Soft rock slope instability failure detection and prevention and control method under stress hydraulic coupling effect

Abstract

The invention relates to a method for detecting, preventing and controlling instability failure of a soft rock slope under the action of stress hydraulic coupling, and belongs to the technical field of slope monitoring. The method comprises the following specific steps: drilling and sampling before soft rock mass construction, identifying a sample by using a camera device, and constructing a three-dimensional model of the soft rock mass; after the detection devices are installed on all the taken samples, the samples are placed in the soft rock mass again so as to be monitored in real time. The initial stress state of the soft rock slope can be determined by analyzing the three-dimensional model of the soft rock body and data collected in real time. And according to the three-dimensional model and the material characteristics of the soft rock, analyzing boundary conditions and key instability areas of slope instability. And corresponding prevention and control measures are taken according to the change of the monitoring data. According to the method, the change of the soft rock mass model data can be observed in real time, the change of the internal structure of the soft rock mass can be intuitively reflected, and more accurate data can be provided.

Description

Technical Field

[0001] The present invention relates to the technical field of slope monitoring, and particularly to a method for detecting, preventing and controlling the instability and failure of soft rock slopes under the coupling action of stress and hydraulics. Background Art

[0002] With the development of engineering construction, especially in mountainous areas or regions with complex terrains, the research on slope stability has become particularly important. In the prior art, the research on the instability and failure mechanism of soft rock slopes under the coupling action of stress and hydraulics is not yet perfect, lacking effective detection means and prevention and control measures, resulting in frequent slope accidents.

[0003] In China, the reinforcement measures for soft rock slopes usually include techniques such as setting platforms in levels, shotcrete bolt-net support or integral concrete support, etc. These techniques have improved the stability of soft rock slopes to a certain extent. However, these support techniques do not fully consider the problem of rainwater infiltration after slope excavation, as well as problems such as the disturbance that may be caused during the construction of anchor bolt drilling and the reduction of the strength of rock and soil masses due to rainwater infiltration into the rock mass around the hole wall. Therefore, these methods cannot accurately detect the specific reasons for the internal stability changes of soft rock slopes, nor can they provide precise prevention and control measures. In view of this, there is an urgent need to develop a new method that can detect, prevent and control the instability and failure of soft rock slopes under the coupling action of stress and hydraulics. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for detecting, preventing and controlling the instability and failure of soft rock slopes under the coupling action of stress and hydraulics, and to solve the technical problems that the existing prevention and control measures for soft rock slopes cannot accurately detect the factors of internal instability of soft rock masses and cannot provide precise prevention and control measures.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for detecting, preventing and controlling the instability and failure of soft rock slopes under the coupling action of stress and hydraulics, the method comprising the following steps:

[0007] Step 1: Drill several samples from the soft rock mass before construction and identify them using a camera device;

[0008] Step 2: Based on the identification data of the obtained samples, construct a three-dimensional model of the soft rock mass;

[0009] Step 3: Install monitoring devices on all the taken samples and re-insert the samples into the soft rock mass for continuous monitoring;

[0010] Step 4: Analyze the initial stress of the soft rock slope according to the three-dimensional model of the soft rock mass and the data collected in real time;

[0011] Step 5: Analyze the boundary conditions of slope instability and the key areas of instability based on the 3D model and the material properties of soft rock;

[0012] Step 6: Detect the data inside the soft rock in real time. When the numerical value of the soft rock changes and trends towards the instability condition, it indicates that the soft rock slope may be unstable;

[0013] Step 7: Take corresponding prevention and control measures according to the detected data changes until the detected data returns to the initial stress state.

[0014] Further, in Step 1, the camera device is composed of four cameras, a ring, two sample fixing ends, a telescopic cylinder and a connecting rod. The two sample fixing ends are respectively located at both ends of the connecting rod and are used to fix both ends of the sample. The ring surrounds the outside of the sample and can slide on the connecting rod. The four cameras are installed on the side of the ring, facing the east, south, west, and north directions of the sample respectively, and are set to aim at the sample. The telescopic end of the telescopic cylinder is connected to the ring, and by driving the ring to move back and forth, the four cameras can perform peripheral recognition on the sample during the movement.

[0015] Further, in Step 1, the sample is extracted by means of circular drilling. If the sample breaks during the drilling process, it is bonded and repaired with epoxy resin. Subsequently, the sample is recognized by four cameras, and the images captured by the four cameras are stitched together to obtain the video data of the sample periphery. Then, image recognition processing is performed on the video data to identify the stratification of the soft rock in the sample, the materials of the soft rock layers, and the distribution and size of the pores. Finally, the characteristic data related to the soft rock layer materials are automatically retrieved through the Internet.

[0016] Further, in Step 2, a 3D stereoscopic space model is constructed. This model is constructed according to the dimensions of the slope to be monitored at a corresponding ratio, and the 3D peripheral images of all samples are placed into the 3D stereoscopic space model. According to the different sampling positions of each sample, the sample is placed at the corresponding position points in the spatial model according to the ratio. In the 3D stereoscopic space model, the position points at the same depth of each sample are placed at the same height. The soft rock model inside the column of each sample is recognized, and a 3D model of the soft rock of each sample is obtained through the finite element analysis method. In the 3D stereoscopic space model, the points at the same height with the same properties or the same rock layers are connected by lines, and different line types or colors are used to distinguish the points at different heights to obtain the image color and void distribution in the sample. The connecting lines at the same height or with the same properties are rendered layer by layer, moving from the center of the sample outwards until the entire 3D stereoscopic space model is rendered, thereby obtaining the 3D model of the soft rock mass.

[0017] Furthermore, in step 3, a plurality of humidity sensors, stress sensors and displacement sensors are installed on the side of the sampled sample, and the transmission lines are connected to the outside, where a data acquisition device is provided to collect data in real time and transmit it back to the data processing system. In the initial acquisition stage, the collected data represents the initial state of the soft rock mass, that is, its stable state data.

[0018] Furthermore, in step 4, the internal data of the soft rock mass before construction is collected, and according to the material properties of the soft rock, the self-gravity of the soft rock is calculated. The material properties include hardness and density. The humidity data is detected by the humidity sensor, and the pore structure is identified to determine the structural stress of the soft rock in the initial state. The self-gravity and the structural stress are superimposed to obtain the initial stress state of the soft rock mass. Subsequently, the data related to the initial stress state is fused with the three-dimensional model of the soft rock mass, so that the stress data of the three-dimensional model of the soft rock mass can be updated in real time according to the changes in the detection data. The user can observe the stress condition in the three-dimensional model of the soft rock mass in real time through the display screen.

[0019] Furthermore, in step 5, according to the identified material properties of the soft rock at different depths, the strength reduction method is adopted to gradually reduce the shear strength parameters of the material, which include cohesion and internal friction angle, until the slope reaches the critical state, that is, failure occurs, and this is the instability condition of the slope. According to this instability condition, the boundary conditions of instability failure are applied. The three-dimensional model of the soft rock mass is backed up as the second three-dimensional model of the soft rock mass, and the failure conditions are simulated in the second three-dimensional model of the soft rock mass, so that the soft rock mass gradually approaches the critical state, thereby determining the area where instability occurs fastest and marking the key areas of instability. Finally, the simulated key areas of instability are integrated into the original three-dimensional model of the soft rock mass to form a three-dimensional model of the soft rock mass with area markings.

[0020] Furthermore, in step 6, the collected data is imported into the three-dimensional model of the soft rock mass with area markings in real time. According to the changes in the collected data, it is determined whether the data trend is consistent with the simulated instability direction. If it is consistent, the management personnel are notified immediately, and the data that may cause instability is transmitted to the management personnel.

[0021] Furthermore, in step 7, if the instability data indicates an increase in humidity, the measures of drilling and pumping water should be implemented. Specifically, holes are drilled at the bottom to achieve vacuum pumping, and holes are drilled at the top to introduce nitrogen. After the humidity returns to the initial level, the pumping holes and nitrogen injection holes should be sealed. If movement or stress increase is detected and it is judged to be caused by vibration or internal oxidation leading to loosening, the bolt reinforcement measures should be taken, and cement slurry should be injected into the bolts for reinforcement until the data collected subsequently is re-stabilized within the initially set error range.

[0022] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects:

[0023] The present invention collects samples at different points of soft rock, performs pattern recognition on the samples, and obtains a three-dimensional model of the soft rock of the samples through finite element method analysis. All the samples are combined, and a model of the entire soft rock mass is generated through recognition and rendering. The samples are placed back into the soft rock mass and data of the soft rock mass are collected in real time. The collected data are put into the model of the soft rock mass, and the change of the model data of the soft rock mass can be seen in real time. The internal structure change of the soft rock mass can be seen more directly, and the data are more accurate. Corresponding protective measures are taken according to the change of the data. At the same time, the protective effect is judged according to the real-time data during the protection process, so as to achieve precise protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flowchart of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following preferred embodiments are cited with reference to the accompanying drawings, and the present invention is further described in detail. However, it should be noted that many details listed in the specification are only for enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0026] As Figure 1 shown, a method for detecting and preventing the instability and failure of a soft rock slope under the action of stress and hydraulic coupling, the method comprising the following steps:

[0027] Step 1: Drill several samples from the soft rock mass before construction and use a camera device for recognition. The camera device consists of four cameras, a ring, two sample fixing ends, a telescopic cylinder and a connecting rod. The two sample fixing ends are respectively located at both ends of the connecting rod and are used to fix both ends of the sample. The ring surrounds the outside of the sample and can slide on the connecting rod. The four cameras are installed on the side of the ring and are respectively oriented towards the east, south, west and north directions of the sample and are set to aim at the sample. The telescopic end of the telescopic cylinder is connected to the ring, and the ring is driven to move reciprocally, so that the four cameras perform peripheral recognition on the sample during the movement. Through the telescopic movement of the telescopic cylinder, the four cameras are driven to move slowly and perform three-dimensional recognition on the sample, and it can be ensured that a 360-degree space can be photographed from four directions.

[0028] Samples are extracted by circular drilling. If a sample breaks during drilling, it is glued and repaired with epoxy resin. Subsequently, the sample is identified by four cameras, and the images captured by the four cameras are stitched together to obtain video data of the sample perimeter. Then, image recognition processing is performed on the video data to identify the stratification of soft rock in the sample, the soft rock layer materials, and the distribution and size of pores. Finally, characteristic data related to the soft rock layer materials is automatically retrieved from the Internet.

[0029] Step 2: Based on the identification data of the obtained samples, construct a three-dimensional model of the soft rock mass. Construct a three-dimensional space model. This model is constructed according to the size of the slope to be monitored at a corresponding ratio. The three-dimensional perimeter images of all samples are placed into the three-dimensional space model. According to the different sampling positions of each sample, the sample is placed at the corresponding ratio position point in the space model. In the three-dimensional space model, the position points of the same depth of each sample are placed at the same height. Identify the soft rock model inside the column of each sample, and obtain the three-dimensional model of the soft rock of each sample through the finite element analysis method. In the three-dimensional space model, connect the points of the same nature or the same rock layer at the same height with lines, and use different line types or colors to distinguish the points at different heights to obtain the image color and void distribution in the sample. Render the connection lines of the same height or the same nature, and move outward from the center of the sample until the entire three-dimensional space model is rendered, thereby obtaining the three-dimensional model of the soft rock mass.

[0030] The size of the three-dimensional model is determined according to the size of the slope to be detected, and a corresponding ratio is set according to the size of the slope. When the slope is large, the ratio will be relatively large, but the internal detailed content can be viewed by zooming.

[0031] Step 3: Install monitoring devices on all the extracted samples and re-insert the samples into the soft rock mass for continuous monitoring. Install multiple humidity sensors, stress sensors, and displacement sensors on the side of the sampled samples, and connect the transmission lines to the outside. An acquisition device is provided outside to collect data in real time and transmit it back to the data processing system. In the initial acquisition stage, the collected data represents the initial state of the soft rock mass, that is, its stable state data.

[0032] Step 4: Analyze the initial stress of the soft rock slope based on the three-dimensional model of the soft rock mass and the real-time collected data. Collect the internal data of the soft rock mass before construction, and calculate the self-weight of the soft rock according to the material properties of the soft rock. The material properties include hardness and density. Detect the humidity data through a humidity sensor and identify the pore structure to determine the structural stress of the soft rock in the initial state. Superimpose the self-weight and the structural stress to obtain the initial stress state of the soft rock mass. Subsequently, fuse the data related to the initial stress state with the three-dimensional model of the soft rock mass, so that the stress data of the three-dimensional model of the soft rock mass can be updated in real time according to the changes in the detection data. The user can observe the stress condition in the three-dimensional model of the soft rock mass in real time through the display screen. The data collection transmits the data back to the management end of the service system through wireless transmission, and then transmits the data from the server to the model.

[0033] Step 5: Analyze the boundary conditions of slope instability and the key instability areas based on the three-dimensional model and the material properties of the soft rock. According to the identified material properties of the soft rock at different depths, use the strength reduction method to gradually reduce the shear strength parameters of the material, which include cohesion and internal friction angle, until the slope reaches the critical state, that is, failure occurs, and this is the instability condition of the slope. According to this instability condition, apply the boundary conditions of instability failure. Back up the three-dimensional model of the soft rock mass as the second three-dimensional model of the soft rock mass, simulate the failure conditions in the second three-dimensional model of the soft rock mass, make the soft rock mass gradually tend to the critical state, so as to determine the area where instability occurs fastest, and mark the key instability areas. Finally, integrate the simulated key instability areas into the original three-dimensional model of the soft rock mass to form a three-dimensional model of the soft rock mass with area markings.

[0034] Step 6: Real-time detect the data inside the soft rock mass. When the numerical value of the soft rock mass changes and approaches the instability condition, it indicates that the soft rock slope may be unstable. Import the collected data into the three-dimensional model of the soft rock mass with area markings in real time. According to the changes in the collected data, determine whether the data trend is consistent with the simulated instability direction. If it is consistent, quickly notify the management personnel and transmit the data that may cause instability to the management personnel. The data transmission is all through wireless transmission, which is convenient and fast.

[0035] Step 7: Take corresponding prevention and control measures according to the detected data changes until the detected data returns to the initial stress. If the instability data indicates an increase in humidity, the measures of drilling holes for pumping water should be implemented. Specifically, holes are drilled at the bottom to achieve vacuum pumping, while holes are drilled at the top for introducing nitrogen. After the humidity returns to the initial level, the pumping holes and nitrogen-introducing holes should be sealed. If movement or stress increase is monitored and it is judged to be caused by vibration or internal oxidation resulting in loosening, the bolt reinforcement measures should be taken, and cement slurry should be injected into the bolts for reinforcement until the subsequently collected data is re-stabilized within the initially set error range. Different data errors are set according to different scenarios. For those that do not reach the instability critical state, no treatment is required. However, for some highways with traffic flow greater than the set value, smaller error data can be set according to requirements. When the error data changes exceed the limit, corresponding treatment measures need to be taken.

[0036] By collecting samples at different points of the soft rock, and through graphic recognition of the samples and finite element method analysis, a three-dimensional model of the soft rock of the sample is obtained. Then all the samples are combined, and a model of the entire soft rock mass is generated through recognition and rendering. The samples are put back into the soft rock, and the data of the soft rock mass is collected in real time. The collected data is put into the model of the soft rock mass, so that the change of the model data of the soft rock mass can be understood in real time, and the internal structural change of the soft rock mass can be grasped more directly. Corresponding protection measures are given according to the data change.

[0037] Matters not covered by this invention are well-known technologies.

[0038] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for detecting and preventing instability of soft rock slopes under stress-hydraulic coupling, characterized in that: The method comprises the following steps: Step 1: Take several samples from the soft rock before construction and use a camera device to identify them; Step 2: construct a three-dimensional model of the soft rock mass based on the identification data of the obtained samples; Step 3: Install monitoring equipment on all removed samples and reinsert the samples into the soft rock mass for continuous monitoring; Step 4: Analyze the initial force of the soft rock slope based on the 3D model of the soft rock mass and the real-time collected data; Step 5: Analyze the boundary conditions and key areas of slope instability based on the 3D model and the material properties of soft rock; Step 6: Real-time detection of data in the soft rock mass. When the soft rock mass value changes and moves toward instability, it indicates that the soft rock slope may become unstable. Step 7: Take corresponding prevention and control measures according to the changes in the test data until the test data returns to the initial force.

2. The method for detecting and preventing instability and damage of soft rock slopes under stress-hydraulic coupling according to claim 1 is characterized in that: in step 1, the camera device consists of four cameras, a circular ring, two sample fixing ends, a telescopic cylinder and a connecting rod. The two sample fixing ends are respectively located at the two ends of the connecting rod and are used to fix the two ends of the sample. The circular ring surrounds the outside of the sample and can slide on the connecting rod. The four cameras are installed on the side of the circular ring, facing the east, south, west and north directions of the sample respectively, and are set to align with the sample. The telescopic end of the telescopic cylinder is connected to the circular ring, which is driven to move back and forth, so that the four cameras can perform peripheral identification of the sample during the movement.

3. The method for detecting and preventing instability and damage of soft rock slopes under stress-hydraulic coupling according to claim 2 is characterized in that: in step 1, a circular drilling method is used to extract samples. If the sample is broken during the drilling process, it is bonded and repaired with epoxy resin. Subsequently, the sample is identified by four cameras, and the images captured by the four cameras are spliced ​​to obtain video data of the periphery of the sample. Then, image recognition processing is performed on the video data to identify the stratification of soft rock in the sample, the soft rock layer material, and the distribution and size of pores. Finally, the characteristic data related to the soft rock layer material is automatically retrieved through the Internet.

4. The method for detecting and preventing the instability and damage of soft rock slopes under the action of stress-hydraulic coupling according to claim 1 is characterized in that: in step 2, a three-dimensional spatial model is constructed, which is constructed according to the corresponding proportion according to the size of the slope to be monitored, and the three-dimensional peripheral images of all samples are placed in the three-dimensional spatial model. According to the different sampling positions of each sample, the samples are placed at the corresponding proportions in the spatial model. In the three-dimensional spatial model, the positions of each sample at the same depth are placed at the same height, and the soft rock model inside the column of each sample is identified, and the three-dimensional model of the soft rock of each sample is obtained by finite element analysis. In the three-dimensional spatial model, the points of the same nature or the same rock layer at the same height are connected with lines, and different line types or colors are used to distinguish points at different heights to obtain the image color and gap distribution in the sample. The connecting lines of the same height or the same nature are rendered in layers, moving outward from the center of the sample until the entire three-dimensional spatial model is rendered, thereby obtaining a three-dimensional model of the soft rock mass.

5. The method for detecting and preventing the instability of soft rock slopes under the action of stress-hydraulic coupling according to claim 1 is characterized in that: in step 3, multiple humidity sensors, stress sensors and displacement sensors are installed on the side of the sample, and the transmission line is connected to the outside, and a collection device is provided outside to collect data in real time and transmit it back to the data processing system. In the initial collection stage, the collected data represents the initial state of the soft rock mass, that is, its stable state data.

6. The method for detecting and preventing instability and damage of soft rock slopes under stress-hydraulic coupling according to claim 1 is characterized in that: in step 4, the internal data of the soft rock mass before construction is collected, and the self-weight of the soft rock is calculated based on the material properties of the soft rock, the material properties including hardness and density, the humidity data is detected by a humidity sensor, and the pore structure is identified to determine the structural stress of the soft rock in the initial state, the self-weight and the structural stress are superimposed to obtain the initial stress state of the soft rock mass, and then the data related to the initial stress state are fused with the three-dimensional model of the soft rock mass, so that the force data of the three-dimensional model of the soft rock mass can be updated in real time according to the changes in the detection data, and the user can observe the force condition in the three-dimensional model of the soft rock mass in real time through the display screen.

7. The method for detecting and preventing instability of soft rock slopes under stress-hydraulic coupling according to claim 1 is characterized in that: In step 5, according to the material properties of the identified soft rocks at different depths, the strength reduction method is used to gradually reduce the shear strength parameters of the material, which include cohesion and internal friction angle, until the slope reaches a critical state, that is, failure occurs. This is the instability condition of the slope. According to the instability condition, the instability failure boundary condition is applied, and the three-dimensional model of the soft rock mass is backed up as a second three-dimensional model of the soft rock mass. The failure conditions are simulated in the second three-dimensional model of the soft rock mass, so that the soft rock mass gradually tends to a critical state, thereby determining the area where instability occurs fastest, and marking the key areas of instability. Finally, the simulated key areas of instability are integrated into the original three-dimensional model of the soft rock mass to form a regionally marked three-dimensional model of the soft rock mass.

8. The method for detecting and preventing instability of soft rock slopes under stress-hydraulic coupling described in claim 1 is characterized in that: Step 6, the collected data is imported into the three-dimensional model of the soft rock mass with regional annotation in real time, and based on the changes in the collected data, it is determined whether the data trend is consistent with the simulated instability direction. If it is consistent, the management personnel are notified quickly, and the data that may cause instability are transmitted to the management personnel.

9. The method for detecting and preventing instability of soft rock slopes under stress-hydraulic coupling according to claim 1 is characterized in that: in step 7, if the instability data indicates an increase in humidity, drilling and pumping measures should be implemented, with holes drilled at the bottom to achieve vacuum pumping, and holes drilled at the top to introduce nitrogen. After the humidity returns to the initial level, the pumping holes and nitrogen holes should be sealed. If movement or increased stress is monitored and it is determined to be loosening caused by vibration or internal oxidation, anchor reinforcement measures should be taken and cement slurry should be injected into the anchor for reinforcement until the subsequently collected data stabilizes within the error range set initially.

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