AU2020433233B2

AU2020433233B2 - System and method for monitoring and verifying global failure mode of soil and rock dual-element side slope

Info

Publication number: AU2020433233B2
Application number: AU2020433233A
Authority: AU
Inventors: Longde GUO; Zhixiao HAN; Yingxue HOU; Bin Jia; Lianxiang LI; Shengqun LI; Shilei ZHAO
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2020-03-02
Filing date: 2020-09-04
Publication date: 2023-06-08
Anticipated expiration: 2040-09-04
Also published as: WO2021174794A1; AU2020433233A1; CN111305286B; CN111305286A

Abstract

A monitoring and verifying system and method for an overall failure mode of a soil-rock dual-element side slope. The method comprises: 1) simulating a side slope by means of finite element software to obtain a slip line of the side slope; 2) making, according to a side slope construction scheme, a monitoring scheme of monitoring displacement changes of a slope top and a potential slip surface; 3) performing construction according to an arrangement scheme, and performing monitoring; 4) collating monitoring data, and analyzing displacement change conditions of the surface and the interior of the side slope; 5) determining the position of the slip line according to the monitored and analyzed displacement change conditions of the surface of the side slope, and drawing the slip line of the side slope according to a maximum displacement point inside the side slope; and 6) verifying, according to the obtained slip line of the side slope, the slip line obtained by a finite element method, and providing guidance for the subsequent side slope support structure construction by means of the finite element software.

Description

SYSTEM AND METHOD FOR MONITORING AND VERIFYING GLOBAL FAILURE MODE OF SOIL AND ROCK DUAL-ELEMENT SIDE SLOPE TECHNICAL FIELD

The present disclosure relates to the field of monitoring of failure modes of side slopes, in particular to a system and method for monitoring and verifying a global failure mode of a soil and rock dual-element side slope.

BACKGROUND

During the excavation of foundation pits and road construction, there will be a side slope with a soil layer on the top and rock on the bottom sometimes. It is called a soil and rock dual-element side slope. At present, the theoretical circle generally believes that a soil-layer side slope is an arc global failure mode; a global failure mode of a rock-layer side slope is relatively complicated, which is related to the rock properties and is diverse. There is a lack of research and consensus on the global failure mode of the soil and rock dual-element side slopes at home and abroad. In recent years, with the continuous development of Jinan's urban construction, four kinds of soil and rock dual-element foundation pit side slopes have appeared. According to different degrees of rock weathering, they are soil + fully weathered, soil + fully weathered + strongly weathered, soil + fully weathered + strongly weathered + moderately weathered, and soil + moderately weathered rock side slopes. Research on and determination of their global failure modes have important theoretical significance and engineering value to promote the progress of relevant technologies in China and the urban development and construction. However, currently, there is no method for determining the failure modes of the above-mentioned slopes in the prior art.

SUMMARY

In order to solve the technical problems in the prior art, the present disclosure discloses a system and method for monitoring and verifying a global failure mode of a soil and rock dual-element side slope. This monitoring and verification system and method verify that finite elements are calculated to obtain a failure mode of the soil and rock dual-element side slopes, and can also provide a guidance for the following construction of a supporting structure of the side slope. In order to achieve the above purpose, the technical solution of the present disclosure is as follows. In a first aspect, the embodiments of the present disclosure provide a method for monitoring and verifying a global failure mode of a soil and rock dual-element side slope, including the following steps: 1) simulating a side slope by means of finite element software, and obtaining a slip line of the side slope; 2) making, according to a side slope construction solution, a solution for monitoring displacement changes of a slope crest and a potential slip surface, including an arrangement solution of a deep soil displacement point, a slope crest displacement monitoring point, and a bench mark; 3) performing construction according to the arrangement solution determined in the step 2), and performing monitoring; 4) collating monitoring data, analyzing the displacement changes of a surface of and inside the side slope, particularly displacement changes of a soil and fully weathered rock interface and a fully weathered rock and strongly weathered rock interface; 5) determining, according to the monitored and analyzed displacement change of the surface of the side slope, a position of a slip line, and drawing, according to a maximum displacement point inside the side slope, a slip line of the side slope; and 6) comparing the slip line of the side slope obtained in the step 5) with the slip line obtained by a finite element method; if there is no difference, performing following supporting structure simulation by means of the finite element software and construction guidance; and if there is a difference, re-performing finite element simulation, and performing comparison again till no difference is found. As a further technical solution, an arrangement standard of the monitoring solution in the step 2) is as follows: 2-1) determining an arrangement solution of the bench mark: the bench mark needs to be arranged on the slope crest and located beyond an influence distance for side slope construction; the influence distance is decided by a height of the side slope; and according to the study, a maximum influence range of the construction on the displacement of the surface of the slope crest will not exceed the value of the thickness of a soil + fully weathered rock layer;

2-2) determining a region where the side slope construction has the greatest influence on the displacement of the surface of the slope crest: by taking an intersection line of the slope crest and a slope surface as a starting point, a region equivalent to the value of the thickness of the soil + fully weathered rock layer is measured away from the side slope construction direction; this part of region is the region where the side slope construction has the greatest influence on the displacement of the surface of the slope crest; and the bench mark is arranged beyond this region; 2-3) determining a deep soil displacement monitoring point: the purpose of the monitoring solution used in the present disclosure is to obtain the stability of the soil and rock dual-element side slope during the construction; since the side slope is composed of different strata, to verify whether an interface will suddenly change, most measurement points of an inclinometer tube are arranged at the interfaces of all the strata, and a few of the measurement points are arranged inside the soil layer; and generally, the monitoring range of the inclinometer tube should exceed a region where slippage occurs during the finite element calculation (at least one inclinometer tube should be arranged outside the slip surface), and monitoring points should be arranged at a soil and rock interface; and 2-4) determining a slope crest displacement monitoring point: the slope crest displacement monitoring point is arranged at positions that are 1 m and 2 m away from the intersection line of the slope crest and the slope surface. As a further technical solution, specific steps of the step 3) are as follows: 3-1) arranging a level at the bench mark; 3-2) selecting a round-head steel bar chiseled into the ground to a certain depth at the slope crest displacement monitoring point, obtaining a ground settlement of the monitoring point by observing the settlement of the round head of the steel bar, and obtaining a horizontal displacement of the monitoring point by observing a distance between the round head of the steel bar and the bench mark, the height of the round-head steel bar on the ground being convenient for observation; 3-3) respectively pre-burying, at the deep soil displacement point, the inclinometer tube matched with the inclinometer, wherein the inclinometer tube should measure data once every 1 m to ensure that the displacements of the soil layers at different depths are measured, and the inclinometer tube should be arranged at a stratum interface as much as possible; and a plurality of columns of deep soil displacement monitoring points are formed by disposing a plurality of columns of inclinometer tubes; and 3-4) obtaining that the soil around the upper part of the slip surface has a relatively large vertical displacement and a relatively small horizontal displacement so that layered settlement gauges are arranged at the deep soil displacement monitoring points on the left and right sides of the slip surface obtained by finite element simulation, the inclinometer tube and the settlement gauges being mounted simultaneously, with a mounting depth of 0.1 h. As a further technical solution, specific steps of the step 4) are as follows: 4-1) collecting and collating the data of the displacement monitoring points of each slope surface, and drawing a statistics table of horizontal displacement values of the slope crest and a statistics table of settlement of the slope crest; and 4-2) collecting and collating the data of each deep soil displacement monitoring point, and making statistics by using the statistics table of the displacements of the monitoring points. As a further technical solution, specific steps of the step 6) are as follows: verifying the slip line obtained by the finite element software according to the slip line of the side slope obtained in the step 5); if the difference between the two slip lines is not large, indicating that the calculation result of the finite element software is reliable; then using the finite element software to calculate the subsequent construction steps; and improving the construction positions and the number of supporting structures. In a second aspect, the embodiments of the present disclosure provide, on the basis of the above method, a system for monitoring and verifying a global failure mode of a soil and rock dual-element side slope, including: a surface displacement monitoring device mounted on a slope crest and used for monitoring a horizontal displacement and a vertical displacement of the slope crest; an inclinometer tube mounted inside side slope soil and at a soil and rock interface and used for monitoring horizontal displacements inside the side slope soil and at the soil and rock interface; a layered settlement gauge mounted on a slip surface of the side slope and used for monitoring a vertical displacement of the side slope soil; and a data processing device for acquiring the data monitored by the surface displacement monitoring device, the inclinometer and the layered settlement gauge; analyzing displacement changes of the surface of and inside the side slope, particularly the displacement changes at a soil and fully weathered rock interface and a fully weathered rock and strongly weathered rock interface; determining a position of a slip line according to the displacement change, obtained by monitoring and analysis, of the surface of the side slope, and drawing the slip line of the side slope according to a maximum displacement point inside the side slope; comparing the obtained slip line of the side slope with a slip line obtained by a finite element method; if there is no difference, performing following supporting structure simulation and construction guidance by means of the finite element software; and if there is a difference, re-performing finite element simulation, and performing comparison again till no difference is found. The system for monitoring and verifying the global failure mode of the soil and rock dual-element side slope provided by the present disclosure can learn about specific change values of the horizontal displacement and the vertical displacement of the slope crest by means of a surface displacement device mounted on the slope crest, learn about the horizontal displacement inside the side slope by means of the inclinometer tube, and learn about a change value of the vertical displacement inside the side slope by means of the layered settlement gauge, thus realizing comprehensive monitoring of the side slope, so as to timely and comprehensively learn about the displacement, inclination, and stress of the side slope to verify the accuracy of simulation. Compared with the existing system for monitoring a soil and rock side slope, the present disclosure has the beneficial effects: 1) The system for monitoring the global failure mode of the soil and rock dual-element side slope provided by the present disclosure can obtain the slip curve of the side slope by means of the monitoring data. In this way, the failure mode of the soil and rock dual-element side slope calculated by a finite element is verified, an important basis is provided for the calculation of safety coefficients of the side slope, and the design and maintenance work of the supporting structure can be guided. 2) By only using the inclinometer tube, the layered settlement gauge, and the round-head steel bars for monitoring the displacement of the surface of the slope crest, the monitoring system of the present disclosure has low cost and is easy to operate, unfound things are obtained with mature instruments, and the effect of a monitoring instrument is fully exerted.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings constituting a part of this application are used for providing further understanding for this application. Exemplary embodiments of this application and descriptions thereof are used for explaining this application and do not constitute any inappropriate limitation to this application. FIG. 1 is a flowchart of the present disclosure;

FIG. 2 is an instrument arrangement view of a system for monitoring a soil and rock dual-element side slope of the present disclosure; and FIG. 3 is a top view of a slope surface displacement monitoring point. In the drawings: 1: surface displacement device; 2: inclinometer tube; 3: arc-planar slip surface; 4: soil and fully weathered rock interface; 5: fully weathered rock and strongly weathered rock interface; 6: inclinometer tube reading platform; and 7: surface displacement monitoring point.

DETAILED DESCRIPTION

It should be noted that the following detailed descriptions are all exemplary and are intended to provide a further understanding of the present application. Unless otherwise specified, all technical and scientific terms used in the present disclosure have the same meaning as commonly understood by a person of ordinary skill in the art to which the present disclosure belongs. It should be noted that terms used herein are only for describing specific implementations and are not intended to limit exemplary implementations according to the present application. As used herein, the singular form is intended to include the plural form, unless the present disclosure clearly indicates otherwise. In addition, it should further be understood that terms "include" and/or "comprise" used in the present specification indicate that there are features, steps, operations, devices, assemblies, and/or combinations thereof. In recent years, with the continuous development of Jinan's urban construction, four kinds of soil and rock dual-element foundation pit side slopes have appeared. According to different degrees of rock weathering, the side slopes are soil + fully weathered, soil + fully weathered + strongly weathered, soil + fully weathered + strongly weathered + moderately

weathered, and soil + moderately weathered rock side slopes. Research on and determination of their global failure modes have important theoretical significance and engineering value to promote the progress of relevant technologies in China and the urban development and construction. Currently, there is no failure mode of the above-mentioned slopes in the prior art. In the present disclosure, according to finite element simulation results, the soil + fully weathered rock side slope shows a global failure behavior of arc slippage of the soil side slope, and the other three soil and rock dual-element side slopes basically show a global failure mode of arc + plane slippage. In order to verify and determine a global failure mode of the above soil and rock dual-element side slope, an inclinometer tube is used in combination with an existing monitoring technology to monitor horizontal displacements of deep soil at different positions on a cross section of the side slope; it is determined that the upper layer of soil at a series of soil and rock interfaces has a relatively large displacement; the displacement of the inclinometer tube at the rock and soil interface suddenly changes; and displacement sudden-change points are connected to build a slippage curve to determine the property of a planar slip surface of the soil and rock interface, which proves the global failure mode of the soil and rock side slope. In the present embodiment as a typical embodiment, as shown in FIG. 2, the system for monitoring and verifying a global failure mode of a soil and rock dual-element side slope includes a surface displacement device 1 (a specific arrangement method of which refers to FIG. 3. In FIG. 3, a surface displacement monitoring point 7 represents the mounting position of the surface displacement device 1) mounted at the slope crest and used for monitoring a horizontal displacement and a vertical displacement of the slope crest, an inclinometer tube 2 mounted inside soil, particularly at a soil and rock interface (corresponding to the soil and fully weathered rock interface 4 and the fully weathered rock and strongly weathered rock interface 5 in FIG. 2) and used for monitoring the displacement of the deep soil, a layered settlement gauge mounted near an arc-planar slip surface 3 and used for monitoring the vertical displacement of the soil, and a data processing device. Further, the surface displacement device 1 adopts a round-head steel bar. A specific mounting method includes: selecting a round-head steel bar chiseled into the ground to a certain depth at the slope crest displacement monitoring point, obtaining a ground settlement of the monitoring point by observing the settlement of the round head of the steel bar, and obtaining a horizontal displacement of the monitoring point by observing a distance between the round head of the steel bar and the bench mark. The height of the round-head steel bar on the ground is convenient for observation. Further, the specific arrangement method of the layered settlement gauge refers to FIG. 2. A plurality of layers of the layered settlement gauges are disposed along a height direction of the slope, and each layer includes a plurality of rows and a plurality of columns. Specifically, the soil around the upper part of the slip surface has a relatively large vertical displacement and a relatively small horizontal displacement so that layered settlement gauges are arranged at the deep soil displacement monitoring points on the left and right sides of the slip surface obtained by finite element simulation, the inclinometer tube and the settlement gauges being mounted simultaneously, with a mounting depth of 0.1 h. (In this example, according to finite element calculation, a cracking point on the slope crest of the slip surface is located at a horizontal distance between 1.1 h and 1.2 h from the slope toe, so the layered settlement gauge is mounted at the horizontal distances 1.1 h and 1.2 h from the slope toe). Further, a specific mounting method of the inclinometer tube 2 includes: respectively pre-burying the inclinometer tube at the deep soil displacement point, wherein the inclinometer tube 2 should measure data once every 1 m to ensure that the displacements of the soil layers at different depths are measured, and the inclinometer tube 2 should be arranged at a stratum interface as much as possible; and a plurality of columns of deep soil displacement monitoring points are formed by disposing a plurality of columns of inclinometer tubes. Further, the data processing device is used for acquiring the data monitored by the surface displacement monitoring device, the inclinometer and the layered settlement gauge; analyzing displacement changes of the surface of and inside the side slope, particularly the displacement changes at a soil and fully weathered rock interface and a fully weathered rock and strongly weathered rock interface; determining a position of a slip line according to the displacement change, obtained by monitoring and analysis, of the surface of the side slope, and drawing the slip line of the side slope according to a maximum displacement point inside the side slope; comparing the obtained slip line of the side slope with a slip line obtained by a finite element method; if there is no difference, performing following supporting structure simulation and construction guidance by means of the finite element software; and if there is a difference, re-performing finite element simulation, and performing comparison again till no difference is found. The system for monitoring and verifying the global failure mode of the soil and rock dual-element side slope disclosed in the present embodiment can learn about specific change values of the horizontal displacement and the vertical displacement of the slope crest by means of the surface displacement device mounted on the slope crest, learn about the horizontal displacement inside the side slope by means of the inclinometer tube, and learn about a change value of the vertical displacement inside the side slope by means of the layered settlement gauge, thus realizing comprehensive monitoring of the side slope, so as to timely and comprehensively learn about the displacement, inclination, and stress of the side slope to perform comparison with the slip line simulated by the finite element software. Based on the above system, the present embodiment further provides a monitoring and verification method. That is, a side slope is simulated by means of finite element software at first, and a slip line of the side slope is obtained; the side slope is then monitored, and a maximum displacement point inside the side slope is obtained by means of monitoring data; these points are connected to form a curve, thus obtaining a slip line of the side slope; the slip line obtained by the finite element software is verified with the obtained slip line of the side slope; if the difference between the two slip lines is not large, it is indicated that the calculation result of the finite element software is reliable; next, the finite element software is used to calculate the subsequent construction steps; and the construction positions and the number of supporting structures are improved. The method is specifically as follows: 1) a side slope is simulated by means of finite element software, and a slip line of the side slope is obtained; 2) a solution for monitoring displacement changes of a slope crest and a potential slip surface is made according to a side slope construction solution, including an arrangement solution of a deep soil displacement point, a slope crest displacement monitoring point, and a bench mark; 3) construction is performed according to the arrangement solution determined in the step 2), and monitoring is performed; 4) monitoring data is collated, and the displacement changes of a surface of and inside the side slope are analyzed, particularly displacement changes of a soil and fully weathered rock interface and a fully weathered rock and strongly weathered rock interface; 5) a position of a slip line is determined according to the monitored and analyzed displacement change of the surface of the side slope, and a slip line of the side slope is drawn according to a maximum displacement point inside the side slope; and 6) the slip line obtained by the finite element method is verified by the slip line of the side slope obtained in the step 5), and a guidance is provided for the following side slope supporting structure construction through the finite element software. Further, an arrangement standard of the monitoring solution in the step 2) is as follows. 2-1) An arrangement solution of the bench mark is determined: the bench mark needs to be arranged on the slope crest and located beyond an influence distance for side slope construction; the influence distance is decided by a height of the side slope; and according to the study, a maximum influence range of the construction on the displacement of the surface of the slope crest will not exceed the value of the thickness of a soil + fully weathered rock layer. 2-2) A region where the side slope construction has the greatest influence on the displacement of the surface of the slope crest is determined: by taking an intersection line of the slope crest and a slope surface as a starting point, a region equivalent to the value of the thickness of the soil + fully weathered rock layer is measured away from the side slope construction direction; this part of region is the region where the side slope construction has the greatest influence on the displacement of the surface of the slope crest; and the bench mark is arranged beyond this region. 2-3) A deep soil displacement monitoring point is determined: the purpose of the monitoring solution used in the present disclosure is to obtain a failure mode of the soil and rock dual-element side slope during the construction; since the side slope is composed of different strata, to verify whether an interface will suddenly change, most measurement points of an inclinometer tube are arranged at the interfaces of all the strata, and a few of the measurement points are arranged inside the soil layer. Generally, the monitoring range of the inclinometer tube should exceed a region where slippage occurs during the finite element calculation (at least one inclinometer tube should be arranged outside the slip surface), and monitoring points should be arranged at a soil and rock interface. 2-4) A slope crest displacement monitoring point is determined: the slope crest displacement monitoring point is arranged according to the finite element calculation result; one slope crest displacement monitoring point is arranged inside and outside a slip mass respectively; and in this example, the slope crest displacement monitoring point is arranged at positions that are 0.1 h and 0.2 h away from the intersection line of the slope crest and the slope surface. (h is a slope height.) Specific steps of the step 3) are as follows. 3-1) A level is arranged at the bench mark. 3-2) A round-head steel bar chiseled into the ground to a certain depth is selected at the slope crest displacement monitoring point, a ground settlement of the monitoring point is obtained by observing the settlement of the round head of the steel bar, and a horizontal displacement of the monitoring point is obtained by observing a distance between the round head of the steel bar and the bench mark, the height of the round-head steel bar on the ground being convenient for observation. 3-3) The inclinometer tube is respectively pre-buried at the deep soil displacement monitoring point, wherein the inclinometer tube should measure data once every 1 m to ensure that the displacements of the soil layers at different depths are measured, and the inclinometer tube should be arranged at a stratum interface as much as possible; and a plurality of columns of deep soil displacement monitoring points are formed by disposing a plurality of columns of inclinometer tubes. 3-4) The soil around the upper part of the slip surface has a relatively large vertical displacement and a relatively small horizontal displacement so that layered settlement gauges are arranged at the deep soil displacement monitoring points on the left and right sides of the slip surface obtained by finite element simulation, the inclinometer tube and the settlement gauges being mounted simultaneously, with a mounting depth of 0.1 h. (In this example, according to finite element calculation, a cracking point on the slope crest of the slip surface is located at a horizontal distance between 1.1 h and 1.2 h from the slope toe, so the layered settlement gauge is mounted at the horizontal distance 1.1 h and 1.2 h from the slope toe). Further, specific steps of the step 4) are as follows. 4-1) The data of the displacement monitoring points of each slope surface is collected and collated, and a statistics table of horizontal displacement values of the slope crest and a statistics table of settlement of the slope crest are drawn. Statistics table of horizontal displacement values of slope crest

Horizontal distances from the monitoring point to an intersection 0.1 h 0.2 h line of the slope crest and the slope surface Horizontal displacement value

Statistics table of settlement values of the slope crest

Horizontal distances from the monitoring point to an intersection 0.1 h 0.2 h line of the slope crest and the slope surface Settlement values

4-2) The data (the inclinometer tube and the layered settlement gauge) of each deep soil displacement monitoring point is collected and collated and is filled in the statistics table of the displacements of the monitoring point. Particularly, when the data of the inclinometer tube on the slope surface is collected, one needs to stand on a pre-built platform to read values. (The coordinates in the table reflect the position of the inclinometer tube in this example. In actual application, the position of the inclinometer tube is flexibly adjusted according to the thickness of each stratum, as long as it meets the requirement of 1-3.)

Statistics table of horizontal displacement values of the deep soil Horizontal distances from the monitoring

point to the slope toe 0.6 h 0.75 h 0.9 h 1.1 h 1.2 h Vertical distances from the monitoring point to the slope crest

0.1 h 0.3 h 0.5 h

Statistics table of settlement values of deep soil

Horizontal distances from the monitoring 1.1 h 1.2 h point to the slope toe Settlement values

Further, specific steps of the step 5) are as follows. According to the statistics tables of the displacements of the monitoring point of the step 5-1) and the step 5-2), the x, y coordinates of the maximum displacement points inside the side slope are determined, thus drawing a slip curve of the side slope (the maximum displacement is a magnitude value of a horizontal displacement vector and a vertical

displacement vector) and determining a failure mode of the side slope. For the convenience of understanding of the step 4-3), this example is particularly provided. Table 1 Statistics table of the horizontal displacement values of the slope crest

Horizontal distances from the monitoring point to an intersection 0.1 h 0.2 h line of the slope crest and the slope surface Horizontal displacement value 1.5 0 (mm)

Table 2 Statistics table of the settlement values of the slope crest

Horizontal distances from the monitoring point to an intersection 0.1 h 0.2 h line of the slope crest and the slope surface

Settlement values 7 0 (mm)

Table 3 Statistics table of the horizontal displacement values of the deep soil

Horizontal distances from the monitoring

point to the slope toe 0.6 h 0. 75 h 0.9 h 1.1 h 1.2 h Vertical distances from the monitoring point to the slope crest

0.1 h 1mm 0

0.3 h 7.2 9.6 mm 6 mm 0 0 mm

0.5 h 1.2 0 mm 0 mm 0 0 mm

Table 4 Statistics table of the settlement values of the deep soil

Horizontal distances from the monitoring 1.1 h 1.2 h point to the slope toe Settlement values 5 mm 0

In this example, the slope ratio is 1:1, with the slope toe serving as the origin of the coordinates. According to the data in Table 1 and Table 2, it is determined that the cracking point of the slope crest of the slip surface is between 0.1 h and 0.2 h of the horizontal distance from the slope crest, and an intermediate value is used. The coordinates of the cracking point are (1.15 h, h). According to the data in Table 3 and Table 4, there are: () At 0.1 h of the vertical distance from the slope crest, it is determined that the slip surface is between 1.1 h and 1.2 h of the horizontal distance from the slope toe, and an intermediate value is used, with the coordinates (1.15 h, 0.9 h); @ At 0.3 h of the vertical distance from the slope crest, it is determined that the slip surface is between 0.9 h and 1.1 h of the horizontal distance from the slope toe. Referring to the data at 0.75 h of the horizontal distance of the monitoring point from the slope toe, according to the linear law, the coordinates where the horizontal displacement value is 0 are (1.067 h, 0.7 h); and @ At 0.5 h of the vertical distance from the slope crest, it is determined that the slip surface is between 0.6 h and 0.75 h of the horizontal distance from the slope toe, and an intermediate value is used, with the coordinates (0.675 h, 0.5 h).

The curve drawn on the basis of the coordinates in the above figures is an arc slip line of the side slope, which is connected to the boundary between the fully weathered rock layer and the strongly weathered rock layer to obtain the slip line of the soil and rock dual-element side slope. It is then compared with the slip line obtained by the finite element method to verify the correctness of the result of the finite element method, and a support is provided for the next step of finite element analysis. The above descriptions are merely preferred embodiments of this application and are not intended to limit this application. For those skilled in the art, this application may have various modifications and changes. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of this application shall fall within the protection scope of this application.

Claims

CLAIMS What is claimed is:

1. A method for monitoring and verifying a global failure mode of a soil and rock dual element side slope, the method comprising: 1) simulating a side slope by means of finite element software, and obtaining a slip line of the side slope; 2) making, according to a side slope construction solution, a solution for monitoring displacement changes of a slope crest and a potential slip surface, comprising an arrangement solution of a deep soil displacement point, a slope crest displacement monitoring point, and a bench mark; 3) performing construction according to the arrangement solution determined in the step 2), and performing monitoring; wherein, specific steps of the step 3) are as follows: 3-1) arranging a level at the bench mark; 3-2) electing, at the slope crest displacement monitoring point, a round-head steel bar chiseled into the ground to a certain depth; obtaining a ground settlement of the monitoring point by observing the settlement of the round head of the steel bar; and obtaining a horizontal displacement of the monitoring point by observing a distance between the round head of the steel bar and the bench mark; 3-3) respectively pre-burying, at the deep soil displacement point, the inclinometer tube matched with the inclinometer; one inclinometer tube is arranged at intervals and is arranged at the stratum interface; and a plurality of columns of deep soil displacement monitoring points are formed by disposing a plurality of columns of inclinometer tubes; and 3-4) arranging layered settlement gauges at the deep soil displacement monitoring points on the left and right sides of the slip surface obtained by finite element simulation, and simultaneously mounting the layered settlement gauges and the inclinometer tubes; 4) collating monitoring data, analyzing the displacement changes of a surface of and inside the side slope, particularly displacement changes of a soil and fully weathered rock interface and a fully weathered rock and strongly weathered rock interface; 5) determining, according to the monitored and analyzed displacement change of the surface of the side slope, a position of a slip line, and drawing, according to a maximum displacement point inside the side slope, a slip line of the side slope; and 6) comparing the slip line of the side slope obtained in the step 5) with the slip line obtained by a finite element method; if there is no difference, simulating a following supporting structure by means of the finite element software, guiding the construction; and if there is a difference, re-performing finite element simulation, and performing comparison again till no difference is found.

2. The method for monitoring and verification according to claim 1, wherein in an arrangement solution of the bench mark in the step 1): determining a region where the side slope construction has the greatest influence on the displacement of the surface of the slope crest; the region is a region measured 1-fold more than the height of the side slope away from the side slope construction direction by taking an intersection line of the slope crest and the slope surface as a starting point; and the bench mark is arranged on the slope crest and located beyond an influence distance of the side slope construction.

3. The method for monitoring and verification according to claim 1, wherein most deep soil displacement monitoring points in the step 2) are arranged on interfaces of strata, and a few of deep soil displacement monitoring points are arranged inside a soil layer.

4. The method for monitoring and verification according to claim 1, wherein the slope crest displacement monitoring point in the step 2) is arranged at positions 1 m and 2 m from an intersection line of the slope crest and the slope surface.

5. The method for monitoring and verification according to claim 1, wherein specific steps of the step 4) are as follows: 4-1) collecting and collating the data of the displacement monitoring points of each slope surface, and drawing a statistics table of horizontal displacement values of the slope crest and a statistics table of settlement of the slope crest; and 4-2) collecting and collating the data of each deep soil displacement monitoring point, and making statistics by using the statistics table of the displacements of the monitoring points.

6. The method for monitoring and verification according to claim 5, wherein specific steps of the step 5) are as follows: according to statistics tables of the displacements of the monitoring point of the step 4-1) and the step 4-2), determining the x, y coordinates of the maximum displacement points inside the side slope, thus drawing a slip curve of the side slope and determining a failure mode of the side slope.

7. A system for monitoring and verifying a global failure mode of a soil and rock dual element side slope, comprising: a surface displacement monitoring device mounted on a slope crest and used for monitoring a horizontal displacement and a vertical displacement of the slope crest; an inclinometer tube mounted inside side slope soil and at a soil and rock interface and used for monitoring horizontal displacements inside the side slope soil and at the soil and rock interface; a layered settlement gauge mounted on a slip surface of the side slope and used for monitoring a vertical displacement of the side slope soil; and a data processing device for acquiring the data monitored by the surface displacement monitoring device, the inclinometer and the layered settlement gauge; analyzing displacement changes of the surface of and inside the side slope, particularly the displacement changes at a soil and fully weathered rock interface and a fully weathered rock and strongly weathered rock interface; determining a position of a slip line according to the displacement change, obtained by monitoring and analysis, of the surface of the side slope, and drawing the slip line of the side slope according to a maximum displacement point inside the side slope; comparing the obtained slip line of the side slope with a slip line obtained by a finite element method; if there is no difference, performing following supporting structure simulation and construction guidance by means of the finite element software; and if there is a difference, re-performing finite element simulation, and performing comparison again till no difference is found.