Method for correcting default value of soil pressure behind gabion retaining wall

Abstract

The invention relates to the technical field of intelligent monitoring devices, in particular to a gabion retaining wall back soil pressure default value correction method which comprises the steps that according to the construction sequence, soil pressure boxes are sequentially buried behind a wall from low to high, and monitoring data are recorded; according to the residual pressure data of the soil pressure box, drawing a wall back soil pressure default value fitting line and a same-project analogy line by adopting a least square method; based on gabion retaining wall design parameters and behind-wall backfill mechanical parameters, a horizontal stratification method is adopted to calculate a behind-wall soil pressure theoretical line; and calculating the cross cumulative density of a circle with the radius of r on the contour line of the soil pressure default value, the default value fitting line, the same-project analogy line and the theoretical line, and taking the soil pressure value corresponding to the maximum cross cumulative density as the optimal correction value of the behind-wall soil pressure default value. The construction requirements of the green reinforced retaining wall under complex conditions can be met, the problem of data missing caused by instrument damage or transmission line damage is effectively solved, and intelligent monitoring of the reinforced gabion retaining wall is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of intelligent monitoring, and in particular to a method for correcting a default value of soil pressure behind a gabion retaining wall. Background Art

[0002] In recent years, the pace of infrastructure construction in my country has been changing with each passing day. In particular, green gabion retaining walls, which are made of geogrids and polyhedral gabion nets wrapped with gravel and have certain flexibility and deformation adaptability, are widely used in engineering. Geopolymers are laid inside the gabion retaining wall as reinforcement, so that this artificial composite soil can withstand tension, compression and shear. As the engineering geological conditions encountered become increasingly complex, the design requirements for gabion retaining walls have become higher. The soil pressure behind the wall is an important load for the design of the retaining wall structure section and the stability verification. Its size and distribution law are closely related to the bearing mode and displacement mode of the retaining wall. Therefore, once the construction methods and engineering measures are improper, it will be very easy to cause engineering disasters such as retaining wall instability and slope collapse, which will cause extremely heavy casualties and economic losses.

[0003] At present, there are not many studies on the soil pressure behind gabion retaining walls, and the research methods are mainly theoretical research, numerical simulation, and model tests. Theoretical research is often based on multiple assumptions, and numerical simulation has a certain degree of empiricism in the selection of the constitutive relationship between the retaining wall and the soil. The similarity relationship of the model test is generally difficult to meet. The calculation results mentioned above are somewhat different from the actual engineering, and cannot meet the guidance needs of gabion retaining wall construction.

[0004] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a method for correcting the default value of the soil pressure behind a gabion retaining wall, which effectively solves the problem of data loss caused by instrument damage or transmission line damage and realizes intelligent monitoring of reinforced gabion retaining walls.

[0006] To achieve the above object, the present invention provides a method for correcting the default value of the soil pressure behind a gabion retaining wall, comprising the following steps: Step S1: at least two monitoring sections are evenly spaced behind the reinforced gabion retaining wall and along the extension direction of the retaining wall. In each monitoring section, multiple earth pressure boxes are buried in order from low to high according to the construction sequence of the reinforced gabion retaining wall, and the monitoring data of each earth pressure box is recorded; Step S2: Based on the monitoring data of the remaining earth pressure box, the default value fitting line of the earth pressure behind the wall and the analogy line of the same project are drawn by using the least square method; Step S3: Based on the design parameters of the reinforced gabion retaining wall and the mechanical parameters of the fill of the gabion retaining wall structure behind the wall, the theoretical line of the soil pressure behind the wall is calculated by using the horizontal layering method; Step S4: Calculate the intersection cumulative density of the circle with a radius of r on the contour line of the default value of earth pressure, the fitting line of the default value of earth pressure, the analogy line of the same project and the theoretical line of earth pressure, and take the earth pressure value corresponding to the maximum density value as the optimal correction value of the default value of the earth pressure behind the reinforced gabion retaining wall.

[0007] Furthermore, the reinforced gabion retaining wall is a gabion face wall formed by stacking multiple gabion cages filled with crushed stone. The multiple gabion cages are fixedly connected in sequence from bottom to top, a high-tenacity polyester yarn cluster grid is arranged between two adjacent gabion cages above and below, and a retaining wall elevation adjustment concrete block is arranged on the top of each level of gabion cages.

[0008] Furthermore, a plurality of the earth pressure boxes are arranged behind the reinforced gabion retaining wall by means of a hanging bag method, and the plurality of the earth pressure boxes are respectively connected to a comprehensive data collector and are centrally powered by the comprehensive data collector.

[0009] Furthermore, each of the monitoring sections is a vertical plane perpendicular to the reinforced gabion retaining wall at its location, and the heights of the multiple earth pressure boxes in the at least two monitoring sections are set in one-to-one correspondence; and the monitoring data on one of the monitoring sections is defined as the same engineering analog data.

[0010] Furthermore, in step S2: the bottom of the gabion retaining wall on the same monitoring section is taken as the coordinate origin, the measured pressure value of the earth pressure box is the x value, and the buried height corresponding to the earth pressure box is the y value, and a coordinate system and a data point set (x, y) are constructed; assuming that the number of earth pressure boxes buried on the same monitoring section is n , the remaining number is m ,but m ≤ n ; The least squares method is expressed as ,in is the residual function, which can be a linear function or a nonlinear function. i= 1,2, …m ; w i is the optimal parameter to be determined, x i For the i The measured pressure value of each soil pressure cell; y i For the i The burial height of the earth pressure box.

[0011] Furthermore, in step S3, the wall of the reinforced gabion retaining wall has three types of displacement modes: translation, rotation around the bottom of the wall, and rotation around the top of the wall. Taking into account the soil arch effect and the shear stress between soil layers, the horizontal layering method is used to construct the equilibrium equation of the micro-unit, and the theoretical line of the soil pressure behind the wall under any displacement mode is obtained by cumulative summation.

[0012] Furthermore, in step S4, a circular equation of the proximity r of the default value point is constructed on one or more default earth pressure contour lines, and the intersection length with the default value fitting line, the same engineering analogy line and the theoretical line is defined as the intersection cumulative density; the earth pressure value corresponding to the center coordinate value corresponding to the maximum cross cumulative density is the optimal correction value of the measured default value of the earth pressure behind the gabion retaining wall.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a method for correcting the default value of soil pressure behind a gabion retaining wall, comprising: burying a plurality of soil pressure boxes in order from low to high in the monitoring section behind the reinforced gabion retaining wall according to the construction sequence, and recording monitoring data; using the least square method to draw the default value fitting line of soil pressure behind the wall and the analogy line of the same project according to the remaining monitoring data of the soil pressure boxes; using the horizontal layering method to calculate the theoretical line of soil pressure behind the wall based on the design parameters of the gabion retaining wall and the mechanical parameters of the backfill soil behind the wall; calculating the cross-cumulative density of the circle with a radius of r on the default value contour line, the default value fitting line, the analogy line of the same project and the theoretical line, and taking the soil pressure value corresponding to the maximum cross-cumulative density as the best correction value of the default value of soil pressure behind the gabion retaining wall. The invention can meet the construction requirements of green reinforced retaining walls under complex conditions, capture the soil pressure state behind the wall in real time, informatize the variation law of important external loads of the wall, optimize the construction and design schemes, and realize the safety early warning of the gabion retaining wall.

[0014] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 It is a flowchart of a method for correcting a default value of soil pressure behind a gabion retaining wall according to an embodiment of the present invention; Figure 2 Schematic diagram of the placement of the earth pressure box behind the gabion retaining wall according to an embodiment of the present invention; Figure 3 2 is a schematic diagram of the default value analysis of the soil pressure behind the gabion retaining wall according to an embodiment of the present invention; Figure 4 is a probability density distribution diagram of the modified value of the earth pressure behind the gabion retaining wall according to an embodiment of the present invention; Among them, 1-reinforced gabion retaining wall; 2-earth pressure box; 3-high-tenacity polyester yarn cluster grid; 4-retaining wall elevation adjustment concrete block; 5-gabion retaining wall structure fill. DETAILED DESCRIPTION

[0016] The present invention will be described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0017] See also Figure 1 This embodiment provides a method for correcting the default value of the soil pressure behind a gabion retaining wall, comprising the following steps: S1: At least two monitoring sections are evenly spaced behind the reinforced gabion retaining wall 1 and along the extension direction of the retaining wall. Each monitoring section is a vertical plane perpendicular to the reinforced gabion retaining wall 1 at its location. On each monitoring section, multiple earth pressure boxes 2 are buried in order from low to high according to the construction sequence of the reinforced gabion retaining wall 1, and the monitoring data of each earth pressure box 2 is recorded. Among them, the distance between two adjacent monitoring sections is 3~10m; the heights of multiple earth pressure boxes 2 in two adjacent monitoring sections are set one by one.

[0018] The reinforced gabion retaining wall 1 is a gabion face wall formed by stacking multiple gabion cages filled with gravel, and the gabion cages are box-shaped polygonal metal cage meshes. Multiple gabion cages are fixedly connected in sequence from bottom to top, and a high-toughness polyester yarn cluster grid 3 is arranged between the upper and lower adjacent gabion cages, and a retaining wall elevation adjustment concrete block 4 is arranged on the top of each level of gabion cage. Multiple earth pressure boxes 2 are arranged between the reinforced gabion retaining wall 1 and the gabion retaining wall structure fill 5 by the hanging bag method, and the multiple earth pressure boxes 2 are respectively connected to the comprehensive data collector and are centrally powered by the power supply in the comprehensive data collector. The monitoring data on one of the monitoring sections is defined as the same engineering analog data.

[0019] S2: Since some earth pressure boxes 2 may be damaged during the construction process, the pressure boxes with normal functions are called the remaining earth pressure boxes; the damage rate of earth pressure boxes 2 does not exceed 30%. According to the monitoring data of the remaining earth pressure boxes 2, the least squares method is used to draw the default value fitting line of the earth pressure behind the wall and the analogy line of the same project. Specifically, the bottom of the gabion retaining wall of the same monitoring section is taken as the coordinate origin, the measured pressure value of the earth pressure box 2 is the x value, and the corresponding buried height of the earth pressure box 2 is the y value. The coordinate system and data point set (x, y) are constructed; it is assumed that the number of earth pressure boxes 2 buried on the same monitoring section is n, the remaining number is m ,like m < n , it indicates that the pressure box is damaged; if m = n , it indicates that there is no pressure cell damage. The expression of the least square method used in this step is ,in is the residual function, which can be a linear function or a nonlinear function. i =1,2,… m ; w i is the optimal parameter to be determined; x i For the i The measured pressure value of each soil pressure cell; y i For the i The burial height of the earth pressure box.

[0020] S3: Based on the design parameters of the reinforced gabion retaining wall 1 and the mechanical parameters of the gabion retaining wall structure fill 5, the theoretical line of the soil pressure behind the wall is calculated using the horizontal layering method. Since the reinforced gabion retaining wall 1 has three types of displacement modes, namely translation (T mode), rotation around the bottom of the wall (RB mode) and rotation around the top of the wall (RT mode), the soil arch effect and the shear stress between soil layers are comprehensively considered. In this step, the horizontal layering method is used to construct the equilibrium equation of the small unit, and the cumulative sum can be used to obtain the theoretical line of the soil pressure behind the wall under any displacement mode.

[0021] S4: Calculate the intersection cumulative density of the circle with radius r on the default value contour line of soil pressure, the default value fitting line of soil pressure, the analogy line of the same project and the theoretical line of soil pressure, and take the soil pressure value corresponding to the maximum intersection cumulative density as the best correction value of the default value of soil pressure behind the reinforced gabion retaining wall 1. Specifically, construct a circular equation of the proximity r of the default value point of soil pressure on one or more default value contour lines of soil pressure, and define the intersection length of the circular equation with the default value fitting line, the analogy line of the same project and the theoretical line as the intersection cumulative density; the soil pressure value corresponding to the coordinate value of the center of the circle corresponding to the maximum intersection cumulative density is the best correction value of the measured default value of soil pressure behind the gabion retaining wall.

[0022] Example

[0023] Take a reinforced gabion retaining wall project in Yueyang as an example. Figure 2As shown, the reinforced gabion retaining wall 1 is a galvanized gabion retaining wall with a high wear-resistant organic coating. It is divided into three levels. The design height of each level from bottom to top is 7m, 10m, and 10m respectively. The lengths of the high-tenacity polyester yarn cluster grid 3 are 20m, 18m, and 12m respectively. The gabion design slope is 1:0.2, and the width of each platform is 2m. The large (length, height, and width) size of the gabion cage is 3m×1m×1m, and the small (length, height, and width) size is 3m×0.5m×0.8m. The backfill 5 of the gabion retaining wall structure behind the wall is miscellaneous fill, with an elastic modulus of 4.5Mpa and a comprehensive density of 18.5kg / m 3 , the internal friction angle is 12°, and the cohesion is 9.7 kPa. The retaining wall elevation adjustment concrete block 4 is a concrete block with a compressive strength grade of C30, which is made by mixing ordinary silicate cement with sand and crushed stone.

[0024] The earth pressure cell 2 used in the reinforced gabion retaining wall 1 is a JMZX-5020Am vibrating wire pressure cell, with a comprehensive range of 2MPa, a sensitivity of 0.001MPa, a vertical height interval of 2m, a horizontal interval of 6m, and 14 earth pressure cells arranged in each monitoring section. The instrument was damaged at a buried depth of 12m, and the measured earth pressure data behind the wall of the default value data group and the engineering analogy group are as follows:

[0025] like Figure 3 As shown in the figure, using the least squares method, the fitting curve equation of the default value group of earth pressure is calculated as: , fitting correlation coefficient , engineering analogy curve equation , fitting correlation coefficient .

[0026] Reinforced gabion retaining wall is a flexible retaining wall. In actual engineering, there are flexible deformation characteristics, which are generally manifested as rotation around the bottom of the wall. According to Rankine's earth pressure theory, the theoretical curve is obtained by using the horizontal layer method: .

[0027] like Figure 4 As shown, the influence range of the point set in this embodiment is a circle with the default value point as the center and a radius of r. The longer the intersection length of the circle with the default value fitting line, the same engineering analogy line and the theoretical line, the closer the adjacent relationship between the point position and the three. At this time, R is defined as 1, then: The cross cumulative density equation is .

[0028] Through numerical calculation, the maximum cross-cumulative density is 5.928, and the optimal correction value of the default value of the soil pressure behind the gabion retaining wall is 127.826 kPa.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for correcting the default value of soil pressure behind a gabion retaining wall, characterized in that: include: Step S1: at least two monitoring sections are evenly spaced behind the reinforced gabion retaining wall (1) and along the extension direction of the retaining wall. In each monitoring section, a plurality of earth pressure boxes (2) are buried in order from low to high according to the construction sequence of the reinforced gabion retaining wall (1), and the monitoring data of each earth pressure box (2) is recorded; Step S2: Based on the remaining monitoring data of the earth pressure box (2), a fitting line of the default value of the earth pressure behind the wall and an analogy line of the same project are drawn using the least square method; Step S3: Based on the design parameters of the reinforced gabion retaining wall (1) and the mechanical parameters of the backfill (5) of the gabion retaining wall structure behind the wall, a theoretical line of soil pressure behind the wall is calculated by using a horizontal layering method; Step S4: Calculate the cross-cumulative density of a circle with a radius of r on the contour line of the default value of earth pressure, the default value fitting line of earth pressure, the analogy line of the same project and the theoretical line of earth pressure, and take the earth pressure value corresponding to the maximum cross-cumulative density as the optimal correction value of the default value of earth pressure behind the reinforced gabion retaining wall (1).

2. The method according to claim 1, characterized in that: The reinforced gabion retaining wall (1) is a gabion face wall formed by stacking a plurality of gabion cages filled with crushed stones, wherein the plurality of gabion cages are fixedly connected in sequence from bottom to top, a high-tenacity polyester yarn clustering grid (3) is arranged between two adjacent gabion cages, and a retaining wall elevation adjustment concrete block (4) is arranged on the top of each level of gabion cages.

3. The method according to claim 1, characterized in that The plurality of earth pressure boxes (2) are arranged behind the reinforced gabion retaining wall (1) by means of a hanging bag method, and the plurality of earth pressure boxes (2) are respectively connected to a comprehensive data collector and are centrally powered by the comprehensive data collector.

4. The method according to claim 1, characterized in that: Each monitoring section is a vertical plane perpendicular to the reinforced gabion retaining wall (1) at its location, and the heights of the plurality of earth pressure boxes (2) in the at least two monitoring sections are arranged in one-to-one correspondence; and the monitoring data on one of the monitoring sections is defined as the same engineering analogy data.

5. The method according to claim 1, characterized in that In step S2: the bottom of the gabion retaining wall on the same monitoring section is taken as the coordinate origin, the measured pressure value of the earth pressure box (2) is taken as the x value, and the corresponding buried height of the earth pressure box (2) is taken as the y value, and a coordinate system and a data point set (x, y) are constructed; assuming that the number of earth pressure boxes (2) buried on the same monitoring section is n , the remaining number is m ,but m ≤ n ; The least squares method is expressed as ,in is the residual function, i= 1,2, …m ; w i is the optimal parameter to be determined; x i For the i The measured pressure value of each soil pressure cell; y i For the i The burial height of the earth pressure box.

6. The method according to claim 1, characterized in that In step S3, the reinforced gabion retaining wall (1) has three types of displacement modes: translation, rotation around the wall bottom and rotation around the wall top; taking into account the soil arch effect and the shear stress between soil layers, the horizontal layer division method is used to construct the equilibrium equation of the micro-unit, and the theoretical line of the soil pressure behind the wall under any displacement mode is obtained by cumulative summation.

7. The method according to claim 1, characterized in that In step S4, a circular equation of the proximity r of the default value points is constructed on one or more default earth pressure contour lines, and the intersection length of the circular equation with the default earth pressure fitting line, the same engineering analogy line and the earth pressure theoretical line is defined as the intersection cumulative density; the earth pressure value corresponding to the center coordinate value corresponding to the maximum cross cumulative density is the optimal correction value of the measured default earth pressure behind the gabion retaining wall.

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