CN108664754B - Method for calculating buffer layer elastic modulus from buffer layer compactness - Google Patents

Abstract

The invention discloses a method for calculating the elastic modulus of a buffer layer from the compactness of the buffer layer. Uniformity coefficient Cu and soil-rock density S, soil-rock particle non-uniformity coefficient Cu is calculated by formula 1; soil-rock particle non-uniformity coefficient Cu includes three grades, uniform grade, basic uniform grade and non-uniform grade. The uniformity coefficient Cu is used to judge the grade; b. Calculate the soil-rock density S by formula 2; c. Calculate the soil-rock elastic modulus M according to the soil-rock density S. The invention fully considers the influence of the specific compactness of soil and rock on the elastic modulus, and the calculation method is suitable for the actual calculation of the large-scale rough rock buffer layer in the field. disaster prevention applicability.

Description

A method for calculating the elastic modulus of the buffer layer from the compactness of the buffer layer

technical field

The invention relates to the field of collapse and rockfall prevention and control engineering, in particular to a method for calculating the elastic modulus of a buffer layer from the compactness of the buffer layer.

Background technique

Collapse and rockfall are natural phenomena that occur in mountainous areas or on highway slopes. After the collapse and rockfall, huge stones roll down the hillside or roadside, causing great damage to nearby residential buildings, factories and other construction facilities, or roads, etc. In order to slow down the impact of the impact force, it is an economical and effective measure to take the soil-rock buffer layer for effective protection. The most economical and applicable buffer layer is composed of stone, sand, soil and other materials, and is composed of one or more of them. Therefore, the particle size of different soil-rock buffer layers has different buffer effects, and the buffer effect can be determined by the buffer layer. The elastic modulus of the layer is expressed. At present, the research on the elastic modulus of soil-rock buffer layer at home and abroad is relatively rough, only considering the range of several particle sizes, softness, hardness and compactness, and giving the corresponding elastic modulus range. This particle size range is not only rough, but also the specific particle size range is not clearly defined. It is difficult to determine its range in practical applications, and it cannot meet the actual needs: when the available earth and stone materials on the actual construction site are relatively coarse, such as relatively large Rocks larger than the particle size of pebbles will exceed the given range of the elastic modulus of the current soil and rock. It is impossible to determine the value of the elastic modulus, and it is impossible to judge whether it can meet the requirements of reducing the impact force of rolling stones, or waste manpower and material resources. .

The publication number is CN 104360389A, and the Chinese patent document with the publication date of February 18, 2015 discloses a method for calculating the elastic modulus of tight sandstone reservoir rock, which is characterized in that it includes: obtaining logging parameters and information about tight sandstone reservoirs. rock physical property parameters; according to the logging parameters and the rock physical property parameters, combined with the pre-established pore fracture attenuation model to calculate the rock elastic modulus under high frequency; according to the rock elastic modulus under the high frequency, combined with the pre-established The self-consistent model of the rock is used to calculate the high-frequency matrix elastic modulus of the rock; the elastic modulus of the saturated rock at any frequency is calculated using the high-frequency matrix elastic modulus of the rock, combined with the pore and fracture attenuation model.

The method for calculating elastic modulus of tight sandstone reservoirs disclosed in this patent document is based on the characteristics of porosity of tight sandstone reservoirs, using established petrophysical models suitable for tight sandstone reservoirs, such as: pore fracture attenuation model and self-consistent The model analyzes the tight sandstone reservoir and obtains the rock elastic modulus of the tight sandstone reservoir. However, since the influence of the specific compactness of tight sandstone reservoir rocks on the elastic modulus is not considered, its calculation method is not suitable for the actual calculation of large-scale rough rock buffer layers in the field, and is suitable for disaster prevention and mitigation of collapse and rockfall. Poor sex.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned defects of the prior art, the present invention provides a method for calculating the elastic modulus of the buffer layer from the compactness of the buffer layer. The present invention fully considers the influence of the specific compactness of soil and rock on the elastic modulus, and the calculation method is suitable for field use. The actual calculation of large-scale rough rock buffer layer is accurate and reliable, and it has higher disaster prevention applicability for disaster prevention and mitigation of collapse and rockfall.

The present invention is achieved through the following technical solutions:

A method for calculating the elastic modulus of a buffer layer from the compactness of the buffer layer, comprising the following steps:

a. Measure and obtain the characteristic parameters of soil-rock buffer layer particles, including the median particle size of soil and rock D, soil-rock particle heterogeneity coefficient Cu and soil-rock density S, and the median soil-rock particle size D refers to the particle size of 50% by weight of soil and rock particles , unit mm; soil-rock particle unevenness coefficient Cu is calculated by formula 1; soil-rock particle unevenness coefficient Cu includes three grades, uniform grade, basic uniform grade and uneven grade, and soil-rock particle unevenness coefficient Cu≤5 is a uniform grade; The particle non-uniformity coefficient 5<Cu≤10 is the basic uniform grade; the soil-rock particle non-uniformity coefficient Cu>10 is the non-uniform grade, and the soil-rock particle non-uniformity coefficient Cu calculated by formula 1 is used to judge the grade;

Cu=D ₆₀ /D ₁₀ formula 1

In the formula, D ₆₀ is the particle size of 60% by weight of soil-rock particles, in mm; D ₁₀ is the particle size of 10% by weight of soil-rock particles, in mm;

b. Calculate the soil-rock density S by formula 2;

S=V _m /V Formula 2

where V _m is the minimum volume of soil and rock, in m ³ ; V is the actual volume of soil and rock, in m ³ ;

c. Calculate the soil-rock elastic modulus M according to the soil-rock density S;

When the median particle size of soil and rock D≥2mm, it is gravel, pebbles or coarse soil and rock, which is calculated by formula 3;

M=C ₁ S ^4.3 Equation 3

When the median particle size of soil and rock is 0.02mm≤D<2mm, it is sand and gravel, which is calculated by formula 4;

M=C ₂ S ^4.3 Equation 4

When the median particle size of soil and rock D<0.02mm, it is sandy clay containing 10%-50% clay, which is calculated by formula 5;

M=46.3S ^3.6 Equation 5

Among them, M is the elastic modulus of soil and rock, in MPa; S is the density of soil and rock; C ₁ and C ₂ are both coefficients.

The C ₁ and C ₂ are determined through a value table according to the soil-rock particle inhomogeneity coefficient Cu grade and the soil-rock median particle size D.

The basic principle of the present invention is as follows:

The elastic modulus of the soil-rock in the buffer layer is related to the particle size of the soil-rock particles, as well as the particle size distribution of the soil-rock particles and the compactness of the soil-rock buffer layer. The size and characteristics of these physical quantities determine the elastic modulus of the soil-rock buffer layer, and also determine the ability and characteristics of the soil-rock buffer layer to buffer impact force.

The invention studies the relationship between the particle size of the soil-rock buffer layer and the elastic modulus of the soil-rock buffer layer through a large number of experimental studies and theoretical derivation. According to the research results at home and abroad: the impact force of rolling stone is related to the mass, velocity, elastic modulus of the impacting object, the moving direction of the impacting object and the plane angle of the impacted object, as well as the elastic modulus of the impacted object. These physical quantities determine the magnitude of the impact force of the rolling stone.

When the impacted object is a soil-rock buffer layer, the magnitude of the elastic modulus of the soil-rock buffer layer is 0.3-200 MPa, which is much smaller than that of the rolling stone, which is on the order of 5,000-80,000 MPa. The relationship between the elastic modulus of the soil-rock buffer layer and the elastic modulus of the rolling stone is as follows:

Among them, E is the comprehensive elastic modulus, in MPa; E ₁ is the elastic modulus of rolling stone, in MPa; E ₂ is the elastic modulus of the soil-rock buffer layer, in MPa.

The elastic modulus that ultimately affects the impact force is the comprehensive elastic modulus E. When the elastic modulus of the rolling stone is much larger than the elastic modulus of the soil-rock buffer layer, the elastic modulus of the rolling stone can be ignored, and only the elastic modulus of the soil-rock buffer layer can be used to calculate the impact force of the rolling stone on the buffer layer and the building protected by the buffer layer. , and the impact force is much smaller than the impact force of the rolling stone directly impacting the building without the buffer layer, and decreases with the decrease of the elastic modulus of the buffer layer.

The beneficial effects of the present invention are mainly manifested in the following aspects:

1. In the present invention, "a. The characteristic parameters of soil-rock buffer layer particles are obtained by measuring and calculating, including the median particle size of soil and rock D, the nonuniformity coefficient Cu of soil and rock particles and the compactness S of soil and rock. The median particle diameter of soil and rock D refers to the weight percentage in the soil and rock particles. 50% particle size, unit mm; soil-rock particle unevenness coefficient Cu is calculated by formula 1; soil-rock particle unevenness coefficient Cu includes three grades, uniform grade, basic uniform grade and uneven grade, soil-rock particle unevenness coefficient Cu≤ 5 is a uniform grade; soil-rock particle unevenness coefficient 5 <Cu≤10 is a basic uniform grade; soil-rock particle unevenness coefficient Cu>10 is a non-uniform grade, and the grade is judged by the soil-rock particle unevenness coefficient Cu calculated by formula 1; b. Pass Equation 2 calculates the soil-rock compaction S; c. Calculates the soil-rock elastic modulus M" according to the characteristic parameters of the soil-rock, fully considering the influence of the specific compactness of the soil-rock on the elastic modulus, and the calculation method is suitable for large-scale rough rock buffers in the field The calculation results are accurate and reliable, and it has higher applicability for disaster prevention and mitigation of collapse and rockfall.

2. In the present invention, the calculation of the elastic modulus of the soil-rock buffer layer considers the influence of the specific compactness of the soil and rock on the elastic modulus, so that the calculation results are more accurate, and it has better practical application significance for disaster prevention and mitigation of collapse and rockfall.

3. In the present invention, the calculation of the elastic modulus of the soil-rock buffer layer takes into account the soil-rock particle gradation, that is, the influence of the uniformity on the elastic modulus, so the accuracy and reliability of the calculation results are further improved, and the protection against collapse and rockfall It has better guiding significance for disaster prevention and mitigation in mountainous areas.

4. The present invention has different calculation methods for different soil-rock types in the soil-rock buffer layer, such as gravel and above coarse soil-rock, sand-stone type fine-grained soil-rock, and soil-rock containing clay, so that the calculation method of the elastic modulus of the soil-rock buffer layer is calculated. The accuracy is greatly improved, which can provide a reliable basis for the design of defensive impact measures.

Detailed ways

Example 1

A method for calculating the elastic modulus of a buffer layer from the compactness of the buffer layer, comprising the following steps:

a. Measure and obtain the characteristic parameters of soil-rock buffer layer particles, including the median particle size of soil and rock D, soil-rock particle heterogeneity coefficient Cu and soil-rock density S, and the median soil-rock particle size D refers to the particle size of 50% by weight of soil and rock particles , unit mm; soil-rock particle unevenness coefficient Cu is calculated by formula 1; soil-rock particle unevenness coefficient Cu includes three grades, uniform grade, basic uniform grade and uneven grade, and soil-rock particle unevenness coefficient Cu≤5 is a uniform grade; The particle non-uniformity coefficient 5<Cu≤10 is the basic uniform grade; the soil-rock particle non-uniformity coefficient Cu>10 is the non-uniform grade, and the soil-rock particle non-uniformity coefficient Cu calculated by formula 1 is used to judge the grade;

Cu=D ₆₀ /D ₁₀ formula 1

In the formula, D ₆₀ is the particle size of 60% by weight of soil-rock particles, in mm; D ₁₀ is the particle size of 10% by weight of soil-rock particles, in mm;

b. Calculate the soil-rock density S by formula 2;

S=V _m /V Formula 2

where V _m is the minimum volume of soil and rock, in m ³ ; V is the actual volume of soil and rock, in m ³ ;

c. Calculate the soil-rock elastic modulus M according to the soil-rock density S;

When the median particle size of soil and rock D≥2mm, it is gravel, pebbles or coarse soil and rock, which is calculated by formula 3;

M=C ₁ S ^4.3 Equation 3

When the median particle size of soil and rock is 0.02mm≤D<2mm, it is sand and gravel, which is calculated by formula 4;

M=C ₂ S ^4.3 Equation 4

When the median particle size of soil and rock D<0.02mm, it is sandy clay containing 10%-50% clay, which is calculated by formula 5;

M=46.3S ^3.6 Equation 5

Among them, M is the elastic modulus of soil and rock, in MPa; S is the density of soil and rock; C ₁ and C ₂ are both coefficients.

C ₁ is determined by the value table in Table 1:

Cu uniform basically uniform uneven uniform basically uniform uneven uniform basically uniform uneven D(mm) 2-10 10-50 50-200 10-50 50-200 2-10 50-200 2-10 10-50 C₁ 58.7 156.57 454.8 99.8 250.7 167.0 159.8 92.0 284.0

Table 1

C ₂ is determined by the value table of Table 2:

Table 2

"a. Measure and obtain the characteristic parameters of soil-rock buffer layer particles, including the median particle size of soil and rock D, soil-rock particle inhomogeneity coefficient Cu, and soil-rock density S, and the median soil-rock particle size D refers to the particles with a weight percentage of 50% in the soil and rock particles. diameter, in mm; the soil-rock particle non-uniformity coefficient Cu is calculated by formula 1; the soil-rock particle non-uniformity coefficient Cu includes three grades, uniform grade, basic uniform grade and non-uniform grade. The soil-rock particle unevenness coefficient of 5<Cu≤10 is the basic uniform grade; the soil-rock particle unevenness coefficient Cu>10 is the uneven grade, and the soil-rock particle unevenness coefficient Cu calculated by formula 1 is used to judge the grade; b. The soil-rock compaction is calculated by formula 2 c. Calculate the elastic modulus of soil and rock M” according to the characteristic parameters of soil and rock, fully considering the influence of the specific compactness of soil and rock on the elastic modulus, and the calculation method is suitable for the actual calculation of large-scale rough rock buffer layers in the field. The calculation results are accurate and reliable, and have higher applicability for disaster prevention and mitigation of collapse and rockfall.

Example 2

A method for calculating the elastic modulus of a buffer layer from the compactness of the buffer layer, comprising the following steps:

a. Measure and obtain the characteristic parameters of soil-rock buffer layer particles, including the median particle size of soil and rock D, soil-rock particle heterogeneity coefficient Cu and soil-rock density S, and the median soil-rock particle size D refers to the particle size of 50% by weight of soil and rock particles , unit mm; soil-rock particle unevenness coefficient Cu is calculated by formula 1; soil-rock particle unevenness coefficient Cu includes three grades, uniform grade, basic uniform grade and uneven grade, and soil-rock particle unevenness coefficient Cu≤5 is a uniform grade; The particle non-uniformity coefficient 5<Cu≤10 is the basic uniform grade; the soil-rock particle non-uniformity coefficient Cu>10 is the non-uniform grade, and the soil-rock particle non-uniformity coefficient Cu calculated by formula 1 is used to judge the grade;

Cu=D ₆₀ /D ₁₀ formula 1

In the formula, D ₆₀ is the particle size of 60% by weight of soil-rock particles, in mm; D ₁₀ is the particle size of 10% by weight of soil-rock particles, in mm;

b. Calculate the soil-rock density S by formula 2;

S=V _m /V Formula 2

where V _m is the minimum volume of soil and rock, in m ³ ; V is the actual volume of soil and rock, in m ³ ;

c. Calculate the soil-rock elastic modulus M according to the soil-rock density S;

When the median particle size of soil and rock D≥2mm, it is gravel, pebbles or coarse soil and rock, which is calculated by formula 3;

M=C ₁ S ^4.3 Equation 3

When the median particle size of soil and rock is 0.02mm≤D<2mm, it is sand and gravel, which is calculated by formula 4;

M=C ₂ S ^4.3 Equation 4

When the median particle size of soil and rock D<0.02mm, it is sandy clay containing 10%-50% clay, which is calculated by formula 5;

M=46.3S ^3.6 Equation 5

Among them, M is the elastic modulus of soil and rock, in MPa; S is the density of soil and rock; C ₁ and C ₂ are both coefficients.

The C ₁ and C ₂ are determined through a value table according to the soil-rock particle inhomogeneity coefficient Cu grade and the soil-rock median particle size D.

For the calculation of the elastic modulus of the soil-rock buffer layer, the influence of the specific compactness of the soil and rock on the elastic modulus is considered, which makes the calculation results more accurate, and has better practical application significance for disaster prevention and mitigation of collapse and rockfall.

For the calculation of the elastic modulus of the soil-rock buffer layer, the particle gradation of soil and rock, that is, the influence of uniformity on the elastic modulus, is considered, so the accuracy and reliability of the calculation results are further improved. have better guiding significance.

There are different calculation methods for different soil-rock types in the soil-rock buffer layer, such as gravel and above coarse soil-rock, sand-stone type fine-grained soil-rock, and soil-rock containing clay, which greatly improves the accuracy of calculating the elastic modulus of the soil-rock buffer layer. Therefore, it can provide a reliable basis for the design of anti-impact measures.

Claims (1)

1. A method for calculating the elastic modulus of a buffer layer according to the compactness of the buffer layer is characterized by comprising the following steps:

a. measuring and calculating to obtain characteristic parameters of the particles of the earth-rock buffer layer, wherein the characteristic parameters comprise the median diameter D of the earth-rock, the nonuniform coefficient Cu of the earth-rock particles and the compactness S of the earth-rock, and the median diameter D of the earth-rock refers to the particle diameter of 50% of the earth-rock particles in percentage by weight and is in unit mm; calculating the uneven coefficient Cu of the earth and stone particles by using formula 1; the uneven coefficient Cu of the soil and stone particles comprises three levels, namely a uniform level, a basic uniform level and an uneven level, wherein the uneven coefficient Cu of the soil and stone particles is not more than 5 and is the uniform level; the uneven coefficient of the earth and stone particles is more than 5 and less than or equal to 10, and the earth and stone particles are in a basic even level; the uneven coefficient Cu of the earth and stone particles is more than 10, and the level is judged according to the uneven coefficient Cu of the earth and stone particles calculated by the formula 1;

Cu＝D₆₀/D₁₀formula 1

In the formula, D₆₀The particle size is 60 percent of the particle size of the earth and stone particles by weight, and the unit is mm; d₁₀The particle size is 10 percent of the particle size of the earth and stone particles by weight, and the unit is mm;

b. calculating the density S of the earth and the stone by the formula 2;

S＝V_mv formula 2

In the formula, V_mIs the minimum volume of earth and stone, unit m³(ii) a V is the actual volume of earth and stone in m³；

c. Calculating the earth-rock elastic modulus M according to the earth-rock density S;

when the median particle diameter D of the earth and stone is more than or equal to 2mm, the earth and stone is gravel, pebble or coarse earth and stone, and the calculation is carried out by the formula 3;

M＝C₁S^4.3formula 3

When the median particle diameter D of the earth and the stone is more than or equal to 0.02mm and less than 2mm, the earth and the stone are taken as sandstone and are calculated by the formula 4;

M＝C₂S^4.3formula 4

When the median particle diameter D of the earth and the stone is less than 0.02mm, the earth and the stone are sandy clay containing 10-50% of clay, and the calculation is carried out according to the formula 5;

M＝46.3S^3.6formula 5

Wherein M is the earth and rock elastic modulus in MPa; s is the density of the earth and the stone; c₁And C₂Are all coefficients;

said C is₁And C₂And determining through a value taking table according to the inhomogeneous coefficient Cu grade of the earth and stone particles and the median diameter D of the earth and stone particles.