Reservoir landslide instability prediction method and device
By establishing a normal stress and rate dependence model of the residual friction coefficient of the slip zone soil, and combining it with pore water pressure and hydrodynamic effects, a dynamic model was constructed, which solved the problem of accuracy in landslide instability risk assessment and velocity prediction, and realized the explanation of landslide instability mechanism and support for disaster prevention work.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-08
- Publication Date
- 2026-03-17
AI Technical Summary
Existing technologies cannot accurately characterize the variation of the residual friction coefficient of the slip zone soil and ignore the influence of unsaturated effects on landslide movement, resulting in insufficient accuracy in landslide instability risk assessment and velocity prediction.
By establishing normal stress-dependent and rate-dependent models of the residual friction coefficient of the slip zone soil, and combining pore water pressure and hydrodynamic effects under a three-dimensional framework, a dynamic model is constructed to calculate the landslide acceleration and velocity.
It improves the accuracy of judging the probability of landslide instability and the precision of predicting instability speed, and explains the movement mechanism of landslides from slow creep to rapid instability.
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Figure CN121683239A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of geological disaster prediction technology, and in particular to a method and apparatus for predicting landslide instability in reservoir areas. Background Technology
[0002] Numerous studies have shown that the slow creep of landslides can last for months or even years, with deformation rates spanning multiple orders of magnitude from creep to accelerated instability, ranging from mm / year to m / s. Under certain triggering factors, these rates can suddenly accelerate and cause catastrophic instability. The slip zone soil is crucial in controlling landslide evolution and its capacity for instability, and its residual friction coefficient dynamically changes in real time with the landslide's deformation rate and the overlying normal stress. This means that the slip zone soil at different locations and depths within the landslide mass will have different residual friction coefficients. However, existing studies on landslide velocity prediction often use a constant friction coefficient for the slip zone soil, failing to accurately characterize the variation of the residual friction coefficient and neglecting the intrinsic mechanisms influencing landslide instability, thus making it difficult to obtain velocity predictions that accurately reflect the actual landslide conditions.
[0003] In addition, the low shear strength of the slip zone soil and changes in pore water pressure have long been considered major factors contributing to landslide instability and rapid movement. Therefore, it is reasonable to reveal abrupt changes in landslide velocity by describing the changes in pore water pressure within the slip zone soil area. However, existing studies often assume that the slip zone is in a saturated and dry state and simplify it to hydrostatic pressure, failing to distinguish between steady-state hydrostatic pressure and transient excess pore water pressure. They often neglect the influence of unsaturation on the strength of the slip zone soil and fail to fully quantify the feedback of pore water pressure in the unsaturated zone and the stress disturbances caused by rainfall or sudden changes in reservoir water level, resulting in insufficient accuracy in predicting landslide velocity.
[0004] Due to the aforementioned limitations, it is currently difficult to clearly define the specific critical conditions under which a landslide transitions from isokinetic creep to accelerated instability, thus affecting the accuracy of instability risk assessment and velocity prediction. For landslides that have undergone long-term creep, traditional methods cannot accurately determine whether they possess the ability to move rapidly, nor can they accurately predict the velocity after instability. Therefore, developing a dynamic model and method that can accurately characterize the dual mechanical properties of the slip zone soil and comprehensively consider multiple fields such as pore water pressure and hydrodynamics within a three-dimensional framework is crucial for improving the accuracy of landslide instability probability assessment and achieving precise prediction of landslide instability velocity. Summary of the Invention
[0005] The purpose of this invention is to provide a method and apparatus for predicting landslide instability in reservoir areas, which can accurately predict the possibility of landslide instability and improve the accuracy of landslide instability velocity.
[0006] To address the above problems, a first aspect of the present invention provides a method for predicting landslide instability in reservoir areas, comprising the following steps: Step S1: Obtain the porosity, cohesion, and density of the sliding soil at the sliding zone depth of the target landslide. Step S2: Obtain and establish a normal stress dependence model and a rate dependence model of the residual friction coefficient of the slip zone soil based on the slip body density and the rate dependence data of the residual friction coefficient of the slip zone soil. Step S3: Couple the normal stress dependence model and the rate dependence model of the residual friction coefficient of the slip zone soil to obtain a joint model; Step S4: Discretize the target landslide into several columns, calculate the self-weight stress, hydrostatic pressure, excess pore water pressure, water resistance, buoyancy force, and frictional resistance along the sliding surface of each column, and obtain the cohesion of the sliding zone soil from step S1, thereby listing the dynamic equilibrium equation for each column, and solving the dynamic equilibrium equation to obtain the landslide acceleration of each column. Step S5: Take the instant when the target landslide begins to slide down sharply as the initial time point, and calculate the motion state of each of the column bodies in the initial state. The motion state includes: the self-weight stress, the hydrostatic pressure, the excess pore water pressure, the water resistance, the buoyancy force, and the frictional resistance of the column body along the sliding surface. Step S6: Iteratively calculate the motion state of each of the columns, and calculate the landslide acceleration and motion velocity of each column at each moment.
[0007] Furthermore, step S1 in the above-mentioned method for predicting landslide instability in reservoir areas includes: Step S11: Collect soil samples of the slip zone soil at the depth of the slip zone of the target landslide; Step S12: Determine the porosity of the slip zone soil, the cohesion of the slip zone soil, and the density of the slip body in the soil sample.
[0008] Furthermore, step S2 in the above-mentioned method for predicting landslide instability in reservoir areas includes the following steps: Step S21: Perform a single-stage shear test on the soil sample using different normal stresses and a fixed shear rate, and determine the residual friction coefficient of the slip zone soil and the density of the slip body. Step S22: Establish an empirical relationship between the residual friction coefficient of the slip zone soil and the density of the slip body, and establish a normal stress dependence model for the residual friction coefficient of the slip zone soil; The specific relation is as follows: (1) in, This is the normal stress correction factor. For the normal stress, The normal stress fitting parameters are those described in the first description. The normal stress fitting parameters are those described in the second description. The normal stress fitting parameters are those described in the third paragraph; Step S23: The soil sample is subjected to continuous shearing with a fixed normal stress and a shear rate that gradually increases from slow to fast, and the rate dependence data of the residual friction coefficient of the slip zone soil is measured. Step S24: Based on the rate dependence data of the residual friction coefficient of the slip zone soil, an empirical formula is obtained by fitting, and a rate dependence model of the residual friction coefficient of the slip zone soil is established. The specific relation is as follows: Rate weakening stage: The residual friction coefficient decreases logarithmically with increasing shear rate, as shown in the following equation: (2) Rate-enhancing stage: The residual friction coefficient increases exponentially with the shear rate, as shown in the following formula: (3) Neutral effect: The residual friction coefficient does not change with the shear rate and exhibits a linear relationship. (4) in, To account for the dynamic residual friction coefficient that varies with the shear rate, The shear rate, The parameters are the fitting parameters for the first rate. The second rate fitting parameter, The third rate fitting parameter, The fourth rate fitting parameter, The fifth rate fitting parameter, The sixth rate fitting parameter.
[0009] Furthermore, the calculation formula for the joint model in step S3 of the above-mentioned landslide instability prediction method for reservoir areas is as follows: (5) in, The dynamic residual friction coefficient is... The normal stress correction factor is... The dynamic residual friction coefficient is taken into account the change in shear rate.
[0010] Furthermore, step S4 in the above-mentioned method for predicting landslide instability in reservoir areas includes the following steps: Step S41: Discretize the target landslide into several of the aforementioned columnar sections, dividing them into... OK List; Step S42: Calculate the first... OK The self-weight stress of the column of the column ; The specific calculation formula is as follows: (6) in, The density of the sliding body, It is the acceleration due to gravity. For the first OK The volume of the columnar bars; Step S43: Calculate the first... OK The hydrostatic pressure of the column of bars ; The specific calculation formula is as follows: (7) in, The water weight is [unclear]. For the first OK The height of the groundwater level of the column mentioned above, For the first OK The width of the column bars in the column; Step S44: Calculate the first... OK The excess pore water pressure of the columnar bars ; Step S45: Calculate the first... OK The water resistance of the column of bars ; Step S45 includes: Step S451: Calculate the first... OK The water resistance experienced by the columnar sections; The specific calculation formula is as follows: (twenty one) in, The empirical drag coefficient is usually taken as... , For the first OK The water-facing area of the columnar sections; Step S46: Calculate the buoyancy force exerted on the column by the water. OK The buoyancy of the columnar bars ; The specific calculation formula is as follows: (twenty two) in, For the first OK The volume of the portion of the column submerged in water; Step S47: Calculate the first shear rate and the normal stress based on the shear rate and the normal stress. OK The frictional resistance of the column along the sliding surface; The specific calculation formula is as follows: (twenty three) in, This is the normal reaction force acting on the sliding surface; Step S48: Based on the cohesion of the slip zone soil obtained in step S1, measure the cementing force between soil particles; Step S49: Construct the first OK The dynamic equilibrium equations of the columnar bars, The dynamic balance equation is: (twenty four) (25) in, For the first OK The angle between the columnar bars and the xoy plane; By summing the values of all the aforementioned columns, the equation for the landslide acceleration is obtained. Specifically, the equation is to be solved as follows: (26) in, Set as the dynamic calculation coefficient, .
[0011] Furthermore, step S44 in the above-mentioned reservoir area landslide instability prediction method includes: Step S441: Based on the fact that the pore water pressure in the saturated soil of the slip zone is equivalent to the stress in the soil, calculate the first... OK The shear stress of the columnar bar and normal stress ; No. OK The shear stress of the column of the column The formula for calculation is: (8) in, For the first OK The inclination angle of the sliding surface of the column. The length of the column; No. OK The normal stress of the column of the column The formula for calculation is: (9) Step S442: Place the first OK The shear stress of the column of the column and the normal stress By converting the slip surface stress to plane stress, we obtain: (10) (11) in, For the first OK The maximum principal stress of the column in the column, For the first OK The minimum principal stress of the column column; Step S443: Based on the fact that the pore water pressure caused by the load change is caused by the average increase in normal stress and the increase in shear stress, calculate the relationship between the volumetric deformation and stress of the soil. The specific relation is as follows: (12) in, This represents the volumetric strain within the soil skeleton. V The initial total volume of the soil before it is subjected to force. This refers to the volume change of the soil mass after it is subjected to force. For the effective octahedral normal stress increment, This represents the increment of octahedral shear stress. The bulk modulus of deformation, Shear dilatation modulus; Step S444: Next, calculate the relationship between the volumetric deformation and stress of the soil pores; The specific relation is as follows: (13) The deformation is the pore volume deformation per unit soil mass. The change in pore volume of the soil is expressed as a unit. The volume compressibility coefficient of the medium in the pores. The porosity of the soil is given. This represents the increase in pore water pressure without drainage. Step S445: According to the principles of soil mechanics, soil particles do not deform under low or high stress conditions. Therefore, the volumetric strain in the soil skeleton is equal to the pore volume deformation per unit soil volume. Based on the principle of effective stress, the effective octahedral normal stress increment is calculated. : (14) in, The total normal stress of the octahedron. This is the increment of the pore water pressure; Step S446: When the soil is saturated, the water cannot be compressed. The pore water pressure increment is calculated. The specific calculation formula is as follows: (15) Rewrite formula (15) as an expression containing stress components: (16) in, The maximum principal stress, The intermediate principal stress, The minimum principal stress is, and ; Step S447: According to soil mechanics theory, under undrained conditions, the lateral pressure on the soil is the same and zero. Therefore... And since the initial pore water pressure is 0, the pore water pressure of the saturated soil is: (17) in, For material constants, ; Step S448: Calculate the first... OK The pore water pressure of the columnar bars for: (18) Rewriting formula (18) yields: (19) Therefore, the calculation yields the [number]. OK The excess pore water pressure of the columnar bars ; The specific calculation formula is as follows: (20) Furthermore, step S6 in the above-mentioned method for predicting landslide instability in reservoir areas includes the following steps: Step S61: Calculate the initial landslide acceleration and velocity of each column based on its initial motion state; Step S62: Iteratively calculate the motion state of each of the columns at each time step. Based on the initial acceleration and velocity of each column and the motion state at each time step, calculate the landslide acceleration of each column at each time step, and then obtain the velocity of each column at each time step, until the velocity is 0, then stop the calculation.
[0012] According to another aspect of the present invention, a reservoir landslide instability prediction device is provided, comprising the following modules: Data acquisition module: used to acquire the porosity, cohesion, and density of the sliding soil at the sliding zone depth of the target landslide. Friction Model Module: Used to acquire and establish the normal stress dependence model and the rate dependence model of the residual friction coefficient of the slip zone soil based on the slip body density and the rate dependence data of the residual friction coefficient of the slip zone soil. Fusion model module: used to couple the normal stress dependence model and the rate dependence model of the residual friction coefficient of the slip zone soil to obtain a joint model; Acceleration calculation module: used to discretize the target landslide into several columns, calculate the self-weight stress, hydrostatic pressure, excess pore water pressure, water resistance, buoyancy force, and frictional resistance along the sliding surface of each column, obtain the cohesion of the sliding zone soil from step S1, measure the cementing force between soil particles, and thus list the dynamic equilibrium equations for each column. Solving the dynamic equilibrium equations yields the landslide acceleration for each column. Motion state calculation module: used to take the instant when the target landslide begins to slide down sharply as the initial time point, and calculate the motion state of each of the column bodies in the initial state. The motion state includes: the self-weight stress, the hydrostatic pressure, the excess pore water pressure, the water resistance, the buoyancy force, and the frictional resistance of the column body along the sliding surface. Prediction module: used to iteratively calculate the motion state of each of the pillars, and calculate the landslide acceleration and velocity of each of the pillars at each moment.
[0013] The above-mentioned technical solution of the present invention has the following beneficial technical effects: First, the friction coefficient under different normal stresses and shear rates is experimentally measured, making the friction coefficient of the target landslide during sliding more closely resemble the actual situation. Then, the target landslide is discretized into several columns. Next, the dynamic equilibrium equations of the columns are listed and solved to obtain the landslide acceleration of the columns. Then, the instant when the target landslide begins to slide rapidly is taken as the initial time point. Based on the previous experimental data, the friction coefficient is dynamically obtained during calculation, making the landslide acceleration and velocity of the columns at each moment closer to the actual situation, until the velocity reaches 0, at which point the calculation stops. This method effectively explains the movement mechanism of landslides from slow creep to rapid instability, improves the accuracy of the velocity during landslide instability, and provides assistance for landslide disaster prevention work. Attached Figure Description
[0014] Figure 1 This is a flowchart of the steps according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the target landslide segmentation according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the force analysis of the column body according to an embodiment of the present invention; Figure 4 This is a structural block diagram according to an embodiment of the present invention. Detailed Implementation
[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.
[0016] refer to Figure 1 The present invention describes a method for predicting landslide instability in reservoir areas, including: Step S1: Obtain the porosity, cohesion, and density of the sliding soil at the sliding zone depth of the target landslide. Specifically, step S1 includes: Step S11: Collect soil samples of the slip zone soil at the depth of the slip zone of the target landslide; Step S12: Determine the porosity of the slip zone soil, the cohesion of the slip zone soil, and the density of the slip body in the soil sample; Step S2: Obtain and establish the normal stress dependence model and the rate dependence model of the residual friction coefficient of the slip zone soil based on the sliding body density and the rate dependence data of the residual friction coefficient of the slip zone soil. Specifically, step S2 includes the following steps: Step S21: Perform a single-stage shear test on the soil sample using different normal stresses and a fixed shear rate, and determine the residual friction coefficient of the slip zone soil and the density of the slip body. Step S22: Establish an empirical relationship between the residual friction coefficient of the slip zone soil and the density of the slip body, and establish a normal stress dependence model for the residual friction coefficient of the slip zone soil; The specific relation is as follows: (1) in, This is the normal stress correction factor. For the normal stress, The normal stress fitting parameters are those described in the first description. The normal stress fitting parameters are those described in the second description. The normal stress fitting parameters are those described in the third section.
[0017] Step S23: The soil sample is subjected to continuous shearing with a fixed normal stress and a shear rate that gradually increases from slow to fast, and the rate dependence data of the residual friction coefficient of the slip zone soil is measured. Step S24: Plot the normalized shear rate variation curve based on the rate dependence data of the residual friction coefficient of the slip zone soil, fit the empirical formula, and establish the rate dependence model of the residual friction coefficient of the slip zone soil. The specific relation is as follows: Rate weakening stage: The residual friction coefficient decreases logarithmically with increasing shear rate, as shown in the following formula: (2) Rate-enhancing stage: The residual friction coefficient increases exponentially with the shear rate, as shown in the following formula: (3) Neutral effect: The residual friction coefficient does not change with the shear rate and exhibits a linear relationship. (4) in, To account for the dynamic residual friction coefficient that varies with the shear rate, The shear rate, The parameters are the fitting parameters for the first rate. The second rate fitting parameter, The third rate fitting parameter, The fourth rate fitting parameter, The fifth rate fitting parameter, The parameters are for fitting the sixth rate; Step S3: Couple the normal stress dependence model and the rate dependence model of the residual friction coefficient of the slip zone soil to obtain a joint model; Specifically, the calculation formula is: (5) in, The dynamic residual friction coefficient is... The normal stress correction factor is... The dynamic residual friction coefficient taking into account the change in shear rate; Step S4: Discretize the target landslide into several columns, calculate the self-weight stress, hydrostatic pressure, excess pore water pressure, water resistance, buoyancy force, and frictional resistance along the sliding surface of each column, and obtain the cohesion of the slip zone soil from step S1, thereby listing the dynamic equilibrium equation for each column, and solving the dynamic equilibrium equation to obtain the landslide acceleration of each column. Step S4 includes the following steps: Step S41: Discretize the target landslide into several of the aforementioned columnar sections, dividing them into... OK List; Step S42: Calculate the first... OK The self-weight stress of the column of the column ; The specific calculation formula is as follows: (6) in, The density of the sliding body, It is the acceleration due to gravity. For the first OK The volume of the columnar bars; Step S43: Calculate the first... OK The hydrostatic pressure of the column of bars ; The specific calculation formula is as follows: (7) in, The water weight is [unclear]. For the first OK The height of the groundwater level of the column mentioned above, For the first OK The width of the column bars in the column; Step S44: Calculate the first... OK The excess pore water pressure of the columnar bars ; Step S44 includes: Step S441: Based on the fact that the pore water pressure in the saturated soil of the slip zone is equivalent to the stress in the soil, calculate the first... OK The shear stress of the columnar bar and normal stress ; No. OK The shear stress of the column of the column The formula for calculation is: (8) in, For the first OK The inclination angle of the sliding surface of the column is as follows. The length of the column; No. OK The normal stress of the column of the column The formula for calculation is: (9) Step S442: Place the first OK The shear stress of the column of the column and the normal stress By converting the slip surface stress to plane stress, we obtain: (10) (11) in, For the first OK The maximum principal stress of the column in the column, For the first OK The minimum principal stress of the column column; Step S443: Based on the fact that the pore water pressure caused by the load change is caused by the average increase in normal stress and the increase in shear stress, calculate the relationship between the volumetric deformation and stress of the soil. The specific relation is as follows: (12) in, Let be the volumetric strain in the soil skeleton. V The initial total volume of the soil before it is subjected to force. This refers to the volume change of the soil mass after it is subjected to force. For the effective octahedral normal stress increment, This is the increment of the shear stress of the octahedron. The bulk modulus of deformation is... The shear dilatation modulus; Step S444: Next, calculate the relationship between the volumetric deformation and stress of the soil pores; The specific relation is as follows: (13) The deformation is the pore volume deformation per unit soil mass. The change in pore volume of the soil is expressed as a unit. The volume compressibility coefficient of the medium in the pores is given. The porosity of the soil is given. The pore water pressure increment under non-drainage conditions; Step S445: According to the principles of soil mechanics, soil particles do not deform under low or high stress conditions. Therefore, the volumetric strain in the soil skeleton is equal to the pore volume deformation per unit soil volume. Based on the principle of effective stress, the effective octahedral normal stress increment is calculated. : (14) in, The total normal stress of the octahedron is given. This is the increment of the pore water pressure; Step S446: When the soil is saturated, the water cannot be compressed. The pore water pressure increment is calculated. The specific calculation formula is as follows: (15) Rewrite formula (15) as an expression containing stress components: (16) in, The maximum principal stress, The intermediate principal stress, The minimum principal stress is, and ; Step S447: According to soil mechanics theory, under undrained conditions, the lateral pressure on the soil is the same and zero. Therefore... And since the initial pore water pressure is 0, the pore water pressure of the saturated soil is: (17) in, For material constants, ; Step S448: Calculate the first... OK The pore water pressure of the columnar bars for: (18) Rewriting formula (18) yields: (19) Therefore, the calculation yields the [number]. OK The excess pore water pressure of the columnar bars ; The specific calculation formula is as follows: (20) Step S45: Calculate the first... OK The water resistance of the column of bars ; Step S45 includes: Step S451: Calculate the first... OK The water resistance experienced by the columnar sections; The specific calculation formula is as follows: (twenty one) in, The empirical drag coefficient is usually taken as... , For the first OK The water-facing area of the columnar sections; Step S46: Calculate the first... based on the buoyancy force exerted on the column by the water... OK The buoyancy of the columnar bars ; The specific calculation formula is as follows: (twenty two) in, For the first OK The volume of the portion of the column submerged in water; Step S47: Calculate the first shear rate and the normal stress based on the shear rate and the normal stress. OK The frictional resistance of the column along the sliding surface; The specific calculation formula is as follows: (twenty three) in, This is the normal reaction force acting on the sliding surface; Step S48: Based on the cohesion of the slip zone soil obtained in step S1, measure the cementing force between soil particles; Step S49: Construct the first OK The dynamic equilibrium equations of the columnar bars, The dynamic balance equation is: (twenty four) (25) in, For the first OK The angle between the columnar bars and the xoy plane; By summing the values of all the aforementioned columns, the equation for the landslide acceleration is obtained. Specifically, the equation is to be solved as follows: (26) in, Set as the dynamic calculation coefficient, ; Step S5: Take the instant when the target landslide begins to slide rapidly as the initial time point, and calculate the motion state of each column in the initial state. The motion state includes: the self-weight stress, the hydrostatic pressure, the excess pore water pressure, the water resistance, the buoyancy force, and the frictional resistance of the column along the sliding surface. Step S6: Iteratively calculate the motion state of each of the columns, and calculate the landslide acceleration and motion velocity of each column at each moment; Specifically, step S6 includes the following steps: Step S61: Calculate the initial landslide acceleration and velocity of each column based on its initial motion state; Step S62: Iteratively calculate the motion state of each of the columns at each time step. Based on the initial acceleration and velocity of each column and the motion state at each time step, calculate the landslide acceleration of each column at each time step, and then obtain the velocity of each column at each time step, until the velocity is 0, then stop the calculation.
[0018] In this embodiment of the invention, the friction coefficient under different normal stresses and shear rates is first measured experimentally to make the friction coefficient of the target landslide more closely reflect the actual situation. Then, the target landslide is discretized into several cylindrical segments. Next, the dynamic equilibrium equations for each cylindrical segment are listed and solved to obtain the landslide acceleration. The instant the target landslide begins its rapid downward slide is taken as the initial time point. Based on the preceding experimental data, the friction coefficient is dynamically acquired during calculation, ensuring that the landslide acceleration and velocity of each cylindrical segment at each moment are closer to the actual situation. Calculation stops when the velocity reaches zero. This method effectively explains the movement mechanism of landslides from slow creep to rapid instability, improves the accuracy of the velocity during landslide instability, and provides assistance for landslide disaster prevention work.
[0019] refer to Figure 4 According to another aspect of the present invention, a reservoir landslide instability prediction device is provided, comprising the following modules: Data acquisition module: used to acquire the porosity, cohesion, and density of the sliding soil at the sliding zone depth of the target landslide. Friction Model Module: Used to acquire and establish the normal stress dependence model and the rate dependence model of the residual friction coefficient of the slip zone soil based on the slip body density and the rate dependence data of the residual friction coefficient of the slip zone soil. Fusion model module: used to couple the normal stress dependence model and the rate dependence model of the residual friction coefficient of the slip zone soil to obtain a joint model; Acceleration calculation module: used to discretize the target landslide into several columns, calculate the self-weight stress, hydrostatic pressure, excess pore water pressure, water resistance, buoyancy force, and frictional resistance along the sliding surface of each column, and obtain the cohesion of the sliding zone soil from step S1, thereby listing the dynamic equilibrium equation of each column, and solving the dynamic equilibrium equation to obtain the landslide acceleration of each column; Motion state calculation module: used to take the instant when the target landslide begins to slide down sharply as the initial time point, and calculate the motion state of each of the column bodies in the initial state. The motion state includes: the self-weight stress, the hydrostatic pressure, the excess pore water pressure, the water resistance, the buoyancy force, and the frictional resistance of the column body along the sliding surface. Prediction module: used to iteratively calculate the motion state of each of the pillars, and calculate the landslide acceleration and velocity of each of the pillars at each moment.
[0020] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.
Claims
1. A method for predicting the instability of a reservoir landslide, characterized in that, The method comprises the following steps: Step S1: obtaining the slide zone soil porosity, the slide zone soil cohesion, and the slide body density of the slide zone soil at the depth of the slide zone of the target landslide; Step S2: obtaining and establishing a normal stress dependence model of the slide zone soil residual friction coefficient and a rate dependence model of the slide zone soil residual friction coefficient according to the slide body density and the rate dependence data of the slide zone soil residual friction coefficient; Step S3: coupling the normal stress dependence model of the slide zone soil residual friction coefficient and the rate dependence model of the slide zone soil residual friction coefficient to obtain a joint model; Step S4: discretizing the target landslide into a plurality of columns, calculating the self-weight stress, the hydrostatic pressure, the excess pore water pressure, the water resistance, the buoyant force, and the frictional resistance of the column along the sliding surface of each column, obtaining the cohesion of the slide zone soil from step S1, determining the cementation force between soil particles, and thus listing the dynamic equilibrium equation of each column, and solving the dynamic equilibrium equation to obtain the landslide acceleration of each column; Step S5: taking the moment when the target landslide starts to slide sharply as the initial time point, and calculating the motion state of each column in the initial state, which includes the self-weight stress, the hydrostatic pressure, the excess pore water pressure, the water resistance, the buoyant force, and the frictional resistance of the column along the sliding surface; Step S6: iteratively calculating the motion state of each column to calculate the landslide acceleration and motion speed of each column at each time.
2. The landslide instability prediction method of the reservoir area according to claim 1, characterized in that: Step S1 comprises: Step S11: collecting the soil sample of the slide zone soil at the depth of the slide zone of the target landslide; Step S12: measuring the slide zone soil porosity, the slide zone soil cohesion, and the slide body density of the soil sample.
3. The landslide instability prediction method of the reservoir area according to claim 2, characterized in that: Step S2 comprises the following steps: Step S21: performing a single-stage shear test on the soil sample by using different normal stresses and a fixed shear rate to measure the slide body density of the slide zone soil residual friction coefficient; Step S22: fitting the slide body density of the slide zone soil residual friction coefficient to establish an empirical relationship and establish the normal stress dependence model of the slide zone soil residual friction coefficient; The specific relationship is: （1） wherein, is a normal stress correction coefficient, is the normal stress, is a first normal stress fitting parameter, is a second normal stress fitting parameter, is a third normal stress fitting parameter; Step S23: performing a continuous shear test on the soil sample by using a fixed normal stress and gradually increasing the shear rate from slow to fast to measure the rate dependence data of the slide zone soil residual friction coefficient; Step S24: fitting the rate dependence data of the slide zone soil residual friction coefficient to obtain an empirical formula and establish the rate dependence model of the slide zone soil residual friction coefficient; The specific relationship is: In the rate weakening stage, the residual friction coefficient decreases logarithmically with the increase of the shear rate, and the relationship is: （2） Rate strengthening stage: the residual friction coefficient increases exponentially with the increase of the shear rate, and the relationship is: （3） Neutral effect: the residual friction coefficient does not change with the shear rate, and the relationship is linear, （4） wherein, is a dynamic residual friction coefficient accounting for the change in shear rate, is the shear rate, is a first rate fitting parameter, is a second rate fitting parameter, is a third rate fitting parameter, is a fourth rate fitting parameter, is a fifth rate fitting parameter, is a sixth rate fitting parameter.
4. The reservoir landslide instability prediction method according to claim 3, characterized in that: The calculation formula of the joint model in step S3 is: （5） wherein, is the dynamic residual friction coefficient, is the normal stress correction coefficient, is the dynamic residual friction coefficient taking into account the shear rate variation.
5. The reservoir landslide instability prediction method according to claim 4, characterized in that: The step S4 comprises the following steps: Step S41: discretize the target landslide into a plurality of said columnar bodies, into rows columns; Step S42: calculating the self-weight stress of the column body of the row row column ; The specific calculation formula is: （6） wherein, is the density of the slide, is the acceleration of gravity, is the first row column of the volume of the strip body; Step S43: calculating the hydrostatic pressure of the column body of the row row column ; The specific calculation formula is: （7） wherein, is the water body density, is the first row column of the strip post's water table line height, is the first row column of the strip post's width; Step S44: calculating the excess pore water pressure of the column body of the row row column ; Step S45: calculating the water resistance of the column body of the column in the i-th row and j-th column Row Column ; Step S45 comprises: Step S451: calculating the water resistance of the column body of the row line column The specific calculation formula is: （21） wherein is an empirical drag coefficient, typically taken as , is the first row column of the said column body Step S46: calculating the buoyancy of the column of bars according to the buoyancy of the water body row column of bars ; The specific calculation formula is: （22） wherein, is the first row volume of the portion of the column immersed in water; Step S47: calculating a first row column of the pillar bodies along the sliding surface from the shear rate and the normal stress; The specific calculation formula is: （23） wherein is the normal reaction force acting on the sliding surface; Step S48: According to the cohesion of the sliding zone soil obtained in step S1, the cementation force between soil particles is determined. Step S49: constructing the dynamic equilibrium equation of the column body of the column row column The dynamic balance equation is: （24） （25） wherein is the row angle between the column and the xoy plane; The acceleration equation of the landslide is obtained by summing all the column bodies; Specifically, the solving equation is: （26） wherein is set to a power calculation coefficient, .
6. The reservoir landslide instability prediction method according to claim 5, characterized in that: Step S44 comprises: Step S441 : calculating the first stress component of the strip column from the fact that the pore water pressure in the saturated soil mass of the slip zone is equivalent to the stress in the soil mass Row Column and the normal stress ; The shear stress of the column body of the row The shear stress of the column body of the row The shear stress of the column body of the row The calculation formula is: （8） wherein, is the row column of the sliding surface of the strip body, is the length of the strip body; The Row The normal stress of the column body of the column The calculation formula is: （9） Step S442: the shear stress row column of the column body is equivalent to the plane stress from the slip surface stress, and the normal stress and the normal stress is obtained: （10） （11） in, For the first OK The maximum principal stress of the column in the column, For the first OK The minimum principal stress of the column column; Step S443: According to the fact that the pore water pressure caused by the change of load is caused by the average normal stress increment and the shear stress increment, the relationship between the volume deformation of the soil body and the stress is calculated. The specific relationship is: （12） wherein, is the volumetric strain in the soil skeleton, V is the initial total volume of the soil before the stress is applied, is the amount of volume change that occurs in the soil after the stress is applied, is the effective octahedral normal stress increment, is the octahedral shear stress increment, is the bulk modulus of deformation, is the shear dilatancy modulus; Step S444: Then the relationship between the pore volume deformation of the soil body and the stress is calculated. The specific relationship is: （13） is the volumetric deformation of the unit soil mass, is the volumetric change of the unit soil mass, is the volumetric compressibility of the pore medium, is the porosity of the soil mass, is the increment of pore water pressure under undrained conditions; Step S445: According to the principle of soil mechanics, under low stress or higher stress conditions, the soil particles do not deform, so the volume strain in the soil skeleton is equal to the pore volume deformation of the unit soil body. According to the principle of effective stress, the effective octahedral normal stress increment is calculated : （14） wherein, is the octahedral total normal stress, is the increment of the pore water pressure; Step S446: When the soil is saturated, the water body cannot be compressed at this time, take , the increment of the pore water pressure is calculated. The specific calculation formula is: （15） Rewrite formula (15) into an expression containing stress components: （16） wherein is the maximum principal stress, is the intermediate principal stress, is the minimum principal stress, and ; Step S447: According to the soil mechanics theory, the lateral pressure of the soil body is the same and is 0 under the undrained condition, so and the initial pore water pressure is 0, so the pore water pressure of the saturated soil body is: （17） wherein is a material constant, ; Step S448: Calculate the pore water pressure of the column body of the row row column is: （18） After rewriting formula (18), we get: （19） The super-pore water pressure of the column body of the row line column is calculated as ; The specific calculation formula is: （20）。 7. The reservoir landslide instability prediction method according to claim 6, characterized in that: Step S6 comprises the following steps: Step S61: According to the initial motion state of each column body, the initial landslide acceleration and the motion velocity of each column body are calculated. Step S62: The motion state of each column body at each time is iteratively calculated, and the landslide acceleration of each column body at each time is calculated according to the initial acceleration and the motion velocity of each column body and the motion state at each time, and then the motion velocity of each column body at each time is obtained, until the motion velocity is 0, then the calculation is stopped.
8. A reservoir area landslide instability prediction device, characterized in that, Comprise the following modules: Data acquisition module: used for acquiring the sliding zone soil porosity, sliding zone soil cohesion and sliding body density of the sliding zone soil at the sliding depth of the target landslide; Friction model module: used for acquiring and establishing the normal stress dependence model of the residual friction coefficient of the sliding zone soil and the rate dependence model of the residual friction coefficient of the sliding zone soil according to the sliding body density and the rate dependence data of the residual friction coefficient of the sliding zone soil; Fusion model module: used for coupling the normal stress dependence model of the residual friction coefficient of the sliding zone soil and the rate dependence model of the residual friction coefficient of the sliding zone soil to obtain a joint model; An acceleration calculation module is configured to discretize a target landslide into a plurality of columns, calculate the self-weight stress, hydrostatic pressure, excess pore water pressure, water resistance, and float force of each column, and obtain the cohesion of the sliding zone soil from step S1, thereby listing the dynamic equilibrium equation of each column, and solving the dynamic equilibrium equation to obtain the landslide acceleration of each column; A motion state calculation module is configured to take the moment when the target landslide starts to slide sharply as an initial time point, and calculate the motion state of each column at the initial state, including the self-weight stress, hydrostatic pressure, excess pore water pressure, water resistance, float force, and frictional resistance of the column along the sliding surface; A prediction module is configured to iteratively calculate the motion state of each column, and calculate the landslide acceleration and motion speed of each column at each time point.