 7, wherein the step of verifying the safety of the tunnel supporting structure according to the calculated internal force and the material strength of the truss to obtain a corresponding verification result comprises:

After the concrete spraying stage, when the large eccentric pressed component is determined according to the height of the concrete pressed zone, calculating a corresponding verification result by adopting an eighth formula; the eighth formula is:

KNe＝R _w bx(h ₀ -x/2)+R _g A‘ _g (h ₀ -a’)

wherein ,

k represents a safety factor, N represents axial force, e and e' represent distances from the center of gravity of the rod body to an axial force acting point in the tension and compression area, R _w Represents the flexural compressive ultimate strength of the concrete, b represents the longitudinal width of the computing unit, x represents the height of the concrete compression zone, R _g Represents the tensile and compressive ultimate strength of the material of the truss, A _g 、A‘ _g Representing the cross-sectional area of the rod in the tension and compression zone, a' representing the closest distance, h, between the center of gravity of the rod in the tension and compression zone and the cross-sectional edge of the equivalent space shell ₀ Representing the effective height of a cross section of the equivalent space housing;

and when the verification result is that the safety coefficient is larger than or equal to a first value, determining that the tension and compression safety of the tunnel supporting structure meets the requirement.

12. The method for determining parameters of a tunnel supporting structure according to claim 7, wherein the step of verifying the safety of the tunnel supporting structure according to the calculated internal force and the material strength of the truss to obtain a corresponding verification result comprises:

After the concrete spraying stage, when the small eccentric pressed component is judged according to the height of the concrete pressed zone, a ninth formula is adopted to calculate a corresponding verification result; the ninth formula is:

wherein K represents a safety coefficient, N represents an axial force, e represents a distance from the center of gravity of the rod body to an axial force acting point, R _a Represents the compressive ultimate strength of the concrete, b represents the longitudinal width of the computing unit, R _g Representing the tensile and compressive ultimate strength, A ', of the material of the truss' _g Representing the cross-sectional area of the rod, a' representing the rodThe nearest distance of the center of gravity to the cross-sectional edge of the equivalent space housing, h ₀ Representing the effective height of a cross section of the equivalent space housing;

and when the verification result is that the safety coefficient is larger than or equal to a first value, determining that the tension and compression safety of the tunnel supporting structure meets the requirement.

13. The method for determining parameters of a tunnel supporting structure according to claim 11 or 12, wherein the step of verifying the safety of the tunnel supporting structure according to the calculated internal force and the material strength of the truss to obtain a corresponding verification result further comprises:

adopting a tenth formula to calculate a corresponding verification result; wherein the tenth formula is:

K represents a safety coefficient, Q represents shearing force, R _a Represents the compressive ultimate strength of the concrete, b represents the longitudinal width of the computing unit, h ₀ Representing the effective height of the cross section of the equivalent space housing, R _g Represents the tensile and compressive ultimate strength of the material of the truss, A _k Representing the cross-sectional area of the connector, l _e Representing the length, θ, of a selected beam element in a finite element algorithm ₁ Representing an included angle between the central direction and the horizontal direction of the connecting piece rod piece, and c represents the circumferential spacing of the connecting piece;

and when the verification result is that the safety coefficient is larger than or equal to a first value, determining that the shearing safety of the tunnel supporting structure meets the requirement.

14. The method for determining parameters of a tunnel supporting structure according to claim 1, wherein the step of adjusting the values of the parameter items according to the verification result comprises:

when the verification result is that the safety coefficient is smaller than the safety requirement threshold value, increasing the value of the parameter item;

when the verification result is that the safety coefficient exceeds the safety requirement threshold value to reach a specific value, reducing the value of the parameter item;

and when the verification result is that the safety coefficient exceeds the safety requirement threshold value and the specific value is not reached, keeping the set value of the parameter item unchanged.

15. A parameter determining apparatus for a tunnel supporting structure, comprising:

the first acquisition module is used for acquiring set values of parameter items of the tunnel supporting structure and a tunnel model; the tunnel supporting structure comprises at least two annular trusses which are mutually assembled, and the trusses comprise: the device comprises a stressed rod body and a connecting piece connected with the rod body;

the first calculation module is used for calculating the bearing load of the tunnel supporting structure according to the set value of the parameter item and the tunnel model;

the second calculation module is used for calculating the elastic modulus of the equivalent space shell of the tunnel supporting structure according to the set value of the parameter item;

the third calculation module is used for simulating a tunnel supporting structure by adopting a finite element model, taking the elastic modulus as a material parameter of the simulated tunnel supporting structure, applying the bearing load and calculating the internal force of the simulated tunnel supporting structure;

the verification module is used for verifying the safety of the tunnel supporting structure according to the internal force and the material strength of the truss to obtain a corresponding verification result;

the adjustment module is used for adjusting the value of the parameter item according to the verification result;

the first computing module includes:

The first calculation sub-module is used for calculating the dead weight load of the tunnel supporting structure according to the set value of the parameter item;

the second calculation sub-module is used for calculating the external load of the tunnel supporting structure according to the tunnel model;

the first determining submodule is used for determining the dead load and the external load as the bearing load of the tunnel supporting structure;

the first computing submodule includes:

the first calculation unit is used for calculating the dead weight load f of the tunnel supporting structure by adopting a first formula; wherein, the first formula is:

f＝γ ₁ V ₁ ；

wherein ,γ₁ Representing the material weight of the tunnel supporting structure, V ₁ Representing the volume of the computing unit; the second computing submodule includes at least one of:

the second calculation unit is used for calculating stratum resistance born by the tunnel supporting structure according to the tunnel model and the geological parameters;

the third calculation unit is used for calculating the surrounding rock pressure born by the tunnel supporting structure according to the type and the geological parameters of the tunnel model; the third computing unit includes:

the third calculation subunit is used for respectively calculating the vertical distribution pressure and the horizontal distribution pressure of the surrounding rock born by the tunnel supporting structure according to the tunnel model and the geological parameters;

The third computing subunit is further configured to: under the condition that the tunnel model is a deep buried tunnel, calculating the surrounding rock vertical uniform distribution pressure q born by the tunnel supporting structure by adopting a second formula; wherein the second formula is:

q＝γ ₂ h _q

wherein ,h_q =first constant×2 ^S-1 w, w=second constant+i (B-third constant);

wherein ,γ₂ Indicating the surrounding rock weight, h _q Calculating the height of the surrounding rock slump arch, wherein S represents the level of the surrounding rock, w represents the width influence coefficient, B represents the tunnel excavation width, and i represents the pressure increasing and decreasing rate of the surrounding rock per unit excavation width;

the third computing subunit is further configured to: under the condition that the tunnel model is a shallow tunnel, calculating the surrounding rock vertical uniform distribution pressure q born by the tunnel supporting structure by adopting a third formula; wherein the third formula is:

wherein ,

γ ₂ indicating the surrounding rock weight, h ₂ Represents the height of the tunnel roof from the ground, λ represents the side pressure coefficient, θ represents the friction angle on both sides of the tunnel roof, B represents the tunnel excavation width, β represents the burst angle at maximum thrust,representing the surrounding rock to calculate the friction angle;

the third computing subunit is further configured to: under the condition that the tunnel model is a shallow tunnel, calculating the surrounding rock Shui Pingyun distribution pressure e born by the tunnel supporting structure by adopting a fourth formula _i The method comprises the steps of carrying out a first treatment on the surface of the Wherein the fourth formula is:

e _i ＝γ ₂ h _i λ

wherein ,γ₂ Indicating the surrounding rock weight, h _i Represents the distance from any point in the tunnel to the ground, and lambda represents the side pressure coefficient;

the second computing module includes: the third calculation sub-module is used for calculating the elastic modulus E of the equivalent space shell of the tunnel supporting structure by adopting a fifth formula; wherein the fifth formula is:

wherein ,A_g 、A‘ _g Representing the cross-sectional area of the body in tension and compression zone E _g And the elastic modulus of the rod body is represented, L represents the effective longitudinal length of a truss in the tunnel supporting structure, and h represents the thickness of the equivalent space shell.

16. The parameter determination apparatus of a tunnel supporting structure according to claim 15, wherein the second calculation unit comprises:

the first calculation subunit is used for determining the stratum resistance coefficient of the tunnel model according to the geological parameters of the surrounding rock of the tunnel;

the equivalent subunit is used for adopting a Winker assumption algorithm to equivalent the tunnel surrounding rock and the tunnel model into a spring group;

and the second calculating subunit is used for giving the stratum resistance coefficient to the spring group and calculating stratum resistance born by the tunnel supporting structure.

17. The parameter determination apparatus of a tunnel support structure according to claim 15, wherein the second calculation sub-module further comprises:

the adjusting unit is used for adjusting the surrounding rock pressure according to a load coefficient, wherein the load coefficient is the proportion of the load of the surrounding rock born by the tunnel supporting structure in actual engineering.

18. The parameter determination apparatus of a tunnel supporting structure according to claim 15, wherein the third calculation subunit is further configured to:

and under the condition that the tunnel model is a deeply buried tunnel, determining the product of the surrounding rock vertical uniform distribution pressure born by the tunnel supporting structure and a specific coefficient as the surrounding rock Shui Pingyun distribution pressure born by the tunnel supporting structure, wherein the value of the specific coefficient is related to the surrounding rock level.

19. The parameter determining apparatus of a tunnel supporting structure according to claim 15,it is characterized in that in the case that the rod body is a reinforcing steel bar,

wherein n represents the number of rods included in the longitudinal section of one truss, and D represents the diameter of the steel bar.

20. The apparatus for determining parameters of a tunnel supporting structure according to claim 15, wherein, in case that the rod body is a steel pipe,

Where n represents the number of rods included in the longitudinal section of one truss, D represents the diameter of the steel pipe, and t represents the wall thickness of the steel pipe.

21. The parameter determination apparatus of a tunnel support structure according to claim 15, wherein the internal force parameter comprises at least one of a bending moment, an axial force, and a shearing force.

22. The parameter determination apparatus of a tunnel support structure according to claim 21, wherein the verification module comprises:

a fourth calculation sub-module, configured to calculate a corresponding verification result by using a sixth formula in a stage of erecting the truss; the sixth formula is: kn=αr _g A, wherein K represents a safety coefficient, N represents an axial force, alpha represents an eccentric influence coefficient of the axial force, R _g Representing the tensile and compressive ultimate strength of the material of the truss, a representing the cross-sectional area of the equivalent space shell;

and the second determining submodule is used for determining that the pulling and pressing safety of the tunnel supporting structure meets the requirement when the safety coefficient is larger than or equal to the first value as the verification result.

23. The device for determining parameters of a tunnel supporting structure according to claim 22, wherein the eccentricity influence coefficient of the axial force is related to the axial force eccentricity and the thickness of the equivalent space housing.

24. The parameter determination apparatus of a tunnel support structure according to claim 21, wherein the verification module further comprises:

a fifth calculation sub-module, configured to calculate a corresponding verification result by using a seventh formula; wherein the seventh formula is:

k represents a safety coefficient, Q represents shearing force, R _g Represents the tensile and compressive ultimate strength of the material of the truss, A _k Representing the cross-sectional area of the connector, l _e Representing the length, θ, of a selected beam element in a finite element algorithm ₁ Representing an included angle between the central direction and the horizontal direction of the connecting piece rod piece, and c represents the circumferential spacing of the connecting piece;

and the third determining submodule is used for determining that the shearing safety of the tunnel supporting structure meets the requirement when the safety coefficient is larger than or equal to the first value as the verification result.

25. The parameter determination apparatus of a tunnel support structure according to claim 21, wherein the verification module further comprises:

a sixth calculation sub-module, configured to calculate a corresponding verification result using an eighth formula when the concrete compression area height is determined to be a large eccentric compression member after the concrete injection stage; the eighth formula is:

KNe＝R _w bx(h ₀ -x/2)+R _g A‘ _g (h ₀ -a’)

wherein ,

k represents a safety factor, N represents an axis Forces e, e' represent the distance from the centre of gravity of the rod in the tension and compression zone to the point of application of axial force, R _w Represents the flexural compressive ultimate strength of the concrete, b represents the longitudinal width of the computing unit, x represents the height of the concrete compression zone, R _g Represents the tensile and compressive ultimate strength of the material of the truss, A _g 、A‘ _g Representing the cross-sectional area of the rod in the tension and compression zone, a' representing the closest distance, h, between the center of gravity of the rod in the tension and compression zone and the cross-sectional edge of the equivalent space shell ₀ Representing the effective height of a cross section of the equivalent space housing;

and the fourth determining submodule is used for determining that the pulling and pressing safety of the tunnel supporting structure meets the requirement when the verification result is that the safety coefficient is larger than or equal to the first value.

26. The parameter determination apparatus of a tunnel support structure according to claim 21, wherein the verification module further comprises:

a seventh calculation sub-module for calculating a corresponding verification result by using a ninth formula when the small eccentric compression member is determined according to the height of the concrete compression zone after the concrete spraying stage; the ninth formula is:

wherein K represents a safety coefficient, N represents an axial force, e represents a distance from the center of gravity of the rod body to an axial force acting point, R _a Represents the compressive ultimate strength of the concrete, b represents the longitudinal width of the computing unit, R _g Representing the tensile and compressive ultimate strength, A ', of the material of the truss' _g Representing the cross-sectional area of the rod, a' representing the closest distance from the center of gravity of the rod to the cross-sectional edge of the equivalent space housing, h ₀ Representing the effective height of a cross section of the equivalent space housing;

and the fifth determining submodule is used for determining that the tension and compression safety of the tunnel supporting structure meets the requirement when the safety coefficient is larger than or equal to the first value as the verification result.

27. The parameter determination apparatus of a tunnel support structure according to claim 25 or 26, wherein the verification module further comprises:

an eighth calculation sub-module, configured to calculate a corresponding verification result by using a tenth formula; wherein the tenth formula is:

k represents a safety coefficient, Q represents shearing force, R _a Represents the compressive ultimate strength of the concrete, b represents the longitudinal width of the computing unit, h ₀ Representing the effective height of the cross section of the equivalent space housing, R _g Represents the tensile and compressive ultimate strength of the material of the truss, A _k Representing the cross-sectional area of the connector, l _e Representing the length, θ, of a selected beam element in a finite element algorithm ₁ Representing an included angle between the central direction and the horizontal direction of the connecting piece rod piece, and c represents the circumferential spacing of the connecting piece;

and the sixth determining submodule is used for determining that the shearing safety of the tunnel supporting structure meets the requirement when the safety coefficient is larger than or equal to the first value as the verification result.

28. The apparatus for determining parameters of a tunnel supporting structure according to claim 15, wherein the adjusting module comprises:

the first adjusting sub-module is used for increasing the value of the parameter item when the verification result is that the safety coefficient is smaller than the safety requirement threshold value;

the second adjusting sub-module is used for reducing the value of the parameter item when the verification result is that the safety coefficient exceeds the safety requirement threshold value to reach a specific value;

and the third adjustment sub-module is used for keeping the set value of the parameter item unchanged when the verification result is that the safety coefficient exceeds the safety requirement threshold and the specific value is not reached.