A method for correcting the default value of earth pressure behind a gabion retaining wall

Abstract

The present invention relates to the technical field of intelligent monitoring devices, and particularly to a method for correcting the default value of earth pressure behind a gabion retaining wall. The method includes: burying earth pressure cells behind the wall from low to high in sequence according to the construction order and recording the monitoring data; using the least squares method to draw the fitting line of the default value of earth pressure behind the wall and the analog line of the same project based on the remaining earth pressure cell pressure data; calculating the theoretical line of earth pressure behind the wall by using the horizontal layer division method 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 a circle with a radius of r on the contour line of the default value of earth pressure with the fitting line of the default value, the analog line of the same project, and the theoretical line, and taking the earth pressure value corresponding to the maximum cross cumulative density as the best correction value of the default value of earth pressure behind the wall. The present invention can meet the construction requirements of green reinforced retaining walls under complex conditions, effectively solve the problem of data loss caused by instrument damage or transmission line damage, and realize the intelligent monitoring of reinforced gabion retaining walls.

Description

Technical Field

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

[0002] In recent years, the pace of infrastructure construction in China has been changing with each passing day. In particular, the green gabion retaining wall, which is composed of geogrid and multi-faceted gabion mesh wrapped with crushed stones and has certain flexibility and deformation adaptability, has been widely used in engineering. A geosynthetic is laid inside the gabion retaining wall for reinforcement, enabling this artificially composite soil mass to withstand tensile, compressive, and shear forces. As the encountered engineering geological conditions become increasingly complex, the design requirements for gabion retaining walls become higher. The earth pressure behind the wall is an important load for the design of the retaining wall structure section and the stability check. Its magnitude and distribution law are closely related to the bearing mode and displacement mode of the retaining wall. Therefore, once the construction method and engineering measures are inappropriate, engineering disasters such as retaining wall instability and slope collapse are likely to occur, resulting in extremely heavy casualties and economic losses.

[0003] At present, there is not much research on the earth pressure behind gabion retaining walls, and the research methods mainly include theoretical research, numerical simulation, and model tests. Among them, theoretical research is often based on various assumptions. There is a certain degree of empiricism in the selection of the constitutive relationship between the retaining wall and the soil mass in numerical simulation. It is generally difficult to meet the similarity relationship in model tests. The calculated results have a certain difference from the engineering practice and cannot meet the guiding requirements for the construction of gabion retaining wall projects.

[0004] The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present invention, and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art 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 earth pressure behind a gabion retaining wall, which effectively solves the problem of data loss caused by instrument damage or transmission line damage, and realizes the intelligent monitoring of the reinforced gabion retaining wall.

[0006] To achieve the above purpose, the present invention provides a method for correcting the default value of the earth pressure behind a gabion retaining wall, including the following steps:

[0007] Step S1: At least two monitoring sections are evenly spaced along the extension direction behind the reinforced gabion retaining wall. On each monitoring section, a plurality of earth pressure cells are buried in sequence from low to high according to the construction sequence of the reinforced gabion retaining wall, and the monitoring data of each earth pressure cell is recorded;

[0008] Step S2: According to the monitoring data of the remaining earth pressure cells, use the least squares method to draw the fitting line of the default value of the earth pressure behind the wall and the analogy line of the same project;

[0009] Step S3: Based on the design parameters of the reinforced gabion retaining wall and the mechanical parameters of the fill soil of the gabion retaining wall structure behind the wall, use the horizontal layer division method to calculate the theoretical line of the earth pressure behind the wall;

[0010] Step S4: Calculate the cross cumulative density of the circle with radius r on the contour line of the default value of the earth pressure, the fitting line of the default value of the earth pressure, the analogy line of the same project, and the theoretical line of the earth pressure. Take the earth pressure value corresponding to the maximum density value as the best correction value of the default value of the earth pressure behind the reinforced gabion retaining wall.

[0011] Furthermore, the reinforced gabion retaining wall is a gabion facing wall formed by stacking multiple gabion cages filled with gravel. The multiple gabion cages are fixedly connected in sequence from bottom to top. A high-tenacity polyester yarn bundle grille is arranged between two adjacent gabion cages up and down, and a retaining wall elevation adjustment concrete block is arranged at the top of each stage of gabion cage.

[0012] Furthermore, the multiple earth pressure cells are arranged behind the reinforced gabion retaining wall by the hanging bag method, and the multiple earth pressure cells are respectively connected to a comprehensive acquisition instrument and centrally powered by the comprehensive acquisition instrument.

[0013] Furthermore, each monitoring section is a vertical plane perpendicular to the reinforced gabion retaining wall at its location, and the heights of the multiple earth pressure cells 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 analogy data of the same project.

[0014] Furthermore, in Step S2: Taking the bottom of the gabion retaining wall on the same monitoring section as the coordinate origin, the measured pressure value of the earth pressure cell as the x value, and the corresponding buried height of the earth pressure cell as the y value, construct a coordinate system and a data point set (x, y); assuming that the number of earth pressure cells buried on the same monitoring section is n , the remaining number is m , then m ≤ n ; The least squares expression form is , where is the residual function, which can be a linear function or a non-linear function, i= 1, 2, …m ; w i is the optimal undetermined parameter, x i is the measured pressure value of the i th earth pressure cell; y i is thei The embedding height of a soil pressure cell.

[0015] Furthermore, in step S3, there are three types of displacement modes for the wall of the reinforced gabion retaining wall, namely translational displacement, rotation about the bottom of the wall, and rotation about the top of the wall. Considering the soil arch effect and the shear stress between soil layers comprehensively, the horizontal layer division method is used to construct the equilibrium equation of the micro-element, and the theoretical line of the earth pressure behind the wall under any displacement mode is obtained by cumulative summation.

[0016] Furthermore, in step S4, a circular equation of the proximity r of the default value points is constructed on one or more contour lines of the earth pressure default value. The intersection length with the default value fitting line, the same project analogy line, and the theoretical line is defined as the intersection cumulative density; the earth pressure value corresponding to the center coordinate value of the maximum intersection cumulative density is the best correction value of the measured default value of the earth pressure behind the gabion retaining wall.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] A method for correcting the default value of the earth pressure behind a gabion retaining wall of the present invention includes burying a plurality of soil pressure cells in sequence from low to high according to the construction sequence on the monitoring section behind the reinforced gabion retaining wall, and recording the monitoring data; according to the monitoring data of the remaining soil pressure cells, using the least squares method to draw the default value fitting line and the same project analogy line of the earth 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, using the horizontal layer division method to calculate the theoretical line of the earth pressure behind the wall; calculating the intersection cumulative density of the circle with a radius of r on the contour line of the default value with the default value fitting line, the same project analogy line, and the theoretical line, and taking the earth pressure value corresponding to the maximum intersection cumulative density as the best correction value of the default value of the earth pressure behind the gabion retaining wall. The present invention can meet the construction requirements of green reinforced retaining walls under complex conditions, capture the earth pressure state behind the wall in real time, deduce the change law of the important external loads of the wall through informatization, optimize the construction and design schemes, and realize the safety warning of the gabion retaining wall.

[0019] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. Description of the Drawings

[0020] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification, and are used together with the following specific embodiments to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the accompanying drawings:

[0021] Figure 1 is a flow block diagram of a method for correcting the default value of the earth pressure behind a gabion retaining wall according to an embodiment of the present invention;

[0022] Figure 2It is a schematic diagram of the placement of the earth pressure cell behind the gabion retaining wall in the embodiment of the present invention;

[0023] Figure 3 It is a schematic diagram of the analysis of the default value of the earth pressure behind the gabion retaining wall in the embodiment of the present invention;

[0024] Figure 4 It is a probability density distribution diagram of the corrected value of the earth pressure behind the gabion retaining wall in the embodiment of the present invention;

[0025] Among them, 1 - reinforced gabion retaining wall; 2 - earth pressure cell; 3 - high - toughness polyester yarn cluster grille; 4 - retaining wall elevation adjustment concrete block; 5 - gabion retaining wall structural fill. Specific implementation mode

[0026] The present invention will be described in detail below in conjunction with the embodiments shown in the drawings. It should be noted that these embodiments are not limitations of the present invention, and any equivalent transformation or substitution in function, method, or structure made by those of ordinary skill in the art according to these embodiments shall fall within the protection scope of the present invention.

[0027] Please refer to Figure 1 , this embodiment provides a method for correcting the default value of the earth pressure behind the gabion retaining wall, including the following steps:

[0028] S1: At least two monitoring sections are evenly spaced along the extension direction behind the reinforced gabion retaining wall 1, and each monitoring section is a vertical plane perpendicular to the reinforced gabion retaining wall 1 at its location. On each monitoring section, a plurality of earth pressure cells 2 are buried in sequence from low to high according to the construction sequence of the reinforced gabion retaining wall 1, and the monitoring data of each earth pressure cell 2 is recorded. Among them, the distance between two adjacent monitoring sections is 3 - 10 m; the heights of the plurality of earth pressure cells 2 in two adjacent monitoring sections are set in one - to - one correspondence.

[0029] The reinforced gabion retaining wall 1 is a gabion facing wall formed by stacking a plurality of gabion cages filled with gravel. The gabion cage is a box - shaped polygonal metal grid cage. The plurality of gabion cages are fixedly connected in sequence from bottom to top, and a high - toughness polyester yarn cluster grille 3 is arranged between two adjacent gabion cages up and down, and a retaining wall elevation adjustment concrete block 4 is arranged at the top of each stage of gabion cage. The plurality of earth pressure cells 2 are arranged between the reinforced gabion retaining wall 1 and the gabion retaining wall structural fill 5 by the hanging bag method, and the plurality of earth pressure cells 2 are respectively connected to a comprehensive acquisition instrument and are centrally powered by the power supply in the comprehensive acquisition instrument. The monitoring data on one monitoring section is defined as the data for engineering analogy.

[0030] S2: During the construction process, there may be cases where individual earth pressure cells 2 are damaged. Therefore, the earth pressure cells with normal functions are called surviving earth pressure cells. Among them, the damage rate of the earth pressure cells 2 does not exceed 30%. According to the monitoring data of the surviving earth pressure cells 2, the least squares method is used to draw the fitting line of the default value of the earth pressure behind the wall and the analog line of the same project. Specifically, taking the bottom of the gabion retaining wall at the same monitoring section as the coordinate origin, the measured pressure value of the earth pressure cell 2 as the x value, and the buried height corresponding to the earth pressure cell 2 as the y value, a coordinate system and a data point set (x, y) are constructed; assuming that the number of earth pressure cells 2 buried at the same monitoring section is n , the surviving quantity is m . If m < n , it indicates that there is a damaged pressure cell; if m = n , it indicates that there is no damaged pressure cell. The expression form of the least squares method used in this step is , where is the residual function, which can be a linear function or a non-linear function, i =1,2,… m ; w i are the optimal undetermined parameters; x i is the measured pressure value of the i th earth pressure cell; y i is the buried height of the i th earth pressure cell.

[0031] S3: Based on the design parameters of the reinforced gabion retaining wall 1 and the mechanical parameters of the backfill soil 5 of the gabion retaining wall structure, the theoretical line of the earth pressure behind the wall is calculated using the horizontal layer division method. Since there are three types of displacement modes for the wall of the reinforced gabion retaining wall 1, namely translation (T mode), rotation around the bottom of the wall (RB mode), and rotation around the top of the wall (RT mode), considering the soil arch effect and the shear stress between soil layers comprehensively, the horizontal layer division method is used in this step to construct the equilibrium equation of the micro element, and the theoretical line of the earth pressure behind the wall under any displacement mode can be obtained by cumulative summation.

[0032] S4: Calculate the cross cumulative density of the circle with radius r on the contour line of the default value of the earth pressure, the fitting line of the default value of the earth pressure, the analog line of the same project, and the theoretical line of the earth pressure. The earth pressure value corresponding to the maximum cross cumulative density is used as the best correction value of the default value of the earth pressure behind the reinforced gabion retaining wall 1. Specifically, a circular equation of the proximity r of the default value points of the earth pressure is constructed on one or more contour lines of the default value of the earth pressure, and the intersection length of this circular equation with the fitting line of the default value, the analog line of the same project, and the theoretical line is defined as the cross cumulative density; the earth pressure value corresponding to the center coordinate value corresponding to the maximum cross cumulative density is the best correction value of the measured default value of the earth pressure behind the gabion retaining wall. Embodiment

[0033] Taking a reinforced gabion retaining wall project in Yueyang as an example, as Figure 2 shown, the reinforced gabion retaining wall 1 is a galvanized gabion retaining wall with a high-wear-resistant organic coating, divided into three levels. The design heights of each level from bottom to top are 7m, 10m, and 10m respectively. The lengths of the high-tenacity polyester yarn bundle grids 3 are 20m, 18m, and 12m respectively. The designed slope of the gabion is 1:0.2, and the width of each platform is 2m. The large (length×width×height) size of the gabion cage is 3m×1m×1m, and the small (length×width×height) size is 3m×0.5m×0.8m. The backfill soil 5 of the gabion retaining wall structure is miscellaneous fill soil, with an elastic modulus of 4.5 Mpa, a comprehensive density of 18.5 kg / m 3 , an internal friction angle of 12°, and a cohesion of 9.7 kPa. The retaining wall elevation adjustment concrete block 4 is a concrete block with a compressive strength grade of C30, made of ordinary Portland cement, sand, and gravel.

[0034] The earth pressure cells 2 used in the reinforced gabion retaining wall 1 are JMZX-5020Am vibrating wire pressure cells, with a comprehensive range of 2 MPa, a sensitivity of 0.001 MPa, 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 burial depth of 12m, and the measured default value data group and the earth pressure data of the engineering analogy group behind the wall are as follows:

[0035]

[0036] As Figure 3 shown, using the least squares method, the fitting curve equation of the earth pressure default value group is calculated as: , the fitting correlation coefficient , the engineering analogy curve equation , the fitting correlation coefficient .

[0037] The reinforced gabion retaining wall belongs to a flexible retaining wall, and there are flexible deformation characteristics in actual engineering, generally manifested as rotation around the bottom of the wall. According to the Rankine earth pressure theory, the theoretical curve is obtained by using the horizontal layer method as: .

[0038] As Figure 4 shown, in this embodiment, the influence range of the point set is a circle with the default value point as the center and a radius of r. The longer the intersection length of this circle with the default value fitting line, the same engineering analogy line, and the theoretical line, the closer the adjacent relationship between this point and the three. At this time, define r = 1, then there is:

[0039] The cross cumulative density equation is .

[0040] Through numerical calculation, the maximum cross cumulative density is 5.928, and then the best correction value of the default value of the earth pressure behind the gabion retaining wall is obtained as 127.826 kPa.

[0041] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for correcting the default value of earth pressure behind a gabion retaining wall, characterized in that, Including: Step S1: At least two monitoring sections are evenly spaced along the extension direction of the reinforced gabion retaining wall (1) at the back of the retaining wall. On each monitoring section, multiple earth pressure cells (2) are buried in sequence from low to high according to the construction sequence of the reinforced gabion retaining wall (1), and the monitoring data of each earth pressure cell (2) are recorded. Step S2: According to the monitoring data of the remaining earth pressure cells (2), the least squares method is used to draw the fitting line of the default value of the earth pressure behind the wall and the analogy line of the same project. Step S3: Based on the design parameters of the reinforced gabion retaining wall (1) and the mechanical parameters of the fill soil (5) of the gabion retaining wall structure behind the wall, the theoretical line of the earth pressure behind the wall is calculated by the horizontal layer division method. Step S4: A circle with a radius of r of the default value point is constructed on one or more contour lines of the default value of the earth pressure, and the intersection length of the circle with the fitting line of the default value of the earth pressure, the analogy line of the same project, and the theoretical line of the earth pressure is defined as the intersection cumulative density; the earth pressure value corresponding to the center coordinate value corresponding to the maximum intersection cumulative density is used as the best correction value of the measured default value of the earth pressure behind the gabion retaining wall.

2. The method according to claim 1, wherein The reinforced gabion retaining wall (1) is a gabion facing wall formed by stacking multiple gabion cages filled with gravel. The multiple gabion cages are fixedly connected in sequence from bottom to top. A high-tenacity polyester yarn bundle grille (3) is arranged between two adjacent gabion cages up and down, and a retaining wall elevation adjustment concrete block (4) is arranged at the top of each stage of gabion cage.

3. The method according to claim 1, wherein The multiple earth pressure cells (2) are arranged behind the reinforced gabion retaining wall (1) by the hanging bag method, and the multiple earth pressure cells (2) are respectively connected to a comprehensive acquisition instrument and are centrally powered by the comprehensive acquisition instrument.

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 multiple earth pressure cells (2) 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 analogy data of the same project.

5. The method according to claim 1, wherein In the step S2: Taking the bottom of the gabion retaining wall at the same monitoring section as the coordinate origin, the measured pressure value of the earth pressure cell (2) as the x value, and the corresponding buried height of the earth pressure cell (2) as the y value, a coordinate system and a data point set (x, y) are constructed; assuming that the number of earth pressure cells (2) buried at the same monitoring section is n , and the remaining number is m , then m ≤ n ; The least squares expression form is , where L i ( x ) is the residual function,[[]]END]] i= 1, 2, …m ; w i is the optimal parameter to be determined; x i is the measured pressure value of the i th earth pressure cell; y i is the buried height of the i th earth pressure cell.[[]]END]] 6. The method according to claim 1, wherein In the step S3, there are three displacement modes for the wall body of the reinforced gabion retaining wall (1), namely translation, rotation around the bottom of the wall, and rotation around the top of the wall; considering the soil arch effect and the shear stress between soil layers comprehensively, the horizontal layer division method is used to construct the equilibrium equation of the micro-unit, and the theoretical line of the earth pressure behind the wall under any displacement mode is obtained by cumulative summation.

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