Stress calculation method for reinforced earth retaining wall with steel grid panel

Abstract

The present invention discloses a method for calculating the load of reinforced earth retaining walls with a simple concept and easy operation. The reinforced earth retaining wall is composed of earth fill, horizontally arranged ties, and grid panel units. The grid panel units include diagonal ties, vertical ties, and horizontal ties. The calculation method includes the following steps: Step 100, numbering the grid panel units from top to bottom and calculating the lateral earth pressure and ties tension acting on any grid panel unit layer based on the static equilibrium condition of the local soil wedge; Step 200, treating the grid panel unit structure as a primary statically indeterminate structure and calculating the axial force and cross-sectional normal stress of the diagonal ties of any grid panel unit layer; Step 300, calculating the axial force, bending moment, shear force, and cross-sectional normal stress of the vertical ties of any grid panel unit layer based on the static equilibrium condition; Step 400, calculating the axial force, bending moment, shear force, and cross-sectional normal stress of the horizontal ties of any grid panel unit layer based on the static equilibrium condition.

Description

Technical Field

[0001] The present invention relates to the technical field of force calculation of steel bar grid panel type reinforced earth retaining wall, in particular to a force calculation method of steel bar grid panel type reinforced earth retaining wall. Background Art

[0002] Backfill projects are a common type of construction project in areas such as roads, buildings, and municipal infrastructure. Stabilization and reinforcement measures for backfill projects are a key issue in practical engineering. Steel mesh panel reinforced earth retaining walls are a new technical approach that can address the stabilization and reinforcement issues of backfill projects. These structures offer advantages such as lightweight construction, ease of installation, cost-effectiveness, strong engineering adaptability, and low carbon environmental protection, making them promising for widespread application in practice. For steel mesh panel reinforced earth retaining walls, proper force calculation and analysis are a prerequisite for their actual engineering design, and are therefore of great significance for the rational design of these walls.

[0003] Under the weight of the fill and the top load of the fill, the steel mesh panels and reinforcement bars in the steel mesh panel reinforced earth retaining wall exhibit certain stress characteristics, and these stress characteristics vary along the height of the wall. Because this type of structure is relatively new, the current specifications do not include a calculation method for the stress of steel mesh panel reinforced earth retaining walls. As a result, related actual projects lack theoretical reference methods, and most of the design is based on experience, which is blind. Therefore, for steel mesh panel reinforced earth retaining wall structures, a more reasonable and simple stress calculation and analysis method is urgently needed in engineering practice.

[0004] At present, there are some calculation and analysis methods for ordinary reinforced earth retaining walls, but they are all aimed at classic integral panel and solid block wall panel structures. There is no force calculation and analysis method for reinforced earth retaining walls with steel grid panels as the main structure of the wall panels.

[0005] On the other hand, numerical simulation methods such as finite element and finite difference methods can be used for the stress calculation and analysis of reinforced earth retaining walls with steel mesh panels. However, numerical simulation methods first require the establishment of a numerical model, and the rationality of the numerical model depends on factors such as model parameters, model mesh accuracy, material constitutive model, and boundary conditions. Not only is the modeling process complex and cumbersome (especially difficult for densely distributed steel mesh wall panels), it is also subject to human subjective operation interference and is difficult to be "inherited" (different people need to start from the modeling operation). Although it can serve as a reference for the study of complex problems, it is not conducive to the rapid analysis and operation of actual engineering technicians.

[0006] Therefore, the current stress calculation and analysis of reinforced earth retaining walls with steel mesh panels lacks a simplified theoretical calculation method that is simple in concept and easy to operate in practice. This results in a lack of sufficient and reasonable basis for the specific application analysis of related engineering designs, or the calculation and analysis process is cumbersome. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a stress calculation method for a reinforced earth retaining wall with a steel grid panel structure that is simple in concept and easy to operate in practice.

[0008] In order to achieve the above-mentioned object, the present invention provides a force calculation method for a reinforced earth retaining wall with a steel grid panel, and the technical solution is as follows:

[0009] A stress calculation method for a reinforced earth retaining wall with a steel mesh panel is provided. The reinforced earth retaining wall with a steel mesh panel is composed of fill, horizontally arranged reinforcement bars, and a steel mesh panel structure. The steel mesh panel structure is composed of several layers of mesh panel units stacked sequentially from top to bottom. Each layer of mesh panel unit contains several diagonal tie bars, vertical bars, horizontal bars, and connecting bars therebetween. The reinforcement bars are connected and fixed to the steel mesh panel structure at each horizontal bar. The calculation method includes the following steps:

[0010] Step 100: number the grid panel units from top to bottom, and calculate the lateral earth pressure and reinforcement tension acting on any layer of grid panel units based on the static equilibrium condition of the local soil wedge;

[0011] Step 200 , regarding the grid panel unit structure as a primary statically indeterminate structure, the axial force and cross-sectional normal stress of the oblique tie rods of any layer of grid panel units are calculated;

[0012] Step 300, calculating the axial force, bending moment, shear force and cross-sectional normal stress of the vertical rod of any layer of grid panel unit based on the static equilibrium condition;

[0013] Step 400 , based on the static equilibrium condition, calculate the axial force, bending moment, shear force and cross-sectional normal stress of the horizontal bars of any layer of grid panel units.

[0014] The force calculation method for the reinforced mesh panel reinforced earth retaining wall of the present invention is based on the static equilibrium conditions of the mesh panel units of the reinforced mesh panel structure and the local soil wedges involved in the units, fully reflecting the interaction between the reinforced mesh panel structure and the fill, and can simply and quickly calculate the internal forces of each component (such as oblique tie rods, vertical rods, horizontal rods and horizontal tie rods in corresponding layers) in the reinforced mesh panel reinforced earth retaining wall. The calculation content is comprehensive, the principle is reasonable, the concept is clear, the algorithm is simple, and it is convenient for actual and fast operation, overcoming the defects of traditional methods. There is no need for time-consuming, labor-intensive, and costly experiments or numerical simulation calculations, which can greatly improve the design calculation efficiency, and provide a fast and effective technical means and algorithm basis for the actual engineering design calculation operation of the reinforced mesh panel reinforced earth retaining wall, which has important technical significance and engineering application value.

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings that constitute part of this invention are intended to assist in understanding the invention. The contents provided in the drawings and their related descriptions in the present invention may be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 This is a structural diagram of a reinforced earth retaining wall with steel mesh panels.

[0018] Figure 2 Schematic diagram of the stress analysis model of any layer of mesh panel unit.

[0019] Figure 3 Schematic diagram of the load analysis model for the local soil wedge associated with any layer of mesh panel elements. DETAILED DESCRIPTION

[0020] The present invention is described clearly and completely below with reference to the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be noted that:

[0021] The technical solutions and technical features provided in each part of the present invention, including the following description, may be combined with each other unless there is any conflict.

[0022] In addition, the embodiments of the present invention described below are generally only part of the embodiments of the present invention, rather than all of the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts should fall within the scope of protection of the present invention.

[0023] Regarding the terms and units in the present invention: The terms "include", "have" and any variations thereof in the description and claims of the present invention and the related parts are intended to cover non-exclusive inclusions.

[0024] The specific implementation of the force calculation method of the steel grid panel reinforced earth retaining wall of the present invention includes the following steps:

[0025] Step 100: number the grid panel units from top to bottom, and calculate the lateral earth pressure and reinforcement tension acting on any layer of grid panel units based on the static equilibrium condition of the local soil wedge;

[0026] Step 200 , regarding the grid panel unit structure as a primary statically indeterminate structure, the axial force and cross-sectional normal stress of the oblique tie rods of any layer of grid panel units are calculated;

[0027] Step 300, calculating the axial force, bending moment, shear force and cross-sectional normal stress of the vertical rod of any layer of grid panel unit based on the static equilibrium condition;

[0028] Step 400 , based on the static equilibrium condition, calculate the axial force, bending moment, shear force and cross-sectional normal stress of the horizontal bars of any layer of grid panel units.

[0029] The following is a detailed description of each step.

[0030] Step 100

[0031] Figure 1 The diagram below is a structural diagram of a reinforced earth retaining wall with reinforced mesh panels. Figure 1 The steel mesh panel reinforced earth retaining wall shown is composed of fill 10, horizontally arranged reinforcement bars 60, and a steel mesh panel structure, wherein the steel mesh panel structure is composed of several layers of mesh panel units 20 stacked in sequence from top to bottom, and each layer of mesh panel unit 20 includes several oblique tie rods 30, vertical rods 40 and horizontal rods 50 and connecting rods therebetween. The reinforcement bars 60 are connected and fixed to the steel mesh panel structure at each horizontal rod 50; each vertical rod 40 and horizontal rod 50 is the same steel bar, and the bending angle of the steel bar is 90° or close to 90°; the reinforcement bars 60 are generally made of geosynthetics.

[0032] Figure 2 is a schematic diagram of the force analysis model of any layer of grid panel unit. Figure 2 As shown, for Figure 2 The rod system OAB (AB represents the diagonal rod, AO represents the vertical rod and BO represents the horizontal rod) of the i-th layer grid panel unit structure from top to bottom is subjected to the following forces: i , lateral earth pressure E acting on the vertical rod i , the upper vertical pressure P acting on the top of the horizontal rod i and the lower vertical reaction force N acting on the bottom of the horizontal rod i .

[0033] According to the static equilibrium condition, we can get:

[0034] T i +R L i -R U i =E i cosδ(1)

[0035] P i +E i sinδ=N i (2)

[0036]

[0037] Where i is the unit layer number of the mesh panel from top to bottom, i = 1, 2, 3…n, n is the total number of unit layers in the reinforced mesh panel structure; R i U 、R i L are the horizontal frictional resistances of the upper and lower surfaces of the horizontal bars in the i-th grid panel unit; δ is the external friction angle between the vertical bars and the fill; a and b are the lengths of the vertical bars and horizontal bars in the i-th grid panel unit structure, respectively; x i N i The horizontal distance between the action point and the bottom end of the vertical rod; ξ i For E i The ratio of the height of the point of action from the bottom end of the vertical rod to a.

[0038] ξ i The calculation expression is:

[0039]

[0040] Figure 3 Schematic diagram of the load analysis model of the local soil wedge associated with any layer of mesh panel elements. Figure 3 The local soil wedge (denoted by OADB) associated with the top-down i-th grid panel unit shown in FIG. 1 can be obtained from the vertical and horizontal static equilibrium conditions respectively:

[0041]

[0042] Where W i is the weight of the soil within the height range of the i-th grid panel unit, W i =γab, γ is the fill weight; is the internal friction angle of fill; for N i , N0=q w b,q w is the static area distribution load acting on the top surface of the wall, which is generally taken as zero; E i s is the lateral earth pressure acting on the BD surface on the rear side of the local soil wedge.

[0043] According to the classical earth pressure theory, E i s The calculation expression is:

[0044]

[0045] Where k is the lateral earth pressure coefficient, and its value is between the static earth pressure coefficient Active earth pressure coefficient Between, generally can be taken as π is the ratio of the circumference of a circle to its circumference; h is the ratio of the circumference i h is the depth from the bottom of the horizontal bar of the i-th grid panel unit to the top surface of the fill, i =ai+h0, h0 is the equivalent soil column height of the top surface load of the fill behind the wall, h0=q / γ, q is the static area distributed load acting on the top surface of the fill.

[0046] According to Coulomb friction theorem, R i U 、R i L The calculation expression is:

[0047]

[0048] Where f is the friction coefficient between the horizontal rod and the fill. According to the Technical Specification for Application of Geosynthetics (GBT50290-2014), its value can be approximately (0.67 to 0.8) Generally, 0.75 is acceptable.

[0049] Combining equations (5), (6) and (8) we can get:

[0050]

[0051] Combining equations (1) to (9), we can get:

[0052] Ti =E i (cosδ-fsinδ)(10)

[0053]

[0054] P i =N i -E i sinδ(12)

[0055]

[0056] Therefore, substituting Equation (7) into Equation (9) can calculate the lateral earth pressure E acting on the vertical rod in the i-th layer grid panel unit: i , and then the lateral earth pressure E i Substituting into formula (10) the corresponding upper vertical pressure P can be calculated i , lower vertical reaction force N i and tensile strength T i .

[0057] For the case where the vertical rod in the grid panel unit is inclined, that is, the angle between it and the horizontal rod is less than 90°, and the angle between the vertical rod and the vertical is β, the actual β value is generally small. In this case, the above basic method can still be used for derivation. Simply replace δ in the above expression with δ-β to obtain the approximate calculation result in this case.

[0058] Step 200

[0059] Depend on Figure 2 The force analysis model shown in the figure shows that the grid panel unit is a statically indeterminate structure. Therefore, the force method in structural mechanics can be used to analyze its internal forces, and the axial force F of the oblique tie rod in the i-th grid panel unit can be obtained. i The calculation expression is:

[0060]

[0061] Δ 1P =Y1+Y2+Y3(16)

[0062]

[0063] Where E is the elastic modulus of the steel bars in the mesh panel unit; EA is the axial compressive or tensile stiffness of the diagonal tie rod in the i-th layer of mesh panel unit; I is the cross-sectional inertia moment of the vertical and horizontal bars in the i-th layer of mesh panel unit, and EI is its corresponding bending stiffness; δ 11 It's F i is the relative displacement between the two ends of the diagonal tie rod in the grid panel element (i.e., between points A and B on the rod system OAB) caused by the unit force; Δ1P It is the relative displacement between the two ends of the diagonal tie rod (i.e., between points A and B in the rod system OAB) caused by the external load on the grid panel unit. Y1, Y2, and Y3 are intermediate variables for calculation. The axial force is the tension that causes axial stretching of the diagonal tie rod.

[0064] Therefore, according to the material mechanics stress analysis method, the cross-sectional normal stress σ of the oblique tie rod in the i-th layer grid panel unit can be obtained: i AB The calculation expression is:

[0065]

[0066] Where S2 is the arrangement spacing of the oblique tie rods AB in the i-th layer of mesh panel unit; d2 is the diameter of the oblique tie rods AB in the i-th layer of mesh panel unit.

[0067] Steps 300-400

[0068] For the vertical rod in the i-th layer grid panel unit, the shear force Q of the vertical rod can be obtained from the static equilibrium condition: OA , axial force N OA and bending moment M OA The calculation expressions are:

[0069]

[0070]

[0071] Where, the axial force is the tensile force that causes axial stretching of the vertical rod, the shear force is the clockwise rotation around the vertical rod isolator, and the bending moment is the clockwise rotation; y is the height from point O at the bottom end of the vertical rod.

[0072] For the horizontal bar in the i-th layer grid panel unit, the shear force Q of the horizontal bar can be obtained from the static equilibrium condition: OB , axial force N OB , bending moment M OB The expressions are:

[0073]

[0074] Where x is the horizontal distance from point O, the bottom end of the vertical rod; the axial force is the tensile force that causes axial stretching of the horizontal rod, the shear force is the clockwise rotation around the horizontal rod isolator, and the bending moment is the clockwise rotation.

[0075] For the case where the vertical rod in the grid panel unit is inclined, that is, the angle between it and the horizontal rod is less than 90°, the internal force of each rod in the grid panel unit can still be derived and calculated according to the above basic method. The result can be expressed by multiplying the relevant result when the vertical rod is completely along the vertical direction by an increase coefficient greater than 1. This increase coefficient is related to the angle β of the vertical rod to the vertical direction. When β = 5°, 10°, and 15°, the increase coefficients of the internal force of the vertical rod are 1.043, 1.083, and 1.122, respectively.

[0076] Therefore, according to the material mechanics stress analysis method, the cross-sectional normal stress σ of the vertical rod in the i-th layer grid panel unit can be obtained: i OA and the cross-sectional normal stress σ of the horizontal rod i OB The calculation expressions are:

[0077]

[0078]

[0079] Where S1 is the spacing of the vertical rods in the i-th grid panel unit; d1 is the diameter of the vertical rods in the i-th grid panel unit.

[0080] It can be seen from equations (21) to (28) that the maximum values ​​of the shear force, axial force, bending moment and cross-sectional normal stress of the vertical and horizontal bars in each layer of grid panel units are all located at the intersection point O of the vertical and horizontal bars, that is, y = 0 and x = 0. Therefore, the shear force, axial force, bending moment and cross-sectional normal stress values ​​of the vertical and horizontal bars at point O can be used as the representative values ​​of their shear force, axial force, bending moment and cross-sectional normal stress.

[0081] The beneficial effects of the present invention are described below through specific examples.

[0082] The calculation object of this embodiment is a fill earthwork project supported by a reinforced earth retaining wall with reinforced mesh panels. The mesh panels are reinforced with the same type of steel bars. The friction coefficient between the horizontal bars of the mesh panel units and the fill earth is taken as Take the lateral earth pressure coefficient The other relevant calculation parameters are shown in Table 1.

[0083] Table 1

[0084]

[0085] Substituting the relevant parameters into equations (7) and (9), we can obtain:

[0086]

[0087] Then E iSubstituting into formula (10), we can get:

[0088]

[0089] At the same time, according to formulas (11) to (13) and formula (4), N can be calculated i 、P i and x i .

[0090] Specifically, the lateral earth pressure E on the i-th layer reinforced mesh panel element can be obtained as i , stretching force T i , lower vertical reaction force N i , upper vertical pressure P i and the lower vertical reaction force N i The horizontal distance x from the point of action to the bottom of the vertical rod i The results are shown in Table 2. Then, the cross-sectional normal stress σ of the oblique tie rod can be calculated by equations (14) and (20): i AB , the specific results are shown in Table 2.

[0091] Table 2

[0092] i <![CDATA[E i (kN / m)]]> <![CDATA[N i (kN / m)]]> <![CDATA[P i (kN / m)]]> <![CDATA[x i (m)]]> <![CDATA[T i (kN / m)]]> <![CDATA[σ i AB (MPa)]]> 1 1.636 7.813 7.528 0.193 1.488 11.255 2 3.243 16.750 16.187 0.196 2.950 21.629 3 4.850 26.813 25.970 0.199 4.411 32.223 4 6.456 38.000 36.879 0.202 5.873 42.964 5 8.063 50.313 48.912 0.205 7.334 53.813 6 9.670 63.750 62.071 0.207 8.796 64.749 7 11.276 78.313 76.354 0.209 10.257 75.753 8 12.883 94.000 91.763 0.211 11.718 86.814 9 14.489 110.813 108.296 0.213 13.180 97.923 10 16.096 128.750 125.955 0.214 14.641 109.072 11 17.703 147.813 144.738 0.216 16.103 120.256 12 19.309 168.000 164.647 0.217 17.564 131.470 13 20.916 189.313 185.680 0.218 19.025 142.711 14 22.523 211.75 207.839 0.219 20.487 153.974 15 24.129 235.313 231.1225 0.221 21.948 165.258 16 25.736 260.000 255.531 0.222 23.410 176.560 17 27.342 285.813 281.065 0.223 24.871 187.877 18 28.949 312.750 307.723 0.223 26.333 199.209 19 30.556 340.813 335.507 0.224 27.794 210.554 20 32.162 370.000 364.415 0.225 29.255 221.910 21 33.769 400.313 394.449 0.226 30.717 233.277 22 35.376 431.750 425.607 0.226 32.178 244.653 23 36.982 464.313 457.891 0.227 33.640 256.039 24 38.589 498.000 491.299 0.228 35.101 267.432

[0093] Substituting the relevant parameters into equations (21), (22), (23), (27) and (24), (25), (26), (28), we can obtain the shear force, axial force, bending moment and cross-sectional normal stress of the vertical and horizontal bars in the i-th layer grid panel unit. The maximum values ​​of these internal forces of the vertical and horizontal bars of each layer grid panel unit are all located at the intersection point O of the vertical and horizontal bars, that is, y = 0 and x = 0. Therefore, the shear force, axial force, bending moment and maximum cross-sectional normal stress values ​​of the vertical and horizontal bars at point O are taken as the representative values ​​of their internal forces. The specific calculation results are shown in Table 3.

[0094] Table 3

[0095]

[0096] For the embodiment, the comparison of the maximum normal stress values ​​of the cross section of the vertical rods and horizontal rods at point O in each layer of the grid panel unit obtained by the FLAC3D numerical simulation method and the results of the present invention is shown in Table 4.

[0097] Table 4

[0098]

[0099] It can be seen that the calculation results of the method of the present invention are relatively consistent with those of the numerical simulation method. The maximum absolute value of the relative deviation between the two (the results of the present invention relative to the numerical simulation results) is only 13.92%, which is acceptable in actual engineering, indicating that the method of the present invention has certain rationality.

[0100] The above describes the relevant contents of the present invention. Based on this description, a person skilled in the art will be able to implement the present invention. Based on the above contents of the present invention, all other embodiments obtained by a person skilled in the art without making any creative efforts should fall within the scope of protection of the present invention.

Claims

1. Method for calculating the load bearing of reinforced earth retaining wall with steel grid panel. The reinforced earth retaining wall with steel grid panel consists of backfill, horizontally arranged reinforcement and steel grid panel structure. The steel mesh panel structure is composed of several layers of mesh panel units stacked sequentially from top to bottom. Each layer of mesh panel unit contains several diagonal tie bars, vertical bars, horizontal bars, and connecting bars therebetween. The tie bars are connected and fixed to the steel mesh panel structure at each horizontal bar. The calculation method includes the following steps: Step 100: number the grid panel units from top to bottom, and calculate the lateral earth pressure and reinforcement tension acting on any layer of grid panel units based on the static equilibrium condition of the local soil wedge; Step 200 , regarding the grid panel unit structure as a primary statically indeterminate structure, the axial force and cross-sectional normal stress of the oblique tie rods of any layer of grid panel units are calculated; Step 300, calculating the axial force, bending moment, shear force and cross-sectional normal stress of the vertical rod of any layer of grid panel unit based on the static equilibrium condition; Step 400 , based on the static equilibrium condition, calculate the axial force, bending moment, shear force and cross-sectional normal stress of the horizontal bars of any layer of grid panel units.

2. The method for calculating the stress of a reinforced earth retaining wall with a steel grid panel according to claim 1, wherein: In step 100, the calculation expressions of the earth pressure and reinforcement tension acting on any layer of grid panel elements are: P i =N i -E i sinδ; T i =E i (cosδ-fsinδ); Where i is the mesh panel unit layer number from top to bottom, i = 1, 2, 3…n, n is the total number of mesh panel unit layers in the reinforced mesh panel structure; E i is the lateral earth pressure acting on the vertical rod in the grid panel unit of the i-th layer; N i is the lower vertical reaction force at the bottom of the horizontal bar of the i-th layer grid panel unit; P i is the upper vertical pressure acting on the top of the horizontal rod of the grid panel unit in the i-th layer; T i is the tension of the reinforcement of the mesh panel unit in the i-th layer; E i s is the lateral earth pressure acting on the rear side of the local soil wedge associated with the grid panel element at the i-th layer; is the internal friction angle of fill; W i is the deadweight of the soil within the height range of the i-th grid panel unit; f is the friction coefficient between the horizontal rod and the fill; δ is the external friction angle between the vertical rod and the fill.

3. The method for calculating the stress of a reinforced earth retaining wall with a steel grid panel as claimed in claim 2, wherein: E i s The calculation expression is: h i The calculation expression is: h i =ai+h0; Where k is the lateral earth pressure coefficient; γ is the fill weight; h i is the depth from the bottom of the horizontal rod of the i-th layer grid panel unit to the top surface of the fill; a is the length of the vertical rod in the i-th layer grid panel unit; h0 is the equivalent soil column height of the load on the top surface of the fill behind the wall, h0 = q / γ, q is the static area distributed load acting on the top surface of the fill.

4. The method for calculating the stress of a reinforced earth retaining wall with a steel grid panel as claimed in claim 3, wherein: The calculation expressions for the axial force and cross-sectional normal stress of the oblique tie rod of any layer of grid panel unit in step 200 are: Δ 1P =Y1+Y2+Y3; Where, F i is the axial force of the diagonal tie rod; σ i AB is the cross-sectional normal stress of the oblique tie rod; b is the length of the horizontal rod in the i-th layer of mesh panel unit; E is the elastic modulus of the steel bar in the mesh panel unit; I is the cross-sectional inertia moment of the vertical and horizontal rods in the i-th layer of mesh panel unit, and EI is its corresponding bending stiffness; EA is the axial compressive stiffness or tensile stiffness of the oblique tie rod in the i-th layer of mesh panel unit; x i N i The horizontal distance between the action point and the bottom end of the vertical rod; ξ i For E i The ratio of the height of the action point to the bottom of the vertical rod to a; S2 is the arrangement spacing of the oblique rods in the i-th layer of grid panel unit; d2 is the diameter of the oblique rods in the i-th layer of grid panel unit; π is pi; δ 11 It's F i The relative displacement between the two ends of the diagonal tie rod in the grid panel unit caused by unit force; Δ 1P It is the relative displacement between the two ends of the diagonal tie rod caused by the external load on the grid panel unit. Y1, Y2, and Y3 are intermediate variables for calculation.

5. The method for calculating the stress of a reinforced earth retaining wall with a steel grid panel according to claim 4, characterized in that: ξ i The calculation expression is: x i The calculation expression is:

6. The method for calculating the stress of a reinforced earth retaining wall with a steel grid panel according to claim 4, wherein: The calculation expressions of the axial force, bending moment, shear force and cross-sectional normal stress of the vertical rod of any layer of grid panel unit are: Where Q OA is the shear force of the vertical rod; N OA is the axial force of the vertical rod; M OA is the bending moment of the vertical rod; σ i OA is the normal stress of the vertical rod cross section; y is the height from the bottom end of the vertical rod; S1 is the arrangement spacing of the vertical rods in the i-th layer grid panel unit.

7. The method for calculating the stress of a reinforced earth retaining wall with a steel grid panel according to claim 4, wherein: The calculation expressions for the axial force, bending moment, shear force and cross-sectional normal stress of the horizontal bar of any layer of mesh panel unit are: Where R i U 、R i L are the horizontal frictional resistances on the upper and lower surfaces of the horizontal rods in the i-th grid panel unit; Q OB is the shear force of the horizontal rod; N OB is the axial force of the horizontal rod; M OB is the bending moment of the horizontal rod; σ i OB is the normal stress in the cross section of the horizontal rod; x is the horizontal distance from the bottom end of the vertical rod.

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