A long-term stability dynamic evaluation method for a waste dump based on a sky-ground-room combined analysis

Abstract

This invention provides a dynamic assessment method for the long-term stability of spoil heaps based on a combined air-ground-indoor analysis, belonging to the field of spoil heap stability assessment. First, by using PS-InSAR deformation monitoring and combining it with elevation data before and after construction, double integrals are performed to obtain the volume change and soil density of the spoil heap at different times, addressing the issue of soil density changing over time. Then, by combining on-site monitoring and indoor tests, the soil moisture content and compaction degree of the spoil heap at different times are obtained, addressing the issue of compaction degree changing over time. Second, based on indoor tests, functional relationships between soil physical property parameters and moisture content and compaction degree are constructed, addressing the issue of soil physical property parameters changing with the environment. Finally, based on the strength reduction method, a functional relationship between the stability safety factor and moisture content and compaction degree is constructed, addressing the problem that existing assessments cannot respond promptly to changes in on-site conditions, providing a reliable assessment method for the dynamic assessment of the long-term stability of spoil heaps.

Description

Technical Field

[0001] This invention relates to the field of long-term stability dynamic assessment technology for large-scale spoil heaps in geotechnical engineering, and particularly to a method for long-term stability dynamic assessment of spoil heaps based on a combined air-ground-chamber analysis. Background Technology

[0002] In recent years, with the continuous advancement of large-scale infrastructure, a large amount of waste soil and waste material will inevitably be generated. However, a large amount of waste soil and waste material is difficult to be directly utilized and transformed. Only a small portion is used as topsoil for vegetation. Most of it is filled in valleys and slopes near the project, forming artificial slopes, also known as waste disposal sites. At the same time, the safety and stability assessment of waste disposal sites after filling has always been one of the challenges faced by the project. The main difficulties are: (1) To calculate the slope stability using the currently accepted methods in geotechnical engineering, it is necessary to know the physical and mechanical properties of the soil. However, these parameters are constantly changing over time and are difficult to determine; (2) The stability safety factor of the waste disposal site is dynamically changing under the influence of environmental factors (rainfall, earthquakes, etc.). Timely updating of the stability safety factor of the waste disposal site is of great significance for whether protective measures need to be taken for the waste disposal site and for the downstream engineering structures and people to avoid risks in a timely manner.

[0003] For example, Chinese patent CN118364543B, "A Method and System for Early Warning of Slope Stability and Drainage Condition in Water-Rich Areas," uses the strength reduction method to calculate slope stability under different influencing factors. It fails to mention the soil physical property parameters required for the calculation and does not consider the dynamic changes of these parameters under different influencing factors, resulting in a stability safety factor that does not accurately reflect real-world conditions. Secondly, Chinese patent CN118569124A, "A Method and System for Early Warning of Reservoir Bank Slopes Based on Process Stability Analysis," calculates the slope stability coefficient in S1 (initial analysis step) and S2 / S3 (seepage simulation), and in S4 (simulating the seepage field and calculating the slope stability coefficient within the current analysis step). However, it also fails to mention the soil physical property parameters required for the calculation and does not consider the dynamic changes of these parameters under different influencing factors, making the stability safety factor inconsistent with the actual conditions of spoil heap soil.

[0004] Therefore, this invention proposes a dynamic assessment method for the long-term stability of spoil heaps based on a combined air-ground-chamber analysis to address the difficulties in the stability assessment of spoil heaps mentioned above. This provides a new solution for revealing the dynamic assessment of the long-term stability of spoil heaps under the influence of environmental factors (rainfall, earthquakes, etc.). Summary of the Invention

[0005] In order to provide a dynamic assessment of the long-term stability of spoil disposal sites under the influence of environmental factors, this invention provides a dynamic assessment method for the long-term stability of spoil disposal sites based on a combined analysis of space, ground and laboratory. (1) By performing PS-InSAR analysis on remote sensing satellite images of spoil disposal sites in the study area, the deformation characteristics of spoil disposal sites in the study area are obtained. Further analysis is performed to obtain the settlement and volume change of spoil disposal sites. Combined with the on-site in-situ monitoring results, the soil compaction degree and moisture content of spoil disposal sites at different times are obtained, providing dynamic soil-related parameters for the stability assessment of spoil disposal sites. In addition, the InSAR satellite image re-enhancing cycle is short, and the PS-InSAR inversion results can reach the millimeter level, which can meet the requirements for the dynamic assessment of the long-term stability of spoil disposal sites. (2) Based on the indoor soil physical property test, a multivariate regression analysis was conducted to establish the functional relationship between the soil physical property parameters cohesion, internal friction angle, elastic modulus and Poisson's ratio and soil compaction degree and moisture content. The strength reduction method analysis was conducted to obtain the dynamic stability safety factor of the spoil disposal site under the influence of environmental factors in the study area. The stability of the spoil disposal site was judged to determine whether it meets the requirements, and whether relevant reinforcement measures should be taken for the spoil disposal site.

[0006] This invention is achieved through the following technical solution:

[0007] A dynamic assessment method for the long-term stability of spoil heaps based on a combined air-ground-chamber analysis includes the following steps:

[0008] S1. Obtain the elevation data of the spoil disposal site before and after construction. Perform a double integral based on the elevation difference between the two construction periods to obtain the initial volume V0 of the spoil disposal site, and then obtain the initial density ρ0 of the soil.

[0009] S2. Using PS-InSAR technology, the time series of surface deformation at different periods of the spoil heap in the study area are obtained, and the surface subsidence is calculated. Then, the difference between the elevation value after the completion of the spoil heap obtained in step S1 and the surface subsidence is double integrated to obtain the volume change ΔV of the spoil heap. i Thus, the soil density ρ is obtained. i ;

[0010] S3. The surface displacement and soil moisture content are obtained by using GNSS monitoring stations and moisture content sensors deployed in situ.

[0011] S4. The maximum dry density of the soil was obtained based on the indoor soil compaction test. At the same time, the compaction degree of the spoil heap soil was obtained based on the soil density obtained in step S2 and the soil moisture content obtained in step S3.

[0012] S5. Based on the maximum dry density and compaction degree of the soil in the waste disposal site obtained in step S4, conduct indoor triaxial shear tests on the soil under different moisture contents and different compaction degrees to obtain the soil physical property parameters under different moisture contents and different compaction degrees. The soil physical property parameters include cohesion, internal friction angle, elastic modulus, and Poisson's ratio.

[0013] S6. Based on the soil physical property parameters obtained in step S5, perform multiple regression analysis to establish fitting formulas for the soil physical property parameters as a function of water content and compaction degree.

[0014] S7. The soil compaction degree and moisture content obtained in real time through steps S4 and S3 are substituted into the fitting formula of the soil physical property parameters as a function of moisture content and compaction degree in step S6 to obtain the dynamically changing soil physical property parameters. The dynamically changing soil physical property parameters include cohesion, internal friction angle, elastic modulus and Poisson's ratio. Then, the strength reduction method is used to perform stability analysis of the spoil heap to obtain the dynamic stability safety factor of the spoil heap.

[0015] S8. Using the dynamic stability safety factor of the spoil disposal site obtained in step S7, perform multiple regression analysis to establish a fitting formula for the dynamic stability safety factor of the spoil disposal site as a function of compaction degree and moisture content, thereby dynamically assessing the long-term stability of the spoil disposal site in the future.

[0016] Preferably, step S1 specifically includes:

[0017] The elevation H0(x,y) of the original ground surface before the construction of the spoil disposal site in the study area was obtained, and the elevation H of the top surface of the spoil disposal site after construction was obtained. f (x,y), the initial volume V0 and initial density ρ0 of the spoil disposal site soil are obtained according to the following formula;

[0018]

[0019]

[0020] Where V0 is the initial volume of the spoil heap soil, ρ0 is the initial density of the spoil heap soil, H0(x,y) is the elevation of the original ground before the construction of the spoil heap, and H f (x,y) represents the elevation of the top surface of the spoil heap after completion, and m0 represents the mass of the spoil heap after it is filled.

[0021] Preferably, step S2 specifically comprises:

[0022] First, the geographical location of the spoil heap in the study area was determined. Then, satellite data of the spoil heap at different times was downloaded from the official satellite data website. Next, remote sensing image processing software was used to process and analyze the satellite images to obtain deformation characteristic points of the spoil heap at different times. Further, Kriging interpolation analysis was performed on the processed deformation characteristic points to obtain the deformation results of the study area. Finally, the elevation H of the spoil heap's top surface at different times during the settlement process was calculated using the obtained deformation results. i (x, y), and then the volume change ΔV of the spoil heap at different times is obtained by the following formula. i and soil density ρ i .

[0023]

[0024]

[0025] Wherein, △V i and ρ i These represent the volume change and soil density of the spoil heap at different times, respectively. V0 is the initial volume of the spoil heap, m0 is the mass of the spoil heap after completion, and H... i (x, y) represents the elevation of the top surface of the spoil heap at different stages of the settling process, H f (x,y) represents the elevation of the top surface of the waste disposal site after completion.

[0026] Preferably, step S4 specifically comprises:

[0027] The maximum dry density ρ of the soil was obtained based on indoor soil compaction tests. dmax Simultaneously, based on the soil density ρ of the spoil heap at different times obtained in step S2... i The soil moisture content w at different times of the spoil heap obtained in step S3 i The value can be substituted into the following formula to obtain the soil compaction degree λ of the spoil heap at different times. i ,

[0028]

[0029] Where, ρ dmax λ represents the maximum dry density of the soil in the spoil heap. i ρ represents the soil compaction degree of the spoil heap at different times. i For the soil density of the spoil heap at different times, w i The moisture content of the soil in the spoil heap at different times.

[0030] Preferably, step S5 specifically comprises:

[0031] Based on the maximum dry density and compaction degree of the soil in the spoil heap obtained in step S4, indoor triaxial shear tests were conducted on the soil under different moisture contents and compaction degrees. The specific steps of the triaxial shear test are as follows: First, cylindrical soil samples with different compaction degrees and moisture contents were prepared; then, the samples were fitted with a rubber diaphragm and installed in the pressure chamber of the triaxial shear test apparatus; next, the pressure chamber was filled with water, and the soil samples were subjected to saturation or unsaturation operations, as well as different confining pressures. A consolidation-drained test was used to conduct the shear test at a shear rate of 1 mm / min until the axial strain of the sample reached 20%, at which point loading was stopped; finally, the physical property parameters of the spoil heap soil under different moisture contents and compaction degrees were analyzed, including cohesion c. i internal friction angle φ i Elastic modulus E i Poisson's ratio v i .

[0032] Preferably, step S6 specifically includes:

[0033] Based on step S5, the physical property parameters of the waste soil under different moisture contents and different compaction conditions, including cohesion c, were obtained. i internal friction angle φ i Elastic modulus E i Poisson's ratio v i Perform multiple regression analysis and select the coefficient of determination R. 2 The fitting formula closest to 1 can be used to obtain the fitting formula for the changes in soil physical properties with compaction degree and water content. The functional expression of the relevant formula is shown below.

[0034]

[0035]

[0036]

[0037]

[0038] Among them, c i φ i E i v i These represent the cohesion, angle of internal friction, elastic modulus, Poisson's ratio, and λ of soil under different moisture contents and compaction degrees. i and w i For the function f(λ) i , w i The independent variable of f(λ) i , w i ) is about λ i and w i The changing functional relationship.

[0039] This invention also provides the application of the above-mentioned dynamic evaluation method for long-term stability of spoil disposal sites based on combined sky-ground-chamber analysis in the stability evaluation of spoil disposal sites.

[0040] The present invention has the following beneficial effects:

[0041] (1) The deformation characteristics of the spoil disposal site in the study area at different times were obtained by using PS-InSAR technology. Combined with the original ground elevation and the ground elevation after completion, the soil density of the spoil disposal site at different times was calculated. Furthermore, the soil moisture content of the spoil disposal site at different times and the maximum dry density of the soil obtained by the indoor compaction test were obtained through on-site in-situ monitoring, and the soil compaction degree of the spoil disposal site at different times was indirectly obtained.

[0042] (2) Through indoor soil strength test and multiple regression analysis, fitting formulas were established for the soil physical property parameters cohesion, internal friction angle, elastic modulus and Poisson's ratio as a function of soil compaction degree and moisture content.

[0043] (3) Based on the combination of PS-InSAR technology, on-site in-situ monitoring and indoor tests, the physical property parameters of the dynamic changes of the spoil disposal site soil at different times were obtained. The dynamic physical property parameters include soil moisture content, compaction degree, cohesion, internal friction angle, elastic modulus and Poisson's ratio. The obtained physical property parameters of the dynamic changes of the spoil disposal site soil at different times were input into the finite difference software for strength reduction analysis, and the stability safety factor of the spoil disposal site at different times, i.e., the dynamic stability safety factor, was obtained.

[0044] In summary, the method proposed in this invention provides a feasible research approach for the long-term dynamic safety assessment of spoil disposal sites under the influence of environmental factors, and has significant practical implications for the safety and stability assessment of spoil disposal sites. Attached Figure Description

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0046] Figure 1 A general technical roadmap for the dynamic assessment of the long-term stability of spoil disposal sites;

[0047] Figure 2 This is a schematic diagram of the PS-InSAR deformation monitoring technology process;

[0048] Figure 3 A flowchart illustrating the process of establishing fitting formulas for the physical property parameters of soil in spoil disposal sites;

[0049] Figure 4 A schematic diagram for solving the dynamic safety factor of the long-term stability of the spoil disposal site. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0051] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention:

[0052] like Figure 1 As shown, this invention provides a dynamic assessment method for the long-term stability of spoil heaps based on a combined air-ground-room analysis. The specific process is as follows: First, obtain the original ground elevation before construction and the slope top elevation of the spoil heap after construction; then, based on PS-InSAR technology, perform deformation monitoring and analysis of the spoil heap and combine it with in-situ monitoring results to obtain soil density and moisture content, indirectly obtaining the compaction degree of the spoil heap soil; second, establish fitting formulas for the physical property parameters of the spoil heap soil as a function of compaction degree and moisture content; finally, solve for the stability safety factor of the spoil heap based on the strength reduction method.

[0053] like Figure 1 As shown, a dynamic assessment method for the long-term stability of a spoil disposal site based on a combined air-ground-chamber analysis includes the following steps:

[0054] S1. First, obtain the elevation data before and after the construction of the spoil disposal site. Then, perform a double integral based on the elevation difference before and after the spoil disposal site to obtain the initial volume V0 of the spoil disposal site, and then obtain the initial density ρ0 of the soil.

[0055] First, obtain the elevation data before and after the construction of the spoil heap. The original ground elevation before construction is H0(x,y), and the elevation of the top surface of the spoil heap after construction is H. f (x,y) can be integrated to obtain the initial volume V0 of its spoil disposal site. Then, based on the mass m0 after the spoil disposal site is filled, the initial density ρ0 of the soil in the spoil disposal site can be obtained. The relevant formulas are shown below.

[0056]

[0057]

[0058] Where V0 is the initial volume of the spoil heap soil, ρ0 is the initial density of the spoil heap soil, H0(x,y) is the elevation of the original ground before the construction of the spoil heap, and H f (x,y) represents the elevation of the top surface of the spoil heap after completion, and m0 represents the mass of the spoil heap after it is filled.

[0059] S2. Using PS-InSAR technology, the time series of surface deformation of the spoil heap in the study area at different periods are obtained. The surface subsidence is then calculated. Finally, the difference between the elevation value of the spoil heap after completion obtained in step S1 and the surface subsidence is double-integrated to obtain the volume change ΔV of the spoil heap. i This leads to the soil density ρ. i ;

[0060] The PS-InSAR technology was used to obtain the deformation characteristics of spoil heaps in the study area at different times. The software platform used was ENVI, and the software used for data visualization analysis was ArcMap. The processing flow is as follows: Figure 2 As shown. Before conducting PS-InSAR technology analysis on the deformation characteristics of spoil heaps in different periods in the study area, the following preparatory work is required:

[0061] (1) First, it is necessary to download remote sensing satellite images of the spoil disposal sites in different periods of the study area. These images can be downloaded by registering on the Alaska Satellite News Agency website. When downloading remote sensing satellite images, relevant settings need to be made. Generally, image data from the Sentinel-1 satellite should be selected. At the same time, the scope of the spoil disposal sites in the study area should be selected and the time span of the spoil disposal site images should be selected. Generally, the date from the completion date of the spoil disposal site to the current date should be selected. Second, select the data type as SLC / IW mode. Finally, search and download satellite images from different periods.

[0062] (2) Furthermore, in order to analyze the image data of the Sentinel-1 satellite, it is necessary to download the precise orbit file corresponding to the image.

[0063] After completing steps (1) and (2) above, the information is input into ENVI software for PS process inversion analysis. After the analysis is completed, the target deformation data of the spoil heap in the study area can be obtained. Then, the data is imported into ArcMap software for Kriging interpolation analysis to obtain the deformation results of the spoil heap at different times. Finally, based on the deformation results, the settlement and volume change ΔV of the spoil heap site are further calculated. i This leads to the soil density ρ. i The relevant formulas are shown below.

[0064]

[0065]

[0066] Wherein, △V i and ρ i These represent the volume change and soil density of the spoil heap at different times, respectively. V0 is the initial volume of the spoil heap, m0 is the mass of the spoil heap after completion, and H... i(x, y) represents the elevation of the top surface of the spoil heap at different stages of the settling process, H f (x,y) represents the elevation of the top surface of the waste disposal site after completion.

[0067] S3. Obtain the surface displacement and soil moisture content values ​​through the GNSS monitoring station and moisture content sensor deployed in situ.

[0068] Among them, GNSS monitoring stations are set up at different elevations in the spoil heap to verify the accuracy of PS-InSAR inversion results, and moisture content sensors are set up inside the soil of the spoil heap to monitor the moisture content inside the spoil soil.

[0069] S4. The maximum dry density of the soil was obtained based on the indoor soil compaction test. At the same time, the compaction degree of the soil was indirectly obtained based on the soil density obtained in step S2 and the soil moisture content obtained in step S3.

[0070] Among them, the maximum dry density ρ of the soil dmax To obtain the required data, samples with different moisture contents need to be prepared from the waste soil, and indoor compaction tests should be conducted to obtain the curve showing the relationship between the dry density and moisture content of the waste soil. The highest point of the curve represents the maximum dry density ρ of the waste site soil. dmax The moisture content corresponding to the highest point is its optimum moisture content w. opt Simultaneously, based on the soil density ρ obtained in step S2... i The soil moisture content value w obtained in step S3 i The compaction degree λ of the soil is obtained indirectly. i The relevant formulas are shown below.

[0071]

[0072] Where, ρ dmax λ represents the maximum dry density of the soil in the spoil heap. i ρ represents the soil compaction degree of the spoil heap at different times. i For the soil density of the spoil heap at different times, w i The moisture content of the soil in the spoil heap at different times.

[0073] S5. Based on step S4, the maximum dry density and compaction degree of the soil in the spoil heap of the study area were obtained. Indoor triaxial shear tests were conducted on the soil under different moisture contents and different compaction degrees to obtain the physical property parameters of the soil under different moisture contents and different compaction degrees. The physical property parameters of the soil include cohesion, internal friction angle, elastic modulus and Poisson's ratio.

[0074] Among them, the maximum dry density ρ of the spoil soil in the spoil disposal site is obtained according to step S4. dmaxTriaxial specimens with different moisture contents and compaction degrees were prepared. Simultaneously, to analyze the strength parameters of the spoil heap soil under the influence of environmental factors (rainfall, earthquakes, etc.), saturated and unsaturated triaxial shear tests were conducted. To more accurately reflect the shear strength of the spoil heap soil, a shear rate of 1 mm / min was selected for the triaxial shear tests. The test was terminated when the cumulative axial strain of the specimen reached 20%. The above steps were repeated to conduct triaxial shear tests under different confining pressures, obtaining Mohr's stress circles under different confining pressures. Strength envelopes tangent to the Mohr's stress circles were plotted, where the slope and intercept of the strength envelope curve on the ordinate represent the internal friction angle φ of the spoil heap soil, respectively. i and cohesion c i The elastic modulus E of the soil can be obtained from the stress-strain curve of the waste soil. i The Poisson's ratio of the waste soil was calculated indirectly. The Poisson's ratio is related to the soil's coefficient of earth pressure at rest, which in turn is related to its internal friction angle. The relevant formulas are shown below. The Poisson's ratio of the soil can be obtained from these formulas, and the relevant process is as follows: Figure 3 As shown.

[0075]

[0076]

[0077] In the formula: v i For the Poisson's ratio of the soil, K i φ is the coefficient of earth pressure at rest of the soil. i The friction angle within the soil.

[0078] S6. Based on the soil physical property parameters obtained in step S5, including cohesion, internal friction angle, elastic modulus, and Poisson's ratio, perform multiple regression analysis to establish fitting formulas for the soil physical property parameters as a function of water content and compaction degree.

[0079] Based on the relationship between the relevant physical property parameters of the spoil heap soil (cohesion, internal friction angle, elastic modulus, and Poisson's ratio) obtained in step S5 and the changes in compaction degree and moisture content, a multiple regression analysis is performed to obtain the functional relationships between cohesion and compaction degree and moisture content, internal friction angle and compaction degree and moisture content, elastic modulus and compaction degree and moisture content, and Poisson's ratio and compaction degree and moisture content. The relevant formulas are shown below. Based on these established functional relationships, it is only necessary to know the compaction degree and moisture content of the spoil heap site to quickly obtain its corresponding soil physical property parameters. The soil physical property parameters include cohesion, internal friction angle, elastic modulus, and Poisson's ratio, providing the necessary soil physical property parameters for solving the stability of the spoil heap.

[0080]

[0081]

[0082]

[0083]

[0084] Among them, c i φ i E i v i These represent the cohesion, angle of internal friction, elastic modulus, Poisson's ratio, and λ of soil under different moisture contents and compaction degrees. i and w i For the function f(λ) i , w i The independent variable of f(λ) i , w i ) is about λ i and w i The changing functional relationship.

[0085] S7. Soil compaction degree λ obtained in real time through steps S2 and S3. i and moisture content value w i Substituting these parameters into the fitting formula for the changes in soil physical properties with water content and compaction degree in step S6, we obtain the dynamically changing soil physical property parameters, including cohesion c. i internal friction angle φ i Elastic modulus E i Poisson's ratio v i Then, the strength reduction method was used to conduct a stability analysis of the spoil heap, and the dynamic stability safety factor F of the spoil heap was obtained. i ;

[0086] First, before performing stability calculations using the strength reduction method, a three-dimensional numerical model of the spoil disposal site is established based on the site's boundary contour and the boundary between the spoil and the underlying bedrock layer, or a two-dimensional model is established for sections with potential slippage hazards.

[0087] Secondly, such as Figure 4 As shown, based on the soil compaction degree and moisture content values ​​obtained in real time in steps S2 and S3, it should be noted that, taking advantage of the characteristic of InSAR images being captured every 12 days, and based on the capture date, the soil compaction degree and moisture content are detected on the corresponding date. The compaction degree and moisture content information obtained from the on-site detection every 12 days are substituted into the fitting formula for soil physical property parameters versus compaction degree and moisture content in step S6, thus obtaining the soil physical property parameters at different times under environmental influence. The soil physical property parameters at different times include cohesion c.i internal friction angle φ i Elastic modulus E i Poisson's ratio v i These soil physical property parameters are input into finite difference software for strength reduction analysis to obtain the stability safety factor F at different times. i The relevant process is as follows: Figure 4 As shown.

[0088] S8. Using the dynamic stability safety factor of the spoil disposal site obtained in step S7, establish a fitting formula for the stability safety factor of the spoil disposal site as a function of compaction degree and moisture content. The relevant formula is shown below, providing a reliable assessment method for the long-term dynamic stability assessment of the spoil disposal site.

[0089]

[0090] Among them, F i The stability safety factor of the spoil disposal site at different times, i.e., the dynamic stability safety factor, is given by F. i When F > 1, it indicates that the spoil disposal site is relatively safe; when F i When F = 1, it indicates that the spoil disposal site is in a critical state and the possibility of landslide failure is relatively high; when F i When the value is less than 1, it indicates that a landslide has occurred at the spoil disposal site, which is extremely dangerous.

[0091] The above embodiments are only representative of some of the embodiments that can be implemented by the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A method for dynamic evaluation of the long-term stability of spoil heaps based on a combined air-ground-chamber analysis, characterized in that, Includes the following steps: S1. Obtain the elevation data of the spoil disposal site before and after construction. Perform a double integral based on the elevation difference between the two construction periods to obtain the initial volume V0 of the spoil disposal site, and then obtain the initial density ρ0 of the soil. S2. Using PS-InSAR technology, the time series of surface deformation at different periods of the spoil heap in the study area are obtained, and the surface subsidence is calculated. Then, the difference between the elevation value after the completion of the spoil heap obtained in step S1 and the surface subsidence is double integrated to obtain the volume change ΔV of the spoil heap. i Thus, the soil density ρ is obtained. i ; S3. The surface displacement and soil moisture content are obtained by using GNSS monitoring stations and moisture content sensors deployed in situ. S4. The maximum dry density of the soil was obtained based on the indoor soil compaction test. At the same time, the compaction degree of the spoil heap soil was obtained based on the soil density obtained in step S2 and the soil moisture content obtained in step S3. S5. Based on the maximum dry density and compaction degree of the soil in the waste disposal site obtained in step S4, conduct indoor triaxial shear tests on the soil under different moisture contents and different compaction degrees to obtain the soil physical property parameters under different moisture contents and different compaction degrees. The soil physical property parameters include cohesion, internal friction angle, elastic modulus, and Poisson's ratio. S6. Based on the soil physical property parameters obtained in step S5, perform multiple regression analysis to establish fitting formulas for the soil physical property parameters as a function of water content and compaction degree. S7. The soil compaction degree and moisture content obtained in real time through steps S4 and S3 are substituted into the fitting formula of the soil physical property parameters as a function of moisture content and compaction degree in step S6 to obtain the dynamically changing soil physical property parameters. The dynamically changing soil physical property parameters include cohesion, internal friction angle, elastic modulus and Poisson's ratio. Then, the strength reduction method is used to perform stability analysis of the spoil heap to obtain the dynamic stability safety factor of the spoil heap. S8. Using the dynamic stability safety factor of the spoil disposal site obtained in step S7, perform multiple regression analysis to establish a fitting formula for the dynamic stability safety factor of the spoil disposal site as a function of compaction degree and moisture content, thereby dynamically assessing the long-term stability of the spoil disposal site in the future.

2. The method for dynamic evaluation of long-term stability of spoil disposal sites based on combined air-ground-chamber analysis according to claim 1, characterized in that, Step S1 specifically involves: The elevation H0(x,y) of the original ground surface before the construction of the spoil disposal site in the study area was obtained, and the elevation H of the top surface of the spoil disposal site after construction was obtained. f (x,y), the initial volume V0 and initial density ρ0 of the spoil disposal site soil are obtained according to the following formula; Where V0 is the initial volume of the spoil heap soil, ρ0 is the initial density of the spoil heap soil, H0(x,y) is the elevation of the original ground before the construction of the spoil heap, and H f (x,y) represents the elevation of the top surface of the spoil heap after completion, and m0 represents the mass of the spoil heap after it is filled.

3. The method for dynamic evaluation of long-term stability of spoil disposal sites based on combined air-ground-chamber analysis according to claim 1, characterized in that, Step S2 specifically involves: First, the geographical location of the spoil heap in the study area was determined. Then, satellite data of the spoil heap at different times was downloaded from the official satellite data website. Next, remote sensing image processing software was used to process and analyze the satellite images to obtain deformation characteristic points of the spoil heap at different times. Further, Kriging interpolation analysis was performed on the processed deformation characteristic points to obtain the deformation results of the study area. Finally, the elevation H of the spoil heap's top surface at different times during the settlement process was calculated using the obtained deformation results. i (x, y), and then the volume change ΔV of the spoil heap at different times is obtained by the following formula. i and soil density ρ i ; Wherein, △V i and ρ i These represent the volume change and soil density of the spoil heap at different times, respectively. V0 is the initial volume of the spoil heap, m0 is the mass of the spoil heap after completion, and H... i (x, y) represents the elevation of the top surface of the spoil heap at different stages of the settling process, H f (x,y) represents the elevation of the top surface of the waste disposal site after completion.

4. The method for dynamic evaluation of long-term stability of spoil heaps based on combined air-ground-chamber analysis according to claim 1, characterized in that, Step S4 specifically involves: The maximum dry density ρ of the soil was obtained based on indoor soil compaction tests. dmax Simultaneously, based on the soil density ρ of the spoil heap at different times obtained in step S2... i The soil moisture content w at different times of the spoil heap obtained in step S3 i The value can be substituted into the following formula to obtain the soil compaction degree λ of the spoil heap at different times. i , Where, ρ dmax λ represents the maximum dry density of the soil in the spoil heap. i ρ represents the soil compaction degree of the spoil heap at different times. i For the soil density of the spoil heap at different times, w i The moisture content of the soil in the spoil heap at different times.

5. The method for dynamic evaluation of long-term stability of spoil heaps based on combined air-ground-chamber analysis according to claim 1, characterized in that, Step S5 specifically involves: Based on the maximum dry density and compaction degree of the soil in the spoil heap obtained in step S4, indoor triaxial shear tests were conducted on the soil under different moisture contents and compaction degrees. The specific steps of the triaxial shear test are as follows: First, cylindrical soil samples with different compaction degrees and moisture contents were prepared; then, the samples were fitted with a rubber diaphragm and installed in the pressure chamber of the triaxial shear test apparatus; next, the pressure chamber was filled with water, and the soil samples were subjected to saturation or unsaturation operations, as well as different confining pressures. A consolidation-drained test was used to conduct the shear test at a shear rate of 1 mm / min until the axial strain of the sample reached 20%, at which point loading was stopped; finally, the physical property parameters of the spoil heap soil under different moisture contents and compaction degrees were analyzed, including cohesion c. i internal friction angle φ i Elastic modulus E i Poisson's ratio v i .

6. The method for dynamic evaluation of long-term stability of spoil disposal sites based on combined air-ground-chamber analysis according to claim 1, characterized in that, Step S6 specifically involves: Based on step S5, the physical property parameters of the waste soil under different moisture contents and different compaction conditions, including cohesion c, were obtained. i internal friction angle φ i Elastic modulus E i Poisson's ratio v i Perform multiple regression analysis and select the coefficient of determination R. 2 The fitting formula closest to 1 can be used to obtain the fitting formula for the changes of soil physical properties with compaction degree and water content. The functional expressions of the relevant formulas are shown below. Where, λ i To determine the soil compaction degree of the spoil heap at different times, w i c represents the soil moisture content at different times in the spoil heap. i φ i E i v i These represent the cohesion, internal friction angle, elastic modulus, Poisson's ratio, and λ of soil under different moisture contents and compaction degrees. i and w i For the function f(λ) i , w i The independent variable of f(λ) i , w i ) is about λ i and w i The changing functional relationship.

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