Rock slope stability analysis method and system based on pore water pressure

Abstract

This application provides a method and system for analyzing the stability of rock slopes based on pore water pressure, relating to the field of geological monitoring technology. The method includes: determining a first pore water pressure based on the hydrostatic pressure distribution conditions within the open fractures at the rear edge of the target rock slope; determining a second pore water pressure based on the seepage boundary conditions within jointed fracture sections and the pressure continuity conditions at the interface between the jointed fracture sections and the open fractures at the rear edge; obtaining the total stress of the target rock slope; and determining the stability analysis result of the target rock slope based on the total stress, the first pore water pressure, and the second pore water pressure. This method can achieve refined regional characterization of pore water pressure in different seepage zones of a rock slope, thereby improving the reliability of slope stability evaluation.

Description

Technical Field

[0001] This application relates to the field of geological monitoring technology, specifically to a method and system for analyzing the stability of rock slopes based on pore water pressure. Background Technology

[0002] In existing practices for analyzing the stability of rock slopes, the determination of pore water pressure typically relies on relatively uniform empirical models or simplified theoretical formulas. These methods often treat the seepage field within the slope as a whole, using a single calculation parameter or assumption to estimate the pore water pressure for the entire area. Because the degree of fracture development, filling state, and hydraulic connectivity within the slope rock mass vary across different sections, it is difficult to guarantee the spatial accuracy of the pressure calculation.

[0003] Inaccurate calculation of pore water pressure directly affects the slope stability evaluation results based on the effective stress principle. Errors in the calculation of stability coefficient or landslide thrust often stem from underestimating or overestimating the water pressure distribution, resulting in discrepancies between the analysis conclusions and the actual engineering conditions. This can easily lead to low reliability of slope stability evaluation results, misjudging the risk of slope instability, and consequently affecting the rationality of engineering support design and disaster prevention decisions. Summary of the Invention

[0004] Based on this, this application provides a method and system for analyzing the stability of rock slopes based on pore water pressure, which can realize the refined characterization of pore water pressure in different seepage zones of rock slopes, thereby improving the reliability of slope stability evaluation.

[0005] In a first aspect, this application provides a method for stability analysis of rock slopes based on pore water pressure, comprising: determining a first pore water pressure based on the hydrostatic pressure distribution conditions within the trailing edge open fractures of a target rock slope; the target rock slope being a rock slope with trailing edge open fractures; the first pore water pressure being the pore water pressure generated by hydrostatic pressure at any location within the trailing edge open fractures; determining a second pore water pressure based on the seepage boundary conditions within jointed fracture segments and the pressure continuity conditions at the interface between the jointed fracture segments and the trailing edge open fractures; the second pore water pressure being the pore water pressure generated by seepage at any location within the jointed fracture segments; obtaining the total stress of the target rock slope; and determining the stability analysis result of the target rock slope based on the total stress, the first pore water pressure, and the second pore water pressure.

[0006] Optionally, determining the second pore water pressure based on the seepage boundary conditions within the joint fracture segment and the pressure continuity conditions at the interface between the joint fracture segment and the trailing edge open fracture includes: constructing a parallel plate fracture model; the parallel plate fracture model is a mathematical model with the seepage boundary conditions within the joint fracture segment and the pressure continuity conditions as solution constraints; and outputting the second pore water pressure at any position within the joint fracture segment based on the parallel plate fracture model.

[0007] Optionally, in the parallel plate fracture model, the water flow within the joint fracture segment is limited to constant and incompressible seepage, and the parallel plate fracture model outputs a quadratic function relationship between the second pore water pressure and the height.

[0008] Optionally, the input parameters of the parallel plate fracture model include the depth of the trailing edge opening fracture, the depth of water in the trailing edge opening fracture, the height difference between the bottom of the trailing edge opening fracture and the preset drainage outlet, and the inclination angle of the joint fracture.

[0009] Optionally, the parallel plate fracture model contains a fracture seepage energy equation, which describes the fracture flow within the joint fracture segment where there is viscous dissipation and energy is conserved along the fracture path.

[0010] Optionally, the fracture seepage energy equation is:

[0011]

[0012] in, The pore water pressure within the jointed fracture section. Let be the density of water, and k be the permeability coefficient of the joint fissure. The dip angle of the joint fissure. It is the acceleration due to gravity. Let C be the elevation difference between the target point and the preset drainage outlet, and let C be a constant determined by the seepage boundary conditions within the joint fissure section and the pressure continuity conditions at the interface between the joint fissure section and the rear edge opening fissure.

[0013] Optionally, the second pore water pressure is:

[0014] in, The second pore water pressure, The density of water, It is the acceleration due to gravity. The depth of the water in the fissure at the trailing edge. The elevation difference between the target point and the preset drain outlet. The permeability coefficient at the bottom of the fracture is... The dip angle of the joint fissure. Permeability coefficient and attenuation coefficient Pressure at target point versus height derivative Approximate value.

[0015] Optionally, the first pore water pressure is:

[0016] in, The first pore water pressure, The density of water, It is the acceleration due to gravity. The depth of the water in the fissure at the trailing edge. The height difference between the bottom of the trailing edge opening and the preset drainage outlet. The elevation difference between the target point and the preset drain outlet.

[0017] Optionally, the method further includes: Obtain the rainfall in the area where the target rock slope is located, and determine the target water depth in the rear edge opening fissure after the rainfall based on the rainfall; The first pore water pressure and the second pore water pressure are determined based on the target water depth, and the water pressure risk level of the target rock slope under the rainfall is determined based on the first pore water pressure and the second pore water pressure, or it is determined whether the rainfall affects the stability of the target rock slope.

[0018] Secondly, this application provides a rock slope stability analysis system based on pore water pressure, comprising: The first calculation module is used to determine the first pore water pressure based on the hydrostatic pressure distribution conditions within the trailing edge open fissure of the target rock slope; the target rock slope is a rock slope with trailing edge open fissures; the first pore water pressure is the pore water pressure generated by hydrostatic pressure at any position within the trailing edge open fissures. The second calculation module is used to determine the second pore water pressure based on the seepage boundary conditions within the joint fracture segment and the pressure continuity conditions at the interface between the joint fracture segment and the trailing edge open fracture; the second pore water pressure is the pore water pressure generated by seepage at any location within the joint fracture segment. The analysis module is used to obtain the total stress of the target rock slope, and determine the stability analysis result of the target rock slope based on the total stress, the first pore water pressure and the second pore water pressure.

[0019] Compared with existing technologies, the beneficial effects of this application are as follows: By separately determining the first pore water pressure within the rear-edge opening fracture and the second pore water pressure within the joint fracture section, a refined zonal characterization of pore water pressure in different seepage zones of rock slopes is achieved. By combining the total stress with the pore water pressure of the corresponding section, effective stress parameters for slope stability analysis can be directly obtained. The method provided in this application simplifies the error by uniformly treating the entire seepage path as static water or pure seepage, thereby improving the calculation accuracy of pore water pressure. Since the first and second pore water pressures reflect the actual hydraulic characteristics of the static water zone and the seepage zone, respectively, the stability analysis results determined by both and the total stress can more realistically reflect the mechanical state of the slope under the action of pore water, thus improving the reliability of slope stability evaluation. Attached Figure Description

[0020] Figure 1 A schematic diagram illustrating the steps of the rock slope stability analysis method based on pore water pressure provided in this application embodiment.

[0021] Figure 2 This is a simplified schematic diagram of a layered rock slope provided in an embodiment of this application.

[0022] Figure 3 A schematic diagram of the architecture of a rock slope stability analysis system based on pore water pressure provided in this application embodiment. Detailed Implementation

[0023] The present application will now be described in further detail with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the subject matter of the present application to the following embodiments. All technologies implemented based on the content of the present application fall within the scope of protection of the present application.

[0024] In the description of the embodiments of this application, technical terms such as "first" and "second" only distinguish one entity or operation from another, and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] Please refer to Figure 1, Figure 1 This is a schematic diagram illustrating the steps of a rock slope stability analysis method based on pore water pressure provided in an embodiment of this application. The method may include: S1. Determine the first pore water pressure based on the hydrostatic pressure distribution conditions within the open fissures at the rear edge of the target rock slope.

[0027] S2. Based on the seepage boundary conditions within the jointed fracture section and the pressure continuity conditions at the interface between the jointed fracture section and the rear-edge opening fracture, the second pore water pressure is determined.

[0028] S3. Obtain the total stress of the target rock slope, and determine the stability analysis results of the target rock slope based on the total stress, the first pore water pressure, and the second pore water pressure.

[0029] In this embodiment, the target rock slope is a rock slope with a trailing-edge opening fissure. The trailing-edge opening fissure is a vertical or near-vertical opening crack located at the trailing edge of the slope, filled with free water. The pores of the rock slope include opening fissure sections and joint fissure sections. The first pore water pressure is the pore water pressure generated by hydrostatic pressure at any location within the trailing-edge opening fissure; its physical meaning is the pressure value in the hydrostatic pressure field. The hydrostatic pressure distribution condition is that the water is in a static state within the trailing-edge opening fissure, and the pore water pressure follows a linear hydrostatic pressure distribution law, that is, the pressure at any location is equal to the product of the water density, gravitational acceleration, and the height of the water column above that location.

[0030] The jointed fracture section is an inclined seepage channel connecting the bottom of the rear-edge open fracture to the pre-designated drainage outlet on the slope. This channel corresponds to the interlayer fractures in the layered rock mass, and the water flows along an approximately straight path. The seepage boundary conditions are the pressure or flow constraints that the water flow within the jointed fracture section must satisfy at the infiltration and effluent boundaries. Specifically, these include zero second pore water pressure at the pre-designated drainage outlet and continuous pressure at the boundary between the jointed fracture section and the rear-edge open fracture. The pressure continuity condition is that at the bottom of the rear-edge open fracture, the second pore water pressure within the jointed fracture section is numerically equal to the first pore water pressure at the same location within the rear-edge open fracture, ensuring that the pressure does not change abruptly throughout the seepage path.

[0031] The second pore water pressure is the pore water pressure generated by seepage at any location within the joint and fracture segment; this pressure is affected by seepage velocity, viscous dissipation, and location head, and exhibits a nonlinear distribution. The total stress is the total stress field generated by the self-weight of the soil and rock mass and the external load in the target rock slope, and its value is equal to the sum of the effective stress and the pore water pressure.

[0032] It should be understood that the rock slope stability analysis method provided in this application is not strictly limited to layered rock slopes. Because the path of water seepage along the bedding plane fissures in layered rock slopes can be geometrically approximated as a straight line, this characteristic simplifies the seepage problem to a one-dimensional flow problem. Based on the same principle, as long as the seepage path in the target rock slope can be approximated as a straight line—for example, slopes with dominant joint surfaces or fault fracture zones forming approximately straight seepage channels—the method provided in this application can be used for stability analysis. In practical applications, the method provided in this application only requires confirming the presence of open fissures at the rear edge of the slope and that the seepage path can be approximated as a straight line. The pore water pressure can then be directly calculated and stability analysis conducted using the method of this application, without needing to re-derive the model for different rock strata orientations.

[0033] For example, please see Figure 2 , Figure 2 This is a simplified schematic diagram of a layered rock slope provided in an embodiment of this application. There is a widening fissure at one of the trailing edges, with a fissure depth of d, and the water depth within the widening fissure is... The height difference between the bottom of the opening crack and the drainage outlet is In a rock slope containing fissure water pressure. The density of water is... The dip angle of the joints and fissures is Establish a coordinate system with the drain outlet as the origin, with the positive x-axis pointing to the right and the positive y-axis pointing upwards, and the acceleration due to gravity as g.

[0034] The fracture depth *d* can be obtained using either the ultrasonic method or the ground-penetrating radar method. The ultrasonic method involves placing transmitting and receiving probes on both sides of the fracture at its trailing edge, measuring the calibrated wave velocity in the intact rock mass and the propagation time across the fracture, and then calculating the fracture depth *d* using geometric relationships. The ground-penetrating radar method, for concealed and deeper fractures, utilizes the strong reflection of high-frequency electromagnetic waves upon encountering fracture water, and calculates the fracture depth *d* from the two-way travel time. The depth of water in the opened fracture is... The elevation difference between the bottom of the open fracture and the drainage outlet can be obtained through on-site measurement methods, such as borehole water level observation, direct measurement of water depth through the fracture, and piezometer monitoring. It is obtained by subtracting the fracture depth d from the measured slope height h. The dip angle of the joint fracture. Geological compasses can be used to measure the dip angle of exposed joints and fissures on the slope surface, thereby inferring the dip angle of joints in the same deep rock mass at the same location in the same stratum. For steep slopes where it is impossible to approach the structural surfaces of the slope, three-dimensional laser scanning can be used to measure the coordinates of the joints at multiple points, fit the plane equation, and calculate the dip angle from the plane normal vector.

[0035] Based on the hydrostatic pressure distribution conditions, the first pore water pressure in the fractured section can be determined as:

[0036] in, The first pore water pressure, The density of water, It is the acceleration due to gravity. The depth of the water in the fissure at the trailing edge. The height difference between the bottom of the rear edge opening crack and the pre-set drainage outlet. The elevation difference between the target point and the aforementioned preset drainage outlet.

[0037] In some embodiments, the method for determining the second pore water pressure based on the seepage boundary conditions within the joint fracture segment and the pressure continuity conditions at the interface between the joint fracture segment and the trailing edge open fracture can include: Construct a parallel plate fracture model; the parallel plate fracture model is a mathematical model with seepage boundary conditions and pressure continuity conditions within the joint fracture segment as solution constraints; output the second pore water pressure at any position within the joint fracture segment based on the parallel plate fracture model.

[0038] The input parameters for the parallel plate fracture model include the depth of the trailing edge opening fracture, the depth of water in the trailing edge opening fracture, the height difference between the bottom of the trailing edge opening fracture and the preset drainage outlet, and the dip angle of the joint fracture.

[0039] For example, regarding water flow within jointed fracture sections, since the fracture width is much smaller than the fracture's extension length and height, the water flows in a thin layer within the fracture, conforming to one-dimensional flow characteristics. The flow velocity within the fracture is relatively low, mostly laminar, with relatively small viscous dissipation, and the flow can be considered steady and incompressible. Based on these characteristics, jointed fracture sections can be generalized as parallel plate fracture models. Under laminar, steady, and incompressible one-dimensional seepage conditions, the energy conservation relationship of the water flow holds; therefore, fracture water flow can be described and calculated using Bernoulli's equation:

[0040] Wherein, C is a constant determined by the seepage boundary conditions within the jointed fracture section and the pressure continuity conditions at the interface between the jointed fracture section and the opening fracture at the rear edge.

[0041] Meanwhile, due to the narrow fissure and low water velocity, the water flow exhibits a laminar flow state, approximately satisfying Darcy's law:

[0042] Where v is the water flow velocity, k is the permeability coefficient, and i is the hydraulic gradient.

[0043] Please continue reading. Figure 2 In the jointed fracture section, the slope distance between two adjacent points is The elevation difference is The pore water pressure difference between the two points is The hydraulic gradient i can be expressed as Considering the dip angle α of the joint fracture, and The relationship between them is Therefore, hydraulic gradient Transforming into differential form, it becomes:

[0044] therefore:

[0045] Substituting the velocity expression into Bernoulli's equation yields the relationship between the pore water pressure p within the joint fracture segment and the elevation difference of the target point relative to the preset drainage outlet. The ordinary differential equation, also known as the fracture seepage energy equation:

[0046] in, The pore water pressure within the jointed fracture section. The density of water, The permeability coefficient of the joint fracture is... The dip angle of the joint fracture. It is the acceleration due to gravity. The elevation difference between the target point and the preset drainage outlet. This is a constant determined by the seepage boundary conditions within the jointed fracture segment and the pressure continuity condition at the interface between the jointed fracture segment and the opening fracture at the trailing edge. The fracture seepage energy equation is used to describe fracture flow with viscous dissipation and energy conservation along the flow path.

[0047] Unlike the permeability coefficient of horizontal strata, the permeability coefficient of joints and fissures should vary at different locations on a slope. The permeability coefficient at different locations within a joint or fissure is related to the degree of fissure opening, which in turn is related to the normal stress at the location of the fissure. When the normal stress at the location of the fissure is greater, the joint surface is compressed and pressed together, the degree of fissure opening is smaller, the resistance to water flow is stronger, and the permeability coefficient is lower. Furthermore, the area near the drainage outlet is a free surface, where the fissures are fully open, and the permeability coefficient should reach its maximum value. The permeability coefficient at the bottom of the vertically opened fracture... Minimum. Since the permeability coefficient on the joint surface gradually decreases from left to right, and considering that studies have shown that increasing the degree of fracture opening leads to a near-cubic increase in the permeability coefficient, and also considering that increasing the stress on the joint surface will not completely close the water flow channel, further increasing the normal stress has little effect on reducing the permeability coefficient, the expression for the permeability coefficient on the joint surface should be a decreasing function with a gradually flattening tangent. Therefore:

[0048] Depend on hour, Solve

[0049] Substituting the expression for the permeability coefficient into Bernoulli's equation:

[0050] Since the differential equation above is difficult to solve directly, this application uses numerical solution. A calculation table can be compiled based on the equations listed below to calculate the pore water pressure at all locations. The joint surface AB is divided into n equal parts, with the division points from left to right as follows: , … Drainage outlet point A is denoted as Point B is denoted as .exist arrive The i-th point The vertical coordinate height is:

[0051] The i-th point The permeability coefficient is:

[0052] The i-th point The pore water pressure is p i The derivative of pore water pressure is obtained using the finite difference method:

[0053] Finally, the second pore water pressure at each target point can be determined by solving the following system of equations. :

[0054] in, and The value is a preset boundary value at both ends. Within the preset boundary range, the second pore water pressure at any target point within the joint fracture segment can be determined. The height difference between the target point and the preset drain outlet The functional relationship is:

[0055] in, The second pore water pressure, The density of water, It is the acceleration due to gravity. The depth of the water in the fissure at the trailing edge. The elevation difference between the target point and the preset drain outlet. The permeability coefficient at the bottom of the fracture is... The dip angle of the joint fissure. This is the nonlinear term resulting from the decrease in permeability coefficient. Permeability coefficient and attenuation coefficient Pressure at target point versus height derivative Approximate value.

[0056] After obtaining the total stress of the target rock slope, subtract the first pore water pressure at the corresponding location from the total stress. Or second pore water pressure The effective stress of the rock and soil mass can then be obtained.

[0057] For any calculated location within the slope, the effective stress of the soil and rock mass at that location can be obtained by subtracting the corresponding pore water pressure from the total stress at that location. If the calculated location is within the open fracture section at the rear edge, the first pore water pressure should be subtracted. If the calculation location is within a jointed or fractured section, then subtract the second pore water pressure. Effective stress is the essential stress parameter controlling the shear strength and deformation behavior of soil and rock masses. Based on effective stress, the stability coefficient of a slope can be calculated using the limit equilibrium method or the strength reduction method, or the landslide thrust can be calculated using the transfer coefficient method, etc. When the stability coefficient is greater than a set threshold (which may vary depending on the engineering level), the slope is considered to be in a stable state; otherwise, it is considered to be unstable or in a state requiring reinforcement.

[0058] In the above implementation process, by separately determining the first pore water pressure within the rear-edge opening fracture and the second pore water pressure within the joint fracture section, a refined zonal characterization of pore water pressure in different seepage zones of the rock slope is achieved. By combining the total stress with the pore water pressure of the corresponding zone, effective stress parameters for slope stability analysis can be directly obtained. The method provided in this application simplifies the error by uniformly treating the entire seepage path as static water or pure seepage, thus improving the calculation accuracy of pore water pressure. Since the first and second pore water pressures reflect the actual hydraulic characteristics of the static water zone and the seepage zone, respectively, the stability analysis results determined by both and the total stress can more realistically reflect the mechanical state of the slope under the action of pore water, thereby improving the reliability of slope stability evaluation.

[0059] In addition, the method of this application does not require full-domain numerical simulation of complex seepage fields. It only needs to utilize the hydrostatic pressure distribution of the rear-edge open fractures and the boundary and continuity conditions of the joint fracture segments to complete the calculation, which can reduce the computational complexity of rock slope stability.

[0060] In other embodiments, the method provided in this application can also be used to provide a slope water pressure risk prediction function based on rainfall. The method provided in the embodiments of this application may further include: Obtain the rainfall in the area where the target rock slope is located, and determine the target water depth in the open fissures at the rear edge after the rainfall based on the rainfall. Determine the first pore water pressure and the second pore water pressure based on the target water depth, and determine the water pressure risk level of the target rock slope under the rainfall based on the first pore water pressure and the second pore water pressure, or determine whether the rainfall affects the stability of the target rock slope.

[0061] Specifically, the rainfall in the area where the target rock slope is located can be obtained first. This rainfall can be a predicted value from a weather forecast or a cumulative rainfall value measured by a rain gauge station.

[0062] Based on the rainfall amount and the geometry of the open fissures at the rear edge of the slope (such as fissure aperture and catchment area), the target water depth to be reached in the open fissures after rainfall can be determined. This target water depth reflects the actual water level height within the fissures after rainfall infiltration. The first and second pore water pressures are then recalculated based on this target water depth, using the same calculation method as described above, which will not be repeated here.

[0063] Using the recalculated first and second pore water pressures as input, the water pressure risk level of the target rock slope under the influence of this rainfall can be further determined, or it can be directly determined whether the rainfall has a substantial impact on the stability of the slope. The water pressure risk level can be divided into several levels (such as low risk, medium risk, and high risk), each corresponding to different stability coefficient thresholds or landslide thrust ranges.

[0064] Through the above steps, this application can also achieve rapid prediction of rainfall-induced slope instability, providing quantitative basis for engineering early warning and disaster prevention and mitigation, thereby adding risk assessment function under rainfall scenarios on the basis of slope stability analysis.

[0065] Based on the same concept, this application also provides a rock slope stability analysis system based on pore water pressure. Please refer to... Figure 3 , Figure 3 A schematic diagram of the architecture of a rock slope stability analysis system based on pore water pressure provided in this application embodiment. The rock slope stability analysis system 30 based on pore water pressure may include: The first calculation module 31 is used to determine the first pore water pressure based on the hydrostatic pressure distribution conditions in the rear edge opening fissure of the target rock slope; the target rock slope is a rock slope with a rear edge opening fissure; the first pore water pressure is the pore water pressure generated by hydrostatic pressure at any position in the rear edge opening fissure. The second calculation module 32 is used to determine the second pore water pressure based on the seepage boundary conditions within the joint fracture section and the pressure continuity conditions at the interface between the joint fracture section and the rear edge opening fracture; the second pore water pressure is the pore water pressure generated by seepage at any position within the joint fracture section. Analysis module 33 is used to obtain the total stress of the target rock slope and determine the stability analysis results of the target rock slope based on the total stress, the first pore water pressure and the second pore water pressure.

[0066] It should be understood that when the various modules of the system provided in the above embodiments are working, the division of each functional module in the above description is only used as an example. In actual applications, the above functions can be assigned to different functional modules as needed. That is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0067] The functional modules in the above embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of the embodiments of this application.

[0068] Based on the same concept, embodiments of this application also provide a computer device, which may include a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the methods described above.

[0069] Based on the same concept, embodiments of this application also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the methods described above.

[0070] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A rock slope stability analysis method based on pore water pressure, characterized by, include: The first pore water pressure is determined based on the hydrostatic pressure distribution conditions within the open fissures at the rear edge of the target rock slope. The target rock slope is a rock slope with a trailing edge opening fissure; the first pore water pressure is the pore water pressure generated by hydrostatic pressure at any position within the trailing edge opening fissure; Based on the seepage boundary conditions within the joint fracture segment and the pressure continuity conditions at the interface between the joint fracture segment and the trailing edge open fracture, the second pore water pressure is determined; the second pore water pressure is the pore water pressure generated by seepage at any location within the joint fracture segment. The total stress of the target rock slope is obtained, and the stability analysis results of the target rock slope are determined based on the total stress, the first pore water pressure, and the second pore water pressure.

2. The method for analyzing the stability of a rock slope based on pore water pressure according to claim 1, wherein The determination of the second pore water pressure based on the seepage boundary conditions within the jointed fracture segment and the pressure continuity conditions at the interface between the jointed fracture segment and the trailing edge opening fracture includes: Construct a parallel plate fracture model; the parallel plate fracture model is a mathematical model with the seepage boundary conditions and the pressure continuity conditions within the joint fracture segment as the solution constraints; The second pore water pressure at any position within the joint fracture segment is output based on the parallel plate fracture model.

3. The method for analyzing the stability of rock slopes based on pore water pressure according to claim 2, characterized in that, In the parallel plate fracture model, the water flow within the joint fracture segment is limited to constant and incompressible seepage, and the parallel plate fracture model outputs a quadratic function relationship between the second pore water pressure and the height.

4. The method for analyzing the stability of rock slopes based on pore water pressure according to claim 2, characterized in that, The input parameters of the parallel plate fracture model include the depth of the trailing edge opening fracture, the depth of water in the trailing edge opening fracture, the height difference between the bottom of the trailing edge opening fracture and the preset drainage outlet, and the inclination angle of the joint fracture.

5. The method for analyzing the stability of rock slopes based on pore water pressure according to any one of claims 2-4, characterized in that, The parallel plate fracture model contains a fracture seepage energy equation, which describes the fracture flow within the joint fracture segment where there is viscous dissipation and energy is conserved along the fracture path.

6. The method for analyzing the stability of rock slopes based on pore water pressure according to claim 1, characterized in that, The method further includes: Obtain the rainfall in the area where the target rock slope is located, and determine the target water depth in the rear edge opening fissure after the rainfall based on the rainfall; The first pore water pressure and the second pore water pressure are determined based on the target water depth, and the water pressure risk level of the target rock slope under the rainfall is determined based on the first pore water pressure and the second pore water pressure, or it is determined whether the rainfall affects the stability of the target rock slope.

7. A rock slope stability analysis system based on pore water pressure, characterized in that, include: The first calculation module is used to determine the first pore water pressure based on the hydrostatic pressure distribution conditions in the open fissures at the rear edge of the target rock slope. The target rock slope is a rock slope with a trailing edge opening fissure; the first pore water pressure is the pore water pressure generated by hydrostatic pressure at any position within the trailing edge opening fissure; The second calculation module is used to determine the second pore water pressure based on the seepage boundary conditions within the joint fracture segment and the pressure continuity conditions at the interface between the joint fracture segment and the trailing edge open fracture; the second pore water pressure is the pore water pressure generated by seepage at any location within the joint fracture segment. The analysis module is used to obtain the total stress of the target rock slope, and determine the stability analysis result of the target rock slope based on the total stress, the first pore water pressure and the second pore water pressure.

Images