CN112982053B

CN112982053B - Transition structure of frozen soil variable stiffness road bridge and its construction technology

Info

Publication number: CN112982053B
Application number: CN202110322046.5A
Authority: CN
Inventors: 李双洋; 游甜甜; 杨佳乐; 赵永春; 姜琪
Original assignee: Northwest Institute of Eco Environment and Resources of CAS
Current assignee: Northwest Institute of Eco Environment and Resources of CAS
Priority date: 2021-03-25
Filing date: 2021-03-25
Publication date: 2025-09-02
Anticipated expiration: 2041-03-25
Also published as: CN112982053A

Abstract

The present application provides a frozen soil variable-rigidity road bridge transition structure and its construction process. The frozen soil variable-rigidity road bridge transition structure includes a bridge abutment and a roadbed. The roadbed includes a graded crushed stone cushion layer, a reinforced concrete retaining wall, a block crushed stone filling layer, a fill layer, and a rigid slab. The reinforced concrete retaining wall is provided with multiple filling areas, and the reinforced concrete retaining wall is connected to the bridge abutment. The block crushed stone filling layer is provided within the multiple filling areas, and a slope is provided on the side of the block crushed stone filling layer facing away from the graded crushed stone cushion layer, and the height of the slope gradually decreases from the side close to the bridge abutment to the side away from the bridge abutment; the rigid slab is supported by the block crushed stone filling layer and connected to the bridge abutment. Not only does the variable-rigidity roadbed design improve the differential compaction settlement disease caused by the sudden change in stiffness of the roadbed under long-term dynamic loads, but the cooling effect of the block crushed stone filling layer is also used to prevent the permafrost foundation from melting, effectively improving the problem of vehicle jumping at the bridge head while also improving the durability of the road project.

Description

Frozen soil rigidity-variable road bridge transition structure and construction process thereof

Technical Field

The invention relates to the field of road and bridge construction, in particular to a frozen soil variable-rigidity road and bridge transition structure and a construction process thereof.

Background

Frozen soil is a soil rock below 0 ℃ and containing a portion of water frozen. The total area of frozen soil (season frozen soil and perennial frozen soil) accounts for about 75% of the area of Chinese national soil, and the construction of infrastructures such as roads, bridges and the like in perennial frozen soil areas has become an indispensable development means. However, the property of frozen soil is closely related to temperature change, the unfrozen water content of the frozen soil changes along with the change of the external environment temperature, and the characteristic determines that the mechanical and thermal properties of the frozen soil have strong dynamic property and instability, so that the roadbed of road engineering is easily unstable, and serious engineering diseases are caused. For the bridge transition section, the phenomenon that the bridge head jumps vehicles frequently occurs due to uneven settlement of the road surface and cracking of the road surface, so that the driving safety and the road surface traffic capacity are seriously influenced, meanwhile, the impact load caused by bumping of the bridge abutment jumping vehicles accelerates the degradation of the bridge abutment, the support and the like, and the service life of the road is reduced.

The research shows that the conventional frozen soil variable-rigidity road bridge transition structure has the following defects:

The variable stiffness requirement and the roadbed stability of the transition section roadbed can not be met at the same time, and the frozen ground foundation layer can not be protected.

Disclosure of Invention

The invention aims to provide a frozen soil variable stiffness road bridge transition structure and a construction process of the frozen soil variable stiffness road bridge transition structure, which can meet the variable stiffness requirement of a roadbed at a road bridge transition section, ensure the stability of the roadbed, prevent the roadbed from breaking and sliding, and have a cooling protection effect on a frozen soil foundation layer.

Embodiments of the present invention are implemented as follows:

in a first aspect, the invention provides a frozen soil variable stiffness road bridge transition structure, comprising:

the bridge abutment and the roadbed are arranged on the foundation layer;

The roadbed comprises:

The graded broken stone cushion layer is arranged on the foundation layer;

The reinforced concrete retaining wall is provided with a plurality of filling areas which are distributed at intervals in the extending direction of the roadbed;

The block gravel packing layers are arranged in the filling areas, a slope is arranged on one side of the block gravel packing layers, which is away from the graded gravel cushion layer, and the height of the slope is gradually reduced in the direction from one side close to the bridge abutment to one side far from the bridge abutment;

A fill layer disposed on the ramp;

and the rigid access board is arranged between the filling layer and the bridge abutment, is borne by the block broken stone filling layer and is connected with the bridge abutment.

In an alternative embodiment, the reinforced concrete retaining wall comprises a framed wall comprising a heel plate and a plurality of first wall panels connected to the heel plate, the height of the plurality of first wall panels gradually decreasing in a direction from a side proximate to the abutment to a side distal from the abutment, the heel plate and the plurality of first wall panels together defining a plurality of fill areas.

In an alternative embodiment, the frame wall further comprises two second wall panels with equal heights, wherein the two second wall panels are connected with the heel plate, the two second wall panels are located on one side, close to the bridge abutment, of the first wall panels, which are highest in height, of the first wall panels, the two second wall panels are provided with a distance in the extending direction of the roadbed, and the second wall panel, away from the first wall panel, of the two second wall panels is connected with the bridge abutment.

In an alternative embodiment, the block stone filler layer comprises a block stone filler layer and a stone leveling layer, the block stone filler layer is arranged in the plurality of filling areas, and the stone leveling layer is arranged on the block stone filler layer and is positioned between the two second wall panels;

the rigid access panel is simultaneously carried by the crushed stone screed and the two second wall panels.

In an alternative embodiment, a tie bar is provided between at least two of the plurality of wall panels of the framed wall.

In an alternative embodiment, the graded broken stone cushion layer comprises a first-stage crushed stone cushion layer, a first geogrid layer, a second graded broken stone cushion layer, a second geogrid layer and a third-stage crushed stone cushion layer which are sequentially arranged from bottom to top.

In an alternative embodiment, the abutment comprises a abutment base, an abutment body and an abutment top which are sequentially arranged from bottom to top, the abutment base is used for being connected with the foundation layer, and a part of the abutment base is connected with one side of the graded broken stone cushion layer, which is far away from the reinforced concrete retaining wall.

In an alternative embodiment, a concrete backfill layer is provided between the bench foundation and the graded crushed stone cushion layer.

In an alternative embodiment, the abutment is pre-embedded with a first connecting bar, the rigid access panel is provided with a second connecting bar, and the first connecting bar is connected with the second connecting bar through a threaded sleeve.

In a second aspect, the invention provides a construction process of a frozen soil variable stiffness road bridge transition structure, which comprises the following steps:

paving a graded broken stone cushion layer on a ground layer provided with a bridge abutment;

Setting a reinforced concrete retaining wall with a plurality of filling areas on the graded broken stone cushion layer, wherein the reinforced concrete retaining wall is abutted with the bridge abutment;

setting block broken stone filling layers in a plurality of filling areas, and enabling one side of the block broken stone filling layers, which is far away from the bridge abutment, to form a slope;

setting a filling layer on the slope;

And a rigid access board is arranged between the filling layer and the bridge abutment, and is simultaneously borne by the reinforced concrete retaining wall and the block broken stone filling layer, so that the rigid access board is fixedly connected with the bridge abutment.

The embodiment of the invention has the beneficial effects that:

In summary, the frozen soil variable stiffness road bridge transition structure provided by the embodiment forms a slope structure at the joint of the block broken stone filler layer and the filler layer, so that the variable stiffness connection between the bridge abutment at the road bridge transition position and the roadbed is realized, the step compaction settlement caused by different stiffness between the bridge abutment and the roadbed is avoided, and the road surface dynamic load is uniformly transmitted to the roadbed by combining with the mode that the rigid butt strap is arranged at the abutment back of the bridge abutment, the breaking or regional compaction of the block broken stone filler layer is avoided, and the uneven settlement of the road surface due to the stiffness shock and the block broken stone compaction effect under the action of the long-term dynamic load can be effectively prevented. Compared with a common filling layer, the block broken stone filling layer can greatly dissipate dynamic stress generated when a train passes, so that adverse effects on a roadbed structure are effectively reduced, and the stability and service life of a roadbed are increased.

Meanwhile, the block broken stone filler layer has good heat shielding and cold exchange effects on the permafrost region foundation, can realize cooling protection on the permafrost foundation, prevents the permafrost foundation from melting and settling, and further improves the problems of roadbed collapse and uneven pavement settlement. Meanwhile, the block broken stone packing layer ladder with the slope structure is arranged on the side face of the road bridge transition section, so that the problem that the area of a concrete panel is overlarge and heat absorption is excessive is solved, the average temperature in a frozen soil foundation is reduced through the cooling effect of the block broken stone packing layer, and the frozen soil protection is realized. Meanwhile, the heat shielding effect of the block broken stone filler layer can also prevent strong water erosion effect of water flow under the bridge on the frozen soil foundation, and the frozen soil is prevented from being in a long-term unstable state.

And in the filling area that reinforced concrete props up the barricade and constitutes, the dynamic load that acts on the road bed transmits to reinforced concrete props up barricade and piece rubble filler layer in locating the piece rubble filler layer, because reinforced concrete props up the barricade and has the constraint effect to piece rubble filler layer, can improve piece rubble filler layer phenomenon of sliding to improve the road bed subsidence phenomenon, and then improve the stability of road bed.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic structural diagram of a frozen soil variable stiffness road bridge transition structure according to an embodiment of the invention;

FIG. 2 is a schematic cross-sectional structure diagram of a frozen soil variable stiffness road bridge transition structure according to an embodiment of the invention;

fig. 3 is a schematic perspective view of a bridge transition structure according to an embodiment of the present invention;

Fig. 4 is a schematic structural view of a reinforced concrete retaining wall according to an embodiment of the present invention;

fig. 5 is a schematic view of a portion of a reinforced concrete retaining wall according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of an abutment and rigid access panel according to an embodiment of the present invention;

fig. 7 is a schematic view of a part of a connection structure of an abutment and a rigid access board according to an embodiment of the present invention.

Icon:

001-foundation layer, 101-first bearing surface, 102-second bearing surface, 100-bridge abutment, 110-foundation, 111-upper platform, 112-lower platform, 120-bench, 130-bench top, 140-concrete backfill layer, 150-first connecting steel bar, 160-threaded sleeve, 200-roadbed, 300-graded broken stone cushion layer, 400-reinforced concrete retaining wall, 410-frame wall, 411-heel plate, 412-first wall plate, 413-second wall plate, 420-opposite-pulling steel bar, 430-filling area, 440-grouting sleeve, 441-grouting opening, 442-grout outlet, 450-reserved steel bar, 500-broken stone filler layer, 510-slope, 520-block stone filler layer, 530-broken stone leveling layer, 600-filled earth layer, 700-rigid board, 710-second connecting steel bar and 800-ventilation pipe.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that like reference numerals and letters refer to like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present invention, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal," "vertical," and the like do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present invention, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected through an intermediary, or in communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

Referring to fig. 1-7, the embodiment provides a frozen soil rigidity-variable road bridge transition structure, which is not easy to generate large-scale settlement during service, has high use safety and long service life.

Referring to fig. 1 and 2, in the present embodiment, the frozen soil variable stiffness road bridge transition structure includes a bridge abutment 100 and a roadbed 200 for being disposed on a foundation layer 001, wherein the foundation layer 001 is a frozen soil foundation layer 001.

The roadbed 200 comprises a graded broken stone bedding layer 300 arranged on a foundation layer 001, a reinforced concrete retaining wall 400 arranged on the graded broken stone bedding layer 300, a block broken stone filler layer 500, a filler layer 600 arranged on a slope 510 and a rigid butt strap 700 arranged between the filler layer 600 and the bridge abutment 100. The reinforced concrete retaining wall 400 is provided with a plurality of filling areas 430 arranged at intervals in the extending direction of the roadbed 200, and the reinforced concrete retaining wall 400 is connected to the abutment 100. The block gravel packing layer 500 is provided in the plurality of filling areas 430, a slope 510 is provided at a side of the block gravel packing layer 500 facing away from the graded gravel bed 300, and the height of the slope 510 is gradually reduced in a direction from a side near the abutment 100 to a side far from the abutment 100, and the rigid butt strap 700 is carried by the block gravel packing layer 500 and connected with the abutment 100.

The frozen soil variable stiffness road bridge transition structure provided by the embodiment has the beneficial effects that:

The frozen soil rigidity-variable road bridge transition structure provided by the embodiment mainly realizes the slow change of the rigidity of the road bridge transition section by combining the block gravel packing layer 500 and the filling layer 600, and the block gravel packing layer 500 is reinforced by adopting the reinforced concrete supporting wall 400, so that the problem that the block gravel packing layer 500 is easy to slide sideways under the action of long-term dynamic load is solved, and the heat absorption of the foundation layer 001 is reduced by reducing the surface area of a concrete plate, thereby achieving the purpose of protecting the frozen soil foundation layer 001. Meanwhile, the frozen soil rigidity-changing road bridge transition structure prevents the frozen soil foundation from melting and settling by utilizing the cooling effect of the block broken stone filler layer 500, further protects the frozen soil for many years and effectively solves the problem of bridge head jump caused by uneven settlement of the road surface.

Referring to fig. 1, in this embodiment, it should be understood that the foundation layer 001 includes two bearing surfaces with a height difference, the two bearing surfaces are both disposed horizontally, the height of the first bearing surface 101 is lower than that of the second bearing surface 102, and the first bearing surface 101 and the second bearing surface 102 are connected by a vertical surface.

Referring to fig. 3, in the present embodiment, before setting the roadbed 200, the bridge abutment 100 is laid on the first bearing surface 101. The bridge deck 100 includes a deck base 110, a deck body 120, and a deck top 130 sequentially disposed from bottom to top, the deck base 110 being configured to be coupled to a first bearing surface 101 of a foundation layer 001.

Alternatively, the cross section of the table base 110 is "T" shaped, in other words, the table base 110 includes an upper table 111 and a lower table 112, and the width of the upper table 111 in the extending direction of the roadbed 200 is smaller than the width of the lower table 112 in the length direction of the roadbed 200, so that the cross section of the table base 110 is "T" shaped. After the table foundation 110 is fixed to the first bearing surface 101, there is a height difference between the lower table 112 and the second bearing surface 102, and a concrete backfill layer 140 is provided on one side of the lower table 112 and the upper table 111 close to the second bearing surface 102. The top surface of the concrete backfill layer 140 is in the same plane as the second load bearing surface 102.

The table body 120 is fixed on the top surface of the upper table 111, and the first connecting steel bars 150 are embedded on one side of the table top 130 close to the second bearing surface 102. The first connection reinforcement 150 is used to connect with the rigid access panel 700.

Further, the abutment foundation 110 is made of C50 reinforced concrete, the rest of the abutment 100 is made of C35 reinforced concrete, the free fall of the concrete is ensured to be not more than 2m by adopting a through long guide pipe string cylinder in the casting process, and the thickness of each layer is not more than 30cm by adopting a layered casting method, so that the impact of the concrete in the casting process is reduced, and the compressive strength of the abutment 100 is ensured.

Referring to fig. 6 and 7, further, a first connection bar 150 with a length of 1.5m is provided on the right side of the abutment 130 of the bridge abutment 100 along the extending direction of the roadbed 200 for connecting the rigid access board 700, the first connection bar 150 is a Φ8 screw-type bar with a spacing of 200mm, and the concrete backfill layer 140 is formed by backfilling C15 plain concrete.

In this embodiment, optionally, the graded broken stone bedding 300 is used to be laid on the second bearing surface 102, the thickness of the graded broken stone bedding 300 is set to be 50cm, after the graded broken stone bedding 300 is laid, the graded broken stone bedding 300 is connected with the upper table 111 and the concrete backfill layer 140, and the top surface of the graded broken stone bedding 300 and the top surface of the upper table 111 are located in the same plane, that is, the top surface of the graded broken stone bedding 300 is equal to the top surface of the upper table 111. The graded crushed stone bedding 300 is mainly formed by stacking crushed granite with good water permeability and a grain size of 5-6 cm. The compression strength of the graded broken stone layer is not less than 80MPa, the crushing value is not less than 35%, the content of weak particles is less than 5%, the mud content is less than 2%, the content of flat slender broken stone is less than 20%, and the compaction coefficient is not less than 0.95.

Further, the graded broken stone layer comprises a first graded broken stone cushion layer 300, a first geogrid layer, a second graded broken stone cushion layer 300, a second geogrid layer and a third graded broken stone cushion layer 300 which are sequentially laminated from bottom to top, wherein the first graded broken stone cushion layer 300, the second graded broken stone cushion layer 300 and the third graded broken stone cushion layer 300 are all paved in a mode of mechanical rolling after manual paving, and the height difference after rolling is not more than +/-15 mm. The lap joint length of the first geogrid layer and the second geogrid layer is more than 30cm, the tensile strength is not less than 25MPa, and the tensile modulus is not less than 650MPa.

Referring to fig. 4, in the present embodiment, an optional reinforced concrete retaining wall 400 includes a frame wall 410 and opposite-pulling steel bars 420. The frame wall 410 includes a heel plate 411 and a plurality of wall panels connected to the heel plate 411, wherein the wall panels are perpendicular to the heel plate 411, and the adjacent wall panels have equal spacing in the extending direction of the roadbed 200.

Optionally, the plurality of wall panels includes a plurality of first wall panels 412 and two second wall panels 413, the height of the plurality of first wall panels 412 gradually decreases in a direction from a side closer to the bridge deck 100 to a side farther from the bridge deck 100, and the heel panel 411 and the plurality of first wall panels 412 together define a plurality of filling areas 430. The two second wall panels 413 are located at the side of the highest first wall panel 412 close to the bridge abutment 100, the two second wall panels 413 have a distance in the extending direction of the roadbed 200, the second wall panel 413 far away from the first wall panel 412 in the two second wall panels 413 is attached to and connected with the abutment 120 of the bridge abutment 100, and the two second wall panels 413 and the heel panel 411 together define a filling area 430. Heel plate 411 is laid on graded crushed stone bed 300 and connected to a part of the top surface of upper table 111.

It should be appreciated that the lowest first wall panel 412 of the plurality of first wall panels 412 is spaced from the side of the heel panel 411 remote from the bridge 100, the lowest first wall panel 412 and heel panel 411 forming a right triangular fill area 430.

The number of the opposite-pull reinforcing bars 420 is set as required, and at least one opposite-pull reinforcing bar 420 is arranged between two adjacent wall panels, thereby enhancing the structural stability of the reinforced concrete retaining wall 400.

Referring to fig. 5, in the present embodiment, it should be noted that the reinforced concrete retaining wall 400 is prefabricated and can be transported to the site for assembly after being prefabricated in a factory. For example, the reinforced concrete retaining wall 400 is connected by using a full grouting sleeve 440, i.e. the grouting sleeve 440 is threaded, then the reserved steel bars 450 to be connected are sleeved with threads, the reserved steel bars 450 are connected with the sleeve through threads, and finally grouting material is poured. It should be understood that the grouting sleeve 440 is provided with a grouting port 441 and a grouting port 442, and grouting material is injected from the grouting port 441.

Further, the heel plate 411 and the wall panel are both set to 160mm wall thickness according to the second-level requirement of the earthquake-proof level, phi 16 screw steel is uniformly arranged in the wall according to the interval of 200mm and hoops are arranged, the reinforcement ratio of the horizontally and vertically distributed reinforcements is not less than 0.2%, and long reinforcements of 30cm are reserved in advance according to the positions of the opposite-pull reinforcements 420 so as to be in anchoring connection. The heel plate 411 has a length of 100m in the extending direction of the roadbed 200.

Further, the opposite-pulling steel bars 420 are Q235 smooth round steel bars, the diameter is 12mm, the height direction is arranged at equal intervals of 1m, and the number of the opposite-pulling steel bars 420 in each row is gradually decreased from bottom to top.

In this embodiment, optionally, each filling area 430 is filled with a block gravel packing layer 500, and the block gravel packing layers 500 in the plurality of filling areas 430 form a structure with an outer contour substantially in a right trapezoid shape. Wherein, the upper bottom of the right trapezoid is away from the graded broken stone filling cushion layer, the lower bottom is contacted with the heel plate 411, and optionally, the length of the upper bottom is 10m, and the length of the lower bottom is 100m. The upper bottom is formed between the filling areas 430 formed by the two second wall panels 413 and the upper surfaces of the two second wall panels 413 are at the same level, i.e., the upper bottom and the upper surfaces of the two second wall panels 413 are in the same plane for supporting the rigid access panel 700.

Referring to fig. 3, optionally, the block stone filler layer 500 includes a block stone filler layer 520 and a stone leveling layer 530, the block stone of the block stone filler layer 520 has a maximum particle diameter of not more than 150mm, a compaction thickness of not more than 30cm per layer, a settlement amount after compaction of less than 3mm, and a porosity of not more than 28%. The thickness of the crushed stone leveling layer 530 is 20cm, and 5-6 cm crushed stone is used for filling and compacting. The gravel leveling layer 530 is disposed on top of the stone filler layer 520, and the top surface of the gravel leveling layer 530 is the upper bottom of the stone filler layer 500, that is, the top of the stone filler layer 520 between the two second wall panels 413, and together with the second wall panels 413, supports the rigid bridge 700.

In this embodiment, the filling layer 600 uses mixed soil and sand clay with fine particle content less than 30% as the filling material, and the maximum compaction thickness of each layer is not more than 20cm, and the slope is laid by adopting a slope ratio of 1:1.5. After the filling layer 600 is paved, the top surface of the filling layer 600 is higher than the top surface of the crushed stone leveling layer 530, and a rectangular groove for clamping the rigid butt strap 700 is formed between the filling layer 600 and the table top 130.

In this embodiment, alternatively, the length of the rigid access board 700 is set to 10m, the thickness of the access board is not less than 30cm, the second connecting steel bars 710 with the interval of 200mm and the diameter of 8mm are arranged in the board, the rigid access board 700 is arranged on the gravel leveling layer 530 and is simultaneously contacted with two second wall panels 413, two sides of the rigid access board 700 in the extending direction of the roadbed 200 are respectively connected with the bench top 130 and the filling layer 600, and the second connecting steel bars 710 on the rigid access board 700 are connected with the first connecting steel bars 150 on the bench top 130 through the threaded sleeves 160 and are poured by adopting C30 concrete.

It will be appreciated that at the bridge transition, the road surface at that section may be approximated as an arc due to the small change in pitch, and that centripetal acceleration may occur as the vehicle passes. Assuming that M is the weight of the vehicle, the centripetal force is f=mv ² +.r=μmg, when μ=0.1, the car is in critical skip state, and r=mv ²÷F＝v² +.mu.g can be deduced. Assuming that the slope rate of the rigid butt strap 700 is i and the slope is α approximately equal to i, it can be deduced that the critical vehicle-jumping longitudinal slope rate of the vehicle is i=l/r=l/v ², and it can be seen that the running speed of the vehicle and the length of the rigid butt strap 700 both affect the vertical curve radius and the slope change rate of the critical vehicle-jumping state, the length of the rigid butt strap 700 is unchanged, the critical vehicle-jumping longitudinal slope change slope rate is reduced along with the increase of the speed, and the vehicle is very easy to jump. Therefore, the length of the rigid access board 700 should be increased as the road grade becomes higher, and should not be shorter than 8m in general, and in this embodiment, the length of the rigid access board 700 is selected to be 10m to improve the road surface condition and the driving safety.

It should be appreciated that after the rigid access panel 700 is installed, the top surface of the rigid access panel 700 is flush with the top surface of the fill layer 600.

In other embodiments, a plurality of ventilation pipes 800 are embedded in the stone filler layer 520, the ventilation pipes 800 extend along the width direction of the roadbed 200, and both ends of the ventilation pipes 800 are open.

The frozen soil rigidity-variable road bridge transition structure provided by the embodiment has the advantages of high structural stability, long service time, safety and reliability.

The embodiment also provides a construction process of the frozen soil variable-rigidity road bridge transition structure, which comprises the following steps:

A. Before the roadbed 200 is started, three-way leveling should be realized, the natural earth surface in the planning range of the roadbed 200 is processed in a rolling mode, meanwhile, measurement routing work is carried out, and the measurement precision is standard according to the requirements of the highway route survey procedure.

B. And paving a first-stage matched gravel cushion layer 300 on the treated natural ground surface by adopting a mode of firstly manually paving and then mechanically compacting, measuring the flatness of the graded gravel cushion layer 300 to meet the requirements of the technical specification of construction of the highway subgrade 200, and then paving a geogrid. And (5) sequentially paving the second graded broken stone cushion layer 300 and the third graded broken stone cushion layer 300 from bottom to top by repeating the steps, and compacting.

C. After the reinforced concrete retaining wall 400 is transported to the construction site, the reinforced concrete retaining wall is assembled in a threaded sleeve connection mode as required. Firstly, installing a steel bar positioning fixture and fixing seven character codes along the inner edge of the prefabricated wall body, conveniently guiding the prefabricated assembly to fall, and observing whether the steel bars of the prefabricated assembly are aligned with the grouting sleeve 440 by adopting a mirror. After the completion of the landing, adjust prefabricated wall body's straightness and fixed bearing diagonal through the bearing diagonal, then block up the regional wall body inboard of grout immediately, ensure to block up mortar before the grout and reach the design strength grade, avoid simultaneously causing the pollution to the grout region. After the mortar is blocked for 4 hours, mechanical continuous grouting is adopted, and a test block is reserved according to the standard requirement.

D. After the maintenance of the installed reinforced concrete retaining wall 400 is completed, opposite-pull steel bars 420 are arranged in the wall panel, and two ends of the opposite-pull steel bars 420 are respectively connected with reserved steel bars 450 of the wall panel of the reinforced concrete retaining wall 400 in an anchoring manner.

E. The reinforced concrete retaining wall 400 is filled with crushed stone filler and compacted in layers as required, the thickness of each layer is not more than 30cm, and the crushed stone leveling layer 530 with the thickness of 20cm is paved finally. After the block broken stone filler is transported to a construction site, measuring and paying off are carried out, firstly, manually paving, then, rough leveling is carried out by adopting an excavator, then, the excavator is used for carrying out track displacement and pressing for one time, then, a loader is matched with manual broken stone fine materials to fill stone gaps, and then, a vibratory roller is used for rolling for 4-6 times until the compaction standard is met, and then, the next layer of paving is carried out.

F. The filling layer 600 adopts layered paving roadbed 200 filling, the paving height of each layer is controlled to be 25cm, and the filling layer is compacted for 5-6 times by using a vibratory roller after being compacted for one time by using a steel wheel roller. Before each layer of construction, the upper layer of solid filling soil needs to be sprayed with water for wetting, so that the roadbed 200 is prevented from being damaged, and dust pollution is reduced.

G. Binding steel bars on the upper layer of the block gravel subgrade 200, connecting the left side with reserved steel bars 450 through threaded sleeves 160, casting according to the panel size formwork of the rigid butt strap 700 by adopting C30 concrete, and curing for 14 days after casting is completed.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a frozen soil becomes rigidity road bridge transition structure which characterized in that includes:

Bridge abutment and roadbed on the frozen ground base layer;

The roadbed comprises:

the graded broken stone cushion layer is arranged on the frozen ground base layer;

The reinforced concrete retaining wall is arranged on the graded broken stone cushion layer and is provided with a plurality of filling areas which are distributed at intervals in the extending direction of the roadbed;

the block gravel packing layers are arranged in the filling areas, a slope is arranged on one side of the block gravel packing layers, which is away from the graded gravel cushion layer, and the height of the slope gradually decreases in the direction from one side close to the bridge abutment to one side far away from the bridge abutment;

A fill layer disposed on the ramp;

the rigid access board is arranged between the filling layer and the bridge abutment, is borne by the broken stone filling layer and is connected with the bridge abutment;

The reinforced concrete retaining wall comprises a frame type wall body, wherein the frame type wall body comprises a heel plate and a plurality of first wall panels connected with the heel plate, the heights of the first wall panels gradually decrease in the direction from one side close to the bridge abutment to one side far away from the bridge abutment, and the heel plate and the first wall panels jointly define a plurality of filling areas;

The frame type wall body further comprises two second wall panels with equal heights, the two second wall panels are connected with the heel plate, the two second wall panels are located at one side, close to the bridge abutment, of the first wall panels, the first wall panels are located at the highest height, the two second wall panels are spaced in the extending direction of the roadbed, and the second wall panel, far away from the first wall panel, of the two second wall panels is connected with the bridge abutment;

the block stone filling layer comprises a block stone filling layer and a stone leveling layer, the block stone filling layer is arranged in the filling areas, and the stone leveling layer is arranged on the block stone filling layer and is positioned between the two second wall panels;

The rigid access board is simultaneously borne by the broken stone leveling layer and the two second wall panels;

the abutment comprises a abutment base, an abutment body and an abutment top which are sequentially arranged from bottom to top, wherein the abutment base is used for being connected with the foundation layer, and a part of the abutment base is connected with one side, far away from the reinforced concrete retaining wall, of the graded broken stone cushion layer.

2. The frozen soil variable stiffness road bridge transition structure of claim 1, wherein:

and opposite-pull reinforcing steel bars are arranged between at least two of the plurality of wall panels of the frame type wall body.

3. The frozen soil variable stiffness road bridge transition structure of claim 1, wherein:

The graded broken stone cushion layer comprises a first-stage crushed stone cushion layer, a first geogrid layer, a second graded broken stone cushion layer, a second geogrid layer and a third-stage crushed stone cushion layer which are sequentially arranged from bottom to top.

4. The frozen soil variable stiffness road bridge transition structure of claim 1, wherein:

and a concrete backfill layer is arranged between the platform foundation and the graded broken stone cushion layer.

5. The frozen soil variable stiffness road bridge transition structure of claim 1, wherein:

The bridge abutment is embedded with first connecting steel bars, the rigid butt strap is provided with second connecting steel bars, and the first connecting steel bars are connected with the second connecting steel bars through threaded sleeves.

6. The construction process of the frozen soil variable-rigidity road bridge transition structure is characterized by comprising the following steps of:

setting a reinforced concrete retaining wall with a plurality of filling areas on the graded broken stone cushion layer, wherein the reinforced concrete retaining wall is abutted with the abutment;

Setting a block gravel packing layer in the filling areas, and enabling one side of the block gravel packing layer far away from the bridge abutment to form a slope;

Setting a filling layer on the slope;

And a rigid access board is arranged between the filling layer and the bridge abutment, and is simultaneously borne by the reinforced concrete retaining wall and the block broken stone filler layer, so that the rigid access board is fixedly connected with the bridge abutment.