Method for identifying and extracting potential sliding surface of side slope in two-dimensional numerical simulation calculation

Abstract

The invention relates to a method for identifying and extracting a potential sliding surface of a side slope in two-dimensional numerical simulation calculation, and belongs to the field of traffic side slope engineering. The method comprises the following steps of: determining an identified potential sliding surface boundary position as a potential sliding surface lower or upper edge boundary position according to a position relationship between side slope surface numerical value units with minimum and secondary minimum local safety coefficients; and finally, sequentially connecting the identified and extracted potential sliding surface points to obtain a two-dimensional side slope potential sliding surface. According to the method, a strength reduction technology does not need to be introduced, a rock-soil body shear strength criterion is not limited, the two-dimensional side slope potential sliding surface can be automatically and intelligently identified and extracted, the obtained potential sliding surface conforms to a side slope shear failure mechanism, and the actual failure form of the two-dimensional side slope in a real scene can be effectively displayed; the method has the advantages of being wide in application range, high in precision, good in universality, good in effect, low in cost and the like, and is used for providing a powerful scientific basis for slope potential instability range prediction and reinforcement area determination in actual engineering.

Description

Technical Field

[0001] The invention belongs to the field of traffic slope engineering, and in particular relates to a method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations. Background Art

[0002] Landslide is a common natural disaster, and the losses caused by it every year are quite huge. In order to reduce the losses caused by landslide disasters or avoid them as much as possible, it is very necessary to accurately determine the potential sliding surface of the slope.

[0003] After determining the potential sliding surface of the slope, on the one hand, the specific location and shape of the potential sliding surface can be obtained to guide engineering design and construction optimization, and provide a prerequisite for selecting appropriate support structures and reinforcement measures, thereby ensuring the effectiveness and economy of engineering reinforcement measures; on the other hand, the layout range of the slope displacement monitoring equipment can be clarified for real-time monitoring of slope deformation, providing an information basis for taking emergency measures and accurate early warning of landslide disasters.

[0004] The existing methods for determining the potential sliding surface of the slope mainly include theoretical analysis method, numerical simulation method and on-site monitoring method. The theoretical analysis method includes the limit equilibrium method based on the rigid body limit equilibrium theory and the limit analysis method based on the plastic mechanics theory. For both the limit equilibrium method and the limit analysis method, it is necessary to pre-assume the sliding surface mode (such as the former is the arc sliding surface mode, and the latter is the logarithmic spiral sliding surface mode), and then establish the slope safety factor calculation formula according to their respective theories (such as the former is to make reasonable assumptions about the point or size of action of the inter-strip force and apply the mechanical equilibrium conditions, and the latter is to apply the functional equilibrium relationship of the sliding body). Based on this, after setting the corresponding size range for the sliding surface of the pre-assumed mode, the minimum value of the slope safety factor can be used as the search target to determine the potential sliding surface of the slope. The numerical simulation method establishes a numerical model of the slope based on the actual geometric shape of the slope and reasonable physical and mechanical parameters, and uses numerical calculation to obtain the slope stress, strain and displacement field to determine whether the slope is unstable and damaged. In the numerical calculation process, the strength reduction technology is usually introduced to gradually reduce the shear strength of the rock and soil, thereby forcing the slope to shear failure, and then determine the potential sliding surface of the slope based on the connected shear strain plastic zone during shear failure. The field monitoring method determines the layout range and location of the slope surface and deep deformation monitoring points based on the acquired slope geological conditions, rock and soil characteristics and historical landslides, and then regularly collects the slope surface and deep deformation data, and roughly determines the potential sliding range of the slope based on the incremental change relationship between the surface and deep deformation of the slope over time, and at the same time, warns of slope landslide disasters based on this.

[0005] Among the above methods for determining the potential sliding surface of slopes, the theoretical analysis method needs to assume the sliding surface mode in advance, which may not be consistent with the actual situation. In addition, the limit equilibrium method, which is the most widely used in actual engineering, mainly limits the shear strength criterion of rock and soil to the linear MC strength criterion, making it difficult to obtain reliable results of slope stability analysis under complex conditions. The limit analysis method needs to introduce strength reduction technology and use the reduced sliding surface strength parameters as the control parameters of the sliding surface shape, which will cause the potential sliding surface obtained to be distorted to a certain extent. Although the numerical simulation method has the advantages of high accuracy, wide application range, dynamic analysis and multi-field coupling, the numerical simulation method also introduces strength reduction technology, resulting in the slope stress field after the strength parameter reduction in the numerical analysis is not the actual stress field, and the potential sliding surface inferred is not the actual potential sliding surface. In addition, there are multiple criteria for slope instability identification in numerical analysis, and there are calculation result deviations between different criteria. The on-site monitoring method can roughly determine the shape and position of the potential sliding surface of the slope based on the actual monitoring data. However, the accuracy of determining the potential sliding surface of the slope is closely related to the density of the monitoring points. To obtain a more accurate potential sliding surface, a larger number of monitoring points and corresponding monitoring components are required, which leads to an increase in the corresponding labor and monitoring costs. In addition, the reliability, durability and accuracy of the monitoring components also restrict the accuracy of the identification of the potential sliding surface of the slope.

[0006] Chinese invention patent CN201910211393.3 discloses a slope stability analysis system based on the dynamic strength reduction DDA method. In order to consider the different degree of damage to the rock mass structural surface in the real situation, the system proposes to dynamically reduce the shear strength parameters c and c of the block structural surface whose displacement change is not less than the threshold. In the program calculation, the shear strength parameters of the block structural surface are reduced at regular time steps (10,000 steps, each time step is 0.001s) according to the relationship between the relative displacement change of the block and the threshold. The shear strength parameters of the structural surface whose displacement change meets the requirements are reduced. The reduction coefficient starts from 1.000 and increases by 0.001 successively until a sharp deformation occurs. At this time, its value is the safety factor of the slope sliding surface. The rock mass in the dangerous area of ​​the slope can be stripped in advance according to the retrieved sliding surface position. It is highly practical and contributes a new means to the stability analysis and management of multiple sliding surfaces of the slope. This invention patent utilizes the DDA method and applies dynamic strength reduction technology to realize numerical analysis of slope stability; however, since this invention patent introduces strength reduction technology, the slope stress field after the strength parameter reduction in the numerical analysis is not the actual stress field, and thus the inferred potential sliding surface of the slope is not the actual sliding surface of the slope; in addition, this patent does not specify how to use numerical means to extract and identify the potential sliding surface of the slope; therefore, this invention patent still lacks in implementation accuracy and effect.

[0007] Chinese invention patent CN202210520129.X discloses a non-circular slope sliding surface search method based on an improved wolf pack algorithm, including the following steps: establish a numerical model and extract the basic information of the numerical model; classify the cells according to the unit material number and draw the slope image in layers; set the slope surface area within a certain range of the top and foot of the slope image as the possible activity range of the head wolf and the female wolf; the head wolf, the female wolf, and the scout wolf walk with a fixed step length to form a wolf pack combination and determine the stress information of each point on the path; calculate the sliding force and anti-sliding force between two adjacent wolves based on the stress information, define the fitness of the wolf pack as the inverse of the safety factor, and use the spline curve with the largest fitness value as the optimal spline curve. This invention can make up for the shortcomings of the circular sliding surface assumption that does not match the actual situation, quickly and accurately determine the position of the slope sliding surface and calculate the safety factor. Specifically, the invention patent uses an improved wolf pack algorithm to search for potential non-circular sliding surfaces of the slope. During the search for potential sliding surfaces, the sliding surface is divided into three segments, and the curves of each sliding surface segment are assumed to be smooth and continuous cubic spline curves. Based on this, the slope safety factor is solved according to the stress information of each sliding surface segment and the shear strength criterion of the rock and soil body. At the same time, the potential sliding surface corresponding to the minimum value of the slope safety factor is used as the search target. Therefore, the invention patent does not meet the requirement that all parts of the sliding surface are subject to the shear failure mechanism of the slope, so that the potential sliding surface of the slope determined by the search of the invention patent will be different from the actual sliding surface of the slope; in addition, the acquisition of stress information of each sliding surface segment also needs to be applied to machine learning methods, which increases the complexity of the implementation of the patent and greatly reduces the practicality of the patent.

[0008] As engineering construction moves towards dangerous mountainous areas, slope engineering design and construction become more complicated, and the task of timely and effective landslide prevention and control is very urgent. The need to accurately determine the potential sliding surface of the slope has become very urgent. In order to meet this requirement, it is necessary to find a method for determining the potential sliding surface of the slope that has the characteristics of wide application range, high precision, good versatility, good effect, and has the characteristics of automation and intelligence.

[0009] In other words, this field requires a new method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations. Summary of the invention

[0010] Therefore, the present invention provides a method for identifying and extracting a potential sliding surface of a slope in a two-dimensional numerical simulation calculation, the method comprising the following steps:

[0011] Step S1: Establish a two-dimensional slope numerical calculation model, carry out numerical calculation, and extract information of each numerical unit in the numerical model;

[0012] Step S2: Calculate the local safety factor of each numerical unit in the numerical model, and obtain the angle α between the most unfavorable shear direction of each numerical unit and the horizontal plane direction critical ;

[0013] Step S3: determining the slope surface numerical unit with the smallest local safety factor, and judging whether the determined slope surface numerical unit is the lower edge boundary position of the potential sliding surface or the upper edge boundary position of the potential sliding surface based on the positional relationship between the slope surface numerical unit with the smallest local safety factor and the slope surface numerical unit with the second smallest local safety factor;

[0014] Step S4: taking the center point of the determined slope surface numerical unit as the starting point for potential sliding surface identification and extraction, and setting the coordinates of the center point to (x0, z0);

[0015] Step S5: Apply the segmented step-by-step identification method to solve the position of the next unknown potential sliding surface point i based on the previous known potential sliding surface point i–1. The specific calculation formula is x i =x i–1 +Δd×cosα i–1 and z i =z i–1 +Δd×sinα i–1 ; Among them, α i–1 is the angle between the most unfavorable shear direction of the numerical unit where point i–1 is located and the horizontal plane direction; and if the determined numerical unit of the slope surface is the lower edge boundary position of the potential sliding surface, Δd is taken as a positive value; otherwise, Δd is taken as a negative value;

[0016] Among them, (x i–1 , z i–1 ) is the coordinate of the last known potential sliding surface point i–1, (x i , z i ) is the coordinate of the next unknown potential sliding surface point, Δd is the length of the segmented sliding surface, α i–1 is the angle between the most unfavorable shear direction of the numerical unit where point i–1 is located and the horizontal plane direction;

[0017] Step S6: Calculate the sum of the volumes of the spatial geometric bodies formed by the potential sliding surface point i and the vertices on each side surface in each numerical unit, and determine the numerical unit where the potential sliding surface point i is located based on the sum of the volumes being equal to the volume of a certain numerical unit;

[0018] Step S7: judging whether the potential sliding surface point i exceeds the slope surface according to whether the potential sliding surface point is located on a certain numerical unit; if the potential sliding surface point i exceeds the slope surface, the identification and extraction of the potential sliding surface is stopped; otherwise, repeating steps S5 to S6;

[0019] Step S8: sequentially connect the identified and extracted potential sliding surface points to obtain a two-dimensional potential sliding surface of the slope.

[0020] In a specific implementation, step S2 specifically includes the following steps:

[0021] Step S2-1: Let the general expression of the shear strength criterion of rock and soil be τ f =f(σ), where σ is the normal stress on the action surface, τ f is the shear strength on the action surface;

[0022] Step S2-2: Based on the Mohr stress circle reflecting the stress state of the numerical unit, determine the value range of the normal stress σ on the surface acting in different directions in the numerical unit as [σ3, σ1], and obtain the shear stress on the surface acting in different directions under the corresponding normal stress in the numerical unit as τ = [(σ1–σ)(σ–σ3)] 1 / 2 ; Among them, σ3 is the minor principal stress of the numerical unit, and σ1 is the major principal stress of the numerical unit;

[0023] Step S2-3: Combined with the shear strength criterion of rock and soil, the shear strength on the surface in different directions under the corresponding normal stress is calculated as τ f =f(σ);

[0024] Step S2-4: Calculate the shear strength τ on the action surface according to the safety factor definition f The ratio k of shear stress τ s , and k s =f(σ) / [(σ1–σ)(σ–σ3)] 1 / 2 ;

[0025] Step S2-5: When the normal stress σ is in the interval [σ3, σ1], use the mathematical extreme value method to solve k s The minimum value of s ), which is the local safety factor F of the numerical unit s_Local , that is, F s_Local =min(k s );

[0026] Step S2-6: The most unfavorable shear direction based on the numerical unit is k s The direction of the action surface corresponding to the minimum value is taken. The relationship between the normal stress σ and the angle α on the action surface in different directions in the numerical unit is σ=(σ3+σ1) / 2–[(σ1–σ3) / 2]cos2α. The angle between the most unfavorable shear direction of the numerical unit and the direction of the small principal stress action surface is solved as α k =(1 / 2)×arcos{[(σ3+σ1)–2σ k ] / (σ1–σ3)}, where σ k k s The normal stress on the corresponding action surface when the minimum value is taken;

[0027] Step S2-7: Using the relationship σ=(σ3+σ1) / 2–[(σ1–σ3) / 2]cos2α, solve for the angle α between the horizontal plane and the minor principal stress action surface z =(1 / 2)×arcos{[(σ3+σ1)–2σ z ] / (σ1–σ3)}; σ z is the normal stress of the numerical unit along the vertical direction;

[0028] Step S2-8: Based on the angle between the most unfavorable shear direction of the numerical unit and the direction of the minor principal stress action surface and the angle between the horizontal plane and the minor principal stress action surface, the angle between the most unfavorable shear direction and the horizontal plane is deduced to be α critical =α z –α k , where α critical When it is greater than 0, the angle direction is counterclockwise, otherwise it is clockwise.

[0029] In a specific implementation, the slope meets the generalized nonlinear HB strength criterion, and in step S2, the shear strength calculation formula of the rock and soil mass is:

[0030]

[0031] Among them, m b is a material constant, s is a parameter reflecting the degree of rock mass fragmentation, and α is a constant related to the rock mass structure and surface conditions. is the instantaneous internal friction angle of the rock mass.

[0032] In a specific implementation, in step S2, the parameter m b , s, α and The calculation formulas are:

[0033]

[0034] α=0.5+(1 / 6)×[exp(–GSI / 15)–exp(–20 / 3)]

[0035]

[0036] Among them, GSI is the geological strength index, σ c is the uniaxial compressive strength of intact rock, m i is the material constant of intact rock, and D is the disturbance factor of the rock mass.

[0037] In a specific implementation, in step S5, after extracting the coordinates (x0, z0) of the center point, the coordinates are extended upward along the sliding trend, and each extension length is Δd, where Δd is 0.1-0.5m, and then the segmented step-by-step identification method is applied to solve the position of the next unknown potential sliding surface point i based on the last known potential sliding surface point i-1; and in order to meet the concave characteristics of the sliding surface, α i–1 Should satisfy α i–1 ≥α i–2 Otherwise, if α i–1 <α i–2 , then let α i–1 =α i–2 .

[0038] In a specific implementation, using the software FLAC 3D Conduct numerical simulation analysis.

[0039] The advantages of the invention are as follows: the method provided by the invention does not need to introduce strength reduction technology and does not limit the shear strength criterion of rock and soil. After obtaining the slope stress field by numerical simulation calculation, the potential sliding surface of the two-dimensional slope can be automatically identified and extracted. The obtained potential sliding surface conforms to the shear failure mechanism of the slope and can effectively show the actual failure form of the two-dimensional slope in the real scene; at the same time, the segmented step-by-step identification method can better control the precision of the potential sliding surface identification and extraction, which is conducive to the intelligent identification and extraction of the two-dimensional potential sliding surface. Therefore, the present invention has the characteristics of wide application range, high precision, good versatility, good effect, low cost, etc., and has the characteristics of automation and intelligence, which can provide a strong scientific basis for the prediction of the potential instability range of the slope and the determination of the reinforcement area in actual engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the two-dimensional slope numerical model of the present invention.

[0041] Figure 2 It is a schematic diagram of the numerical unit stress analysis in the present invention.

[0042] Figure 3 The present invention provides a flowchart for calculating the local safety factor of the numerical unit and determining the most unfavorable shear direction.

[0043] Figure 4 The figure is a schematic diagram for determining the numerical unit of the slope surface layer according to the present invention.

[0044] Figure 5 The figure is a schematic diagram for determining the position of the lower or upper boundary of a potential sliding surface according to the present invention.

[0045] Figure 6 This is a schematic diagram of the step-by-step identification of the potential sliding surface direction and position according to the present invention.

[0046] Figure 7 The present invention is a schematic diagram for determining the numerical unit where the sliding surface point is located.

[0047] Figure 8 It is a schematic diagram of identifying the sliding surface point beyond the slope surface of the present invention.

[0048] Fig. 9 The present invention provides a flowchart for the implementation of identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations.

[0049] In the figure: 1. Two-dimensional slope numerical model; 2. Numerical unit; 3. Minor principal stress action surface; 4. Major principal stress action surface; 5. Horizontal plane; 6. Normal stress on the action surfaces in different directions in the numerical unit; 7. Shear stress on the action surfaces in different directions in the numerical unit; 8. Slope surface; 9. Boundary surface; 10. Slope surface numerical unit; 11. Slope surface numerical unit with the smallest local safety factor; 12. Slope surface numerical unit with the second smallest local safety factor; 13. Center point of numerical unit; 14. Starting point of potential sliding surface; 15. Last known potential sliding surface point; 16. Next unknown potential sliding surface point; 17. Sliding surface direction; 18. Sliding surface length; 19. Side of numerical unit; 20. Vertex on the side of numerical unit; 21. Potential sliding surface point to be determined; 22. Spatial geometric body; 23. Sliding surface point beyond the slope surface; 24. Potential sliding surface. DETAILED DESCRIPTION

[0050] In order to solve the above technical method problems, the present invention designs a method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations. The method obtains the slope stress field by carrying out numerical simulation calculations. Then, based on the shear strength criterion of rock and soil mass, the local safety factor of each numerical unit is solved by using the stress information of the numerical unit in the numerical model and the Mohr stress circle reflecting the stress state of the numerical unit, and the most unfavorable shear direction of each numerical unit is obtained. Then, the surface numerical unit of the slope is extracted from the numerical unit, and the surface numerical unit of the slope with the smallest local safety factor is taken as the boundary position of the potential sliding surface. Further, according to the positional relationship between the surface numerical units of the slope with the smallest and second smallest local safety factors, the identified boundary position of the potential sliding surface is clearly defined as the lower or upper boundary position of the potential sliding surface. Subsequently, starting from the center point of the surface numerical unit of the slope with the smallest local safety factor, the direction and position of the potential sliding surface are gradually identified in sections, and the corresponding potential sliding surface points are recorded in sequence. At the same time, it is judged whether the obtained potential sliding surface point exceeds the slope surface, and this is used as the termination basis for the identification of the direction and position of the potential sliding surface. Finally, the identified and extracted potential sliding surface points are connected in sequence to obtain a two-dimensional slope potential sliding surface.

[0051] The present invention has the characteristics of wide application range, high precision, good versatility, good effect, low cost, etc., and has automation and intelligent features. It can provide a strong scientific basis for predicting the potential instability range of slopes and determining reinforcement areas in actual projects.

[0052] The specific method and implementation process of the present invention are as follows:

[0053] (1) Figure 1 As shown in Figure 1, according to the actual slope shape, stratigraphic data and physical and mechanical parameters of rock and soil, a corresponding two-dimensional slope numerical model is established, and combined with numerical simulation software, numerical calculation is carried out to obtain the slope stress field and extract the information of each numerical unit in the two-dimensional slope numerical model, including number information, coordinate information (such as unit center coordinates and unit vertex coordinates) and stress information (such as major principal stress σ1, minor principal stress σ3 and normal stress σ along the vertical direction). z ), it should be noted that the two-dimensional slope numerical model is constructed based on the two-dimensional section of the three-dimensional slope stretched by a unit length in the thickness direction, and this unit length can be taken as 0.1m~1.0m.

[0054] (2) Figure 2 As shown in the figure, taking any numerical unit as an example, the numerical simulation is used to calculate the major principal stress σ1, minor principal stress σ3 and normal stress σ along the vertical direction of the numerical unit. z , draw the stress analysis diagram of the numerical unit, in which OA is the minor principal stress action surface, the force on it is the minor principal stress σ3, OB is the major principal stress action surface, the force on it is the major principal stress σ1, where the minor principal stress action surface OA and the major principal stress action surface OB are perpendicular to each other, OD is a horizontal plane, the force on it is the normal stress σ in the vertical direction z and shear stress τ xz , and the angle between OA and OD is α z , OT is the action surface in different directions in the numerical unit, and the angle between it and the action surface of the minor principal stress OA is α (0°≤α≤90°), and the forces acting on OT are the normal stress σ and the shear stress τ.

[0055] (3) Figure 2 As shown in the figure, based on the stress analysis of any numerical unit, the Mohr stress circle reflecting the stress state of the numerical unit is obtained, and the Mohr stress circle is drawn in the normal stress and shear stress rectangular coordinate system, which is consistent with the actual stress analysis diagram. In the Mohr stress circle, OA represents the action surface of the minor principal stress, OB represents the action surface of the major principal stress, OD represents the horizontal plane, and OT represents the action surface in different directions in the numerical unit, where O is the center point of the Mohr stress circle, point A and point B correspond to the minor principal stress σ3 and the major principal stress σ1 respectively, and the stress corresponding to point D is σ z and τ yz, the stresses corresponding to point T are σ and τ. Given that the angles in the Mohr stress circle model and the actual stress analysis model are twice as large, then in the Mohr stress circle, ∠AOD=2α z And ∠AOT=2α.

[0056] (4) Figure 2 As shown in the figure, based on the Mohr stress circle reflecting the stress state of the numerical unit, when α changes in the range of 0° to 90°, it can be known that the value range of the normal stress σ on the surface of the numerical unit in different directions is [σ3, σ1]. At the same time, in the Mohr stress circle, according to the spatial geometric relationship of the triangle OTE, it can be obtained that τ = [(σ1–σ)(σ–σ3)] 1 / 2 , where point E is the intersection of the vertical line through point T and the normal stress axis. In addition, the relationship between the normal stress σ and the angle α on the surface acting in different directions in the numerical unit satisfies σ=(σ3+σ1) / 2–[(σ1–σ3) / 2]cos2α.

[0057] (5) Figure 3 As shown in the figure, based on the selected rock and soil shear strength criterion, the numerical unit stress information is applied to calculate the local safety factor of each numerical unit in the numerical model, and determine the most unfavorable shear direction of each numerical unit. The specific implementation steps are as follows: ① Let the general expression of the rock and soil shear strength criterion be τ f =f(σ), where σ is the normal stress on the action surface, τ f is the shear strength on the action surface; ② Based on the Mohr stress circle reflecting the stress state of the numerical unit, the value range of the normal stress σ on the action surface in different directions in the numerical unit is determined to be [σ3, σ1], and the shear stress on the action surface in different directions under the corresponding normal stress in the numerical unit is obtained as τ = [(σ1–σ)(σ–σ3)] 1 / 2 ; ③ Combined with the shear strength criterion of rock and soil, the shear strength on the surface in different directions under the corresponding normal stress is calculated as τ f =f(σ); ④ According to the definition of safety factor, calculate the shear strength τ on the action surface f The ratio k of shear stress τ s , and k s =f(σ) / [(σ1–σ)(σ–σ3)] 1 / 2 ⑤ When the normal stress σ is in the interval [σ3, σ1], use the mathematical extreme value method to solve k s The minimum value of s ), which is the local safety factor F of the numerical unit s_Local , that is, F s_Local =min(k s );⑥The most unfavorable shear direction based on the numerical unit is k sThe direction of the action surface corresponding to the minimum value is taken. The relationship between the normal stress σ and the angle α on the action surface in different directions in the numerical unit is σ=(σ3+σ1) / 2–[(σ1–σ3) / 2]cos2α. The angle between the most unfavorable shear direction of the numerical unit and the direction of the small principal stress action surface is solved as α k =(1 / 2)×arcos{[(σ3+σ1)–2σ k ] / (σ1–σ3)}, where σ k k s The normal stress on the surface corresponding to the minimum value; ⑦ Further, using the relationship σ=(σ3+σ1) / 2–[(σ1–σ3) / 2]cos2α, the angle between the horizontal plane and the surface of the minor principal stress is solved as α z =(1 / 2)×arcos{[(σ3+σ1)–2σ z ] / (σ1–σ3)};⑧According to the angle between the most unfavorable shear direction of the numerical unit and the direction of the minor principal stress action surface and the angle between the horizontal plane and the minor principal stress action surface, the angle between the most unfavorable shear direction and the horizontal plane is deduced to be α critical =α z –α k , where α critical When it is greater than 0, the angle direction is counterclockwise, otherwise it is clockwise.

[0058] (6) Figure 4 As shown in the figure, in the numerical unit, there is a side surface belonging to a unique numerical unit, and the side surface is in the surface layer of the numerical model, so it is called the surface layer. The surface layer includes the slope surface and the boundary surface. Different from the slope surface coming from the natural form of the slope, the boundary surface is set artificially according to the needs of numerical analysis. That is to say, the boundary surface is self-defined and can be excluded from the surface layer according to the set boundary conditions. Here, the slope surface numerical unit is set as a numerical unit containing the slope surface. Then, the slope surface is extracted by obtaining the surface layer in the numerical model and excluding the boundary surface. Then, the slope surface numerical unit is determined according to the matching between the slope surface and the numerical unit. The specific implementation steps are as follows: ① Get the surface layer number and the surface group in the numerical model. For example, the numerical model divides the surface layer into six surface groups according to the direction of the outer normal of the surface layer, namely, the upper side, the lower side, the east side, the west side, the south side, and the north side. Among them, the boundary surface is divided into five surface groups, namely, the lower side, the east side, the west side, the south side, and the north side. Among them, the lower side in the surface group corresponds to Figure 4 The lower side of the numerical model corresponds to the middle side of the face group Figure 4 The back side of the numerical model, the west side of the face group corresponds to Figure 4 The front side of the numerical model, the south side of the face group corresponds to Figure 4 On the right side of the numerical model, the north side of the face group corresponds to Figure 4The left side of the numerical model; ② extract the nodes, node numbers and node coordinates contained in the surface layer; ③ exclude the boundary surface according to the artificially set boundary conditions. For example, when the xyz axis coordinate system is established with the horizontal direction in the two-dimensional slope plane as the x-axis direction, the two-dimensional slope thickness direction as the y-axis direction and the vertical direction as the z-axis direction, for the boundary surface of the lower side surface group, the node coordinates on the surface are all equal to the lower boundary coordinates z in the z-axis direction in the numerical model. below Based on this, when considering the calculation accuracy of the model, the z-axis coordinates of the nodes on the surface can be located at [z below –0.001, z below +0.001] interval is excluded from the surface layer. The boundary surfaces of the east, west, south, and north surface groups can be excluded from the surface layer in the same way. The coordinates of the front and rear boundaries in the x-axis direction in the numerical model are x front and x back , the left and right boundary coordinates of the y-axis direction in the numerical model are y left and right , the boundary coordinates in the z-axis direction in the numerical model are z above ; ④ Based on the number of the surface composed of the numerical unit, the numerical unit is traversed to determine whether the surface composed of the numerical unit belongs to the mid-slope surface of the surface layer, and then the numerical unit matching the mid-slope surface of the surface layer is found, and the surface numerical unit is further determined.

[0059] (7) Figure 5 As shown, among the numerical units on the slope surface, the numerical units on the slope surface are sorted from small to large according to the size relationship of the local safety factors of the numerical units, and the numerical unit on the slope surface with the smallest local safety factor is taken as the boundary position of the potential sliding surface. At the same time, the position relationship of the numerical units on the slope surface with the smallest and second smallest local safety factors in the sorting is compared. If the numerical unit on the slope surface with the smallest local safety factor is closer to the lower part of the slope than the numerical unit on the slope surface with the second smallest local safety factor, then the determined numerical unit on the slope surface is the boundary position of the lower edge of the potential sliding surface. Otherwise, if the numerical unit on the slope surface with the smallest local safety factor is closer to the upper part of the slope than the numerical unit on the slope surface with the second smallest local safety factor, then the determined numerical unit on the slope surface is the boundary position of the upper edge of the potential sliding surface.

[0060] (8) Figure 6As shown in the figure, the center point of the numerical unit of the slope surface with the smallest local safety factor is taken as the starting point of the potential sliding surface, and the direction and position of the potential sliding surface are gradually identified in sections, and the corresponding potential sliding surface points are recorded in sequence. Among them, the segmented step-by-step identification method is to discretize the potential sliding surface into multiple sections, and the length of each sliding surface is Δd, among which Δd should not be too large or too small. If it is too large, the potential sliding surface identification accuracy is not high, and if it is too small, the calculation efficiency is low. Usually, Δd can be taken as 0.1m~0.5m, and a low value is taken for small slopes and a high value is taken for large slopes. Then, using the last known potential sliding surface point, on the basis of determining the direction of this section of the sliding surface, the sliding surface length is extended along the direction of this section of the sliding surface by a length Δd, so as to solve the position of the next unknown potential sliding surface point, and continue in this way until the solved potential sliding surface point exceeds the slope surface.

[0061] (9) Figure 6 As shown in the figure, for each potential sliding surface trend, the determination principle is to take the most unfavorable shear direction of the numerical unit where the previous known potential sliding surface point is located in the sliding surface as the sliding surface trend of the segment. At the same time, considering the concave characteristics of the potential sliding surface, the potential sliding surface trend inclination should satisfy the constraint condition that increases from bottom to top. If it does not meet the constraint condition, the sliding surface trend of the segment will follow the previous sliding surface trend. Taking the determined slope surface numerical unit as the lower edge boundary position of the potential sliding surface as an example, the previous known potential sliding surface point of the unknown potential sliding surface point i is i–1, and the previous known potential sliding surface point of point i–1 is i–2, then α should be satisfied. i–1 ≥α i–2 , otherwise, if α i–1 <α i–2 , then let α i–1 =α i–2 , where α i–1 is the angle between the most unfavorable shear direction of the numerical unit where point i-1 is located and the horizontal plane direction, α i–2 It is the angle between the most unfavorable shear direction of the numerical unit where point i–2 is located and the horizontal plane direction.

[0062] (10) Figure 7As shown in the figure, in each sliding surface segment, the next unknown potential sliding surface point solved based on the previous known potential sliding surface point, the principle of determining the numerical unit in which it is located is to connect the potential sliding surface point to be determined with the vertex on the side surface of a certain numerical unit to form a spatial geometric body. At the same time, when connecting with the vertices on each side surface, multiple spatial geometric bodies will be obtained. If the sum of the volumes of these spatial geometric bodies is equal to the volume of the numerical unit, then this potential sliding surface point is located in the numerical unit. The specific implementation steps are as follows: ① Obtain the volume of the numerical unit and the side surface of the numerical unit and its vertex number and coordinates, and extract the side surface area of ​​the numerical unit and the coordinates of the center point; ② Select any 4 points from the vertices and center point on a side surface of the numerical unit , use the coordinates of these four points to determine the function of the side surface of this space, and then apply the distance calculation formula from the point to the spatial surface to solve the vertical distance from the potential sliding surface point to be determined to the side surface of the numerical unit; ③ Based on the obtained vertical distance from the potential sliding surface point to be determined to the side surface of the numerical unit and the side surface area of ​​the numerical unit, calculate the volume of the spatial geometric body formed by connecting the potential sliding surface point to be determined with the vertices on each side surface of the selected numerical unit and its sum; ④ traverse all numerical units, and determine whether the sum of the volumes of the spatial geometric bodies formed by connecting the potential sliding surface point to be determined with the vertices on each side surface of the selected numerical unit is equal to the volume of the numerical unit. If the two are equal, the numerical unit where the potential sliding surface point to be determined is located is obtained.

[0063] (11) Figure 8 As shown, when the direction and position of the potential sliding surface are gradually identified by segmentation, it is necessary to determine whether the next unknown potential sliding surface point solved is beyond the slope surface. The identification principle is that if the potential sliding surface point is a sliding surface point that exceeds the slope surface, then this potential sliding surface point will not be located on any numerical unit. Therefore, the specific method of determining the numerical unit where the potential sliding surface point to be determined is used to identify whether the potential sliding surface point is beyond the slope surface. That is, after traversing all numerical units, if the numerical unit where the potential sliding surface point is located cannot be determined, it can be considered that the potential sliding surface point is beyond the slope surface, and the identification of the direction and position of the potential sliding surface is stopped. Further, the obtained potential sliding surface points are connected in sequence to obtain a two-dimensional slope potential sliding surface.

[0064] (12) Fig. 9As shown in Figure 1, the implementation process of identifying and extracting the potential sliding surface of the slope in the two-dimensional numerical simulation calculation is as follows: ① Establish a two-dimensional slope numerical calculation model, carry out numerical calculations, and extract the information of each numerical unit in the numerical model; ② Calculate the local safety factor of each numerical unit in the numerical model, and obtain the angle between the most unfavorable shear direction and the horizontal plane direction of each numerical unit; ③ Determine the slope surface numerical unit with the smallest local safety factor, and based on the positional relationship between the slope surface numerical units with the smallest and second smallest local safety factors, determine whether the determined slope surface numerical unit is the lower edge boundary position of the potential sliding surface or the upper edge boundary position of the potential sliding surface; ④ Take the center point of the determined slope surface numerical unit as the starting point for potential sliding surface identification and extraction, and let the coordinates of the center point be (x0, z0); ⑤ Apply the segmented step-by-step identification method, based on the previous known potential sliding surface point i–1, solve the position of the next unknown potential sliding surface point i, the specific calculation formula is x i =x i–1 +Δd×cosα i–1 and z i =z i–1 +Δd×sinα i–1 , where (x i–1 , z i–1 ) is the coordinate of the last known potential sliding surface point i–1, (x i , z i ) is the coordinate of the next unknown potential sliding surface point, Δd is the length of the segmented sliding surface, α i–1 is the angle between the most unfavorable shear direction of the numerical unit where point i–1 is located and the horizontal plane direction. It should be noted that if the determined numerical unit of the slope surface is the boundary position of the lower edge of the potential sliding surface, Δd can be taken as a positive value, otherwise, Δd can be taken as a negative value; ⑥ Calculate the sum of the volumes of the spatial geometric bodies formed by connecting the potential sliding surface point i with the vertices on each side surface in each numerical unit, and determine the numerical unit where the potential sliding surface point i is located based on the sum of this volume being equal to the volume of a certain numerical unit; ⑦ According to whether the potential sliding surface point is located on a certain numerical unit, determine whether the potential sliding surface point i exceeds the slope surface. If the potential sliding surface point i exceeds the slope surface, stop identifying and extracting the potential sliding surface, otherwise, repeat steps ⑤ to ⑥; ⑧ Connect the identified and extracted potential sliding surface points in sequence to obtain the two-dimensional slope potential sliding surface.

[0065] The characteristics of the local safety factor solution of the present invention are: applying numerical simulation calculation technology to obtain the slope stress field, and on the basis of selecting the shear strength criterion of the rock and soil body, combining the stress information of the numerical unit in the numerical model and the Mohr stress circle reflecting the stress state of the numerical unit, the local safety factor of the numerical unit is solved. This method can utilize the powerful calculation function of the existing numerical simulation software and its favorable conditions for restoring the actual stress field of the slope in the real scene. At the same time, compared with the introduction of the strength reduction technology to solve the slope safety factor, the local safety factor solution does not change the real stress state of the slope. Moreover, when solving the local safety factor of the numerical unit, the most unfavorable shear direction of the numerical unit is also obtained. In addition, the local safety factor solution does not depend on the specific rock and soil shear strength criterion, which makes it have strong versatility.

[0066] The characteristics of the potential sliding surface identification and extraction of the present invention are: starting from the center point of the numerical unit of the slope surface with the smallest local safety factor, the direction and position of the potential sliding surface are gradually identified in sections, and whether the potential sliding surface point obtained exceeds the slope surface is used as the termination basis for the identification of the direction and position of the potential sliding surface. This method is conducive to the automation and intelligence of sliding surface identification and extraction. When the potential sliding surface is gradually identified in sections, the length of each sliding surface is controlled, which is easy to realize the refinement of potential sliding surface identification and extraction. The identified potential sliding surface points are completely matched with the numerical units in the numerical model, and the sliding surface direction is controlled by the most unfavorable shear direction of the numerical unit where the corresponding potential sliding surface point is located, which is in line with the shear failure mechanism of the slope. At the same time, the sliding surface direction is also controlled by the concave characteristics of the potential sliding surface, thereby ensuring the rationality of the identified and extracted potential sliding surface.

[0067] Example

[0068] A kind of Figures 1 to 9 The method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations is shown in the figure. The slopes along a highway are at great risk of collapse due to complex geological conditions and low rock and soil strength. In order to accurately predict the potential instability range of the slope and determine the reinforcement area, the method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations invented in this paper is introduced and applied. It successfully defines the potential range of slope collapse and effectively supports the implementation of reinforcement measures. The specific operations are as follows:

[0069] (1) According to the requirements of the Code for Geotechnical Engineering Investigation (GB50021-2001), the highway slope is surveyed and tested on the spot to obtain the two-dimensional slope surface shape (slope height H = 10m and slope angle β = 45°) and stratum data and corresponding rock and soil strength parameters in the analysis area. In this embodiment, the rock and soil of the slope is severely weathered and cracked and obeys the generalized nonlinear HB strength criterion. The specific strength parameters are GSI = 5, σ c =30MPa,m i=2 and D = 0; where GSI is the geological strength index, σ c is the uniaxial compressive strength of intact rock, m i is the material constant of intact rock, and D is the disturbance factor of the rock mass;

[0070] (2) According to the actual slope shape of the two-dimensional slope, a corresponding two-dimensional slope numerical model is established in the numerical simulation software, where the tensile unit length in the thickness direction is set to 0.1 m. At the same time, the corresponding rock and soil, layer parameters and their strength parameters are assigned, and the corresponding model boundary constraints are set;

[0071] (3) Carry out numerical calculations and extract the information of each numerical unit in the numerical model, including number information, coordinate information (such as unit center coordinates and unit vertex coordinates), and stress information (such as major principal stress σ1, minor principal stress σ3, and normal stress σ along the vertical direction). z );

[0072] (4) Calculate the local safety factor F of each numerical unit in the numerical model s_Local , where the calculation formula for the shear strength of rock and soil under the generalized nonlinear HB strength criterion is: Parameter m b , s, α and The calculation formulas are α = 0.5 + (1 / 6) × [exp(–GSI / 15) – exp(–20 / 3)] and Among them, m b is a material constant, s is a parameter reflecting the degree of rock mass fragmentation, and α is a constant related to the rock mass structure and surface conditions. is the instantaneous internal friction angle of the rock mass;

[0073] (5) Calculate the most unfavorable shear direction of each numerical unit and the angle α between the most unfavorable shear direction and the horizontal plane direction critical ;

[0074] (6) Obtain the surface level of the slope numerical model using the software FLAC 3D The commands “gp.isgroup()” and “gp.pos()” extract the nodes, node numbers and node coordinates contained in each surface layer. Then, all non-surface layers are excluded according to the node coordinate characteristics of the non-surface layers, and the surface layer of the actual slope is obtained.

[0075] (7) Identify and extract the numerical units of the slope surface layer to which the surface layer belongs, traverse the units, and use the software FLAC 3D The command “zone.face.isgroup()” identifies and extracts all the slope surface numerical units corresponding to the surface layer.

[0076] (8) Determine the potential sliding surface boundary position. In the numerical units on the slope surface, sort the numerical units on the slope surface from small to large according to the size relationship of the local safety factors of the numerical units, and take the numerical unit on the slope surface with the smallest local safety factor as the potential sliding surface boundary position. For this slope numerical model, the numerical unit on the slope surface with the smallest local safety factor is closer to the lower part of the slope than the numerical unit on the slope surface with the second smallest local safety factor. Therefore, the numerical unit on the slope surface with the smallest local safety factor is determined to be the lower edge boundary position of the potential sliding surface.

[0077] (9) Calculate the discrete points of the potential sliding surface. Take the center point of the slope surface numerical unit with the smallest local safety factor as the starting point of the potential sliding surface, and extract its coordinates (x0, z0). Then, extend it upward along its sliding trend. Each extension length is Δd, where Δd is taken as 0.3m. Then, apply the segmented step-by-step identification method. Based on the previous known potential sliding surface point i–1, solve the position of the next unknown potential sliding surface point i. The specific calculation formula is x i =x i–1 +Δd×cosα i–1 and z i =z i–1 +Δd×sinα i–1 , where α i–1 is the angle between the most unfavorable shear direction of the numerical unit where point i–1 is located and the horizontal plane direction; at the same time, in order to satisfy the concave characteristics of the sliding surface, α i–1 Should satisfy α i–1 ≥α i–2 , otherwise, if α i–1 <α i–2 , then let α i–1 =α i–2 ;

[0078] (10) Determine the numerical unit where the potential sliding surface point i is located and whether it exceeds the slope surface. For each potential sliding surface point i, the sum of the volumes of the spatial geometric body formed by connecting the potential sliding surface point i with the vertices on each side surface in each numerical unit needs to be calculated. The numerical unit where the potential sliding surface point i is located is determined based on the sum of the volumes being equal to the volume of a certain numerical unit. When the potential sliding surface point is not located in any numerical unit, it means that this point has exceeded the slope surface, and the identification and extraction of the potential sliding surface point is stopped. Then, the identified and extracted potential sliding surface points are connected in sequence to obtain the two-dimensional potential sliding surface of the slope. The characteristics of the two-dimensional potential sliding surface of the slope obtained in this embodiment are that the sliding range extends from 0.5m to 13.5m from the slope foot, the maximum sliding depth is 3.4m, and the sliding range area is 36.9m 2 .

[0079] In general, the present invention relates to a method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations, and belongs to the field of traffic slope engineering. According to the positional relationship between the numerical units of the slope surface with the smallest and second smallest local safety factors, the identified potential sliding surface boundary position is clearly defined as the lower or upper edge boundary position of the potential sliding surface; finally, the identified and extracted potential sliding surface points are sequentially connected to obtain the two-dimensional potential sliding surface of the slope. The present invention does not need to introduce strength reduction technology and does not limit the shear strength criterion of the rock and soil body. It can automatically and intelligently identify and extract the potential sliding surface of the two-dimensional slope. The obtained potential sliding surface conforms to the shear failure mechanism of the slope and can effectively show the actual failure form of the two-dimensional slope in the real scene; it has the characteristics of wide application range, high precision, good versatility, good effect, low cost, etc., and is used to solve the problem of accurate determination of potential sliding surfaces in actual slope engineering, and can provide a strong scientific basis for the prediction of the potential instability range of the slope and the determination of the reinforcement area in actual engineering.

[0080] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations, characterized in that: The method comprises the following steps: Step S1: Establish a two-dimensional slope numerical calculation model, carry out numerical calculation, and extract information of each numerical unit in the numerical model; Step S2: Calculate the local safety factor of each numerical unit in the numerical model, and obtain the angle α between the most unfavorable shear direction of each numerical unit and the horizontal plane direction critical ; Step S3: determining the slope surface numerical unit with the smallest local safety factor, and judging whether the determined slope surface numerical unit is the lower edge boundary position of the potential sliding surface or the upper edge boundary position of the potential sliding surface based on the positional relationship between the slope surface numerical unit with the smallest local safety factor and the slope surface numerical unit with the second smallest local safety factor; Step S4: taking the center point of the determined slope surface numerical unit as the starting point for potential sliding surface identification and extraction, and setting the coordinates of the center point to (x0, z0); Step S5: Apply the segmented step-by-step identification method to solve the position of the next unknown potential sliding surface point i based on the previous known potential sliding surface point i–1. The specific calculation formula is x i =x i–1 +Δd×cosα i–1 and z i =z i–1 +Δd×sinα i–1 ; Among them, α i–1 is the angle between the most unfavorable shear direction of the numerical unit where point i–1 is located and the horizontal plane direction; and if the determined numerical unit of the slope surface is the lower edge boundary position of the potential sliding surface, Δd is taken as a positive value; otherwise, Δd is taken as a negative value; Among them, (x i–1 , z i–1 ) is the coordinate of the last known potential sliding surface point i–1, (x i , z i ) is the coordinate of the next unknown potential sliding surface point, Δd is the length of the segmented sliding surface, α i–1 is the angle between the most unfavorable shear direction of the numerical unit where point i–1 is located and the horizontal plane direction; Step S6: Calculate the sum of the volumes of the spatial geometric bodies formed by the potential sliding surface point i and the vertices on each side surface in each numerical unit, and determine the numerical unit where the potential sliding surface point i is located based on the sum of the volumes being equal to the volume of a certain numerical unit; Step S7: judging whether the potential sliding surface point i exceeds the slope surface according to whether the potential sliding surface point is located on a certain numerical unit; if the potential sliding surface point i exceeds the slope surface, the identification and extraction of the potential sliding surface is stopped; otherwise, repeating steps S5 to S6; Step S8: sequentially connect the identified and extracted potential sliding surface points to obtain a two-dimensional potential sliding surface of the slope.

2. The method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations according to claim 1 is characterized in that: Step S2 specifically includes the following steps: Step S2-1: Let the general expression of the shear strength criterion of rock and soil be τ f =f(σ), where σ is the normal stress on the action surface, τ f is the shear strength on the action surface; Step S2-2: Based on the Mohr stress circle reflecting the stress state of the numerical unit, determine the value range of the normal stress σ on the surface acting in different directions in the numerical unit as [σ3, σ1], and obtain the shear stress on the surface acting in different directions under the corresponding normal stress in the numerical unit as τ = [(σ1–σ)(σ–σ3)] 1 / 2 ; Among them, σ3 is the minor principal stress of the numerical unit, and σ1 is the major principal stress of the numerical unit; Step S2-3: Combined with the shear strength criterion of rock and soil, the shear strength on the surface in different directions under the corresponding normal stress is calculated as τ f =f(σ); Step S2-4: Calculate the shear strength τ on the action surface according to the safety factor definition f The ratio k of shear stress τ s , and k s =f(σ) / [(σ1–σ)(σ–σ3)] 1 / 2 ; Step S2-5: When the normal stress σ is in the interval [σ3, σ1], use the mathematical extreme value method to solve k s The minimum value of s ), which is the local safety factor F of the numerical unit s_Local , that is, F s_Local =min(k s ); Step S2-6: The most unfavorable shear direction based on the numerical unit is k s The direction of the action surface corresponding to the minimum value is taken. The relationship between the normal stress σ and the angle α on the action surface in different directions in the numerical unit is σ=(σ3+σ1) / 2–[(σ1–σ3) / 2]cos2α. The angle between the most unfavorable shear direction of the numerical unit and the direction of the small principal stress action surface is solved as α k =(1 / 2)×arcos{[(σ3+σ1)–2σ k ] / (σ1–σ3)}, where σ k k s The normal stress on the corresponding action surface when the minimum value is taken; Step S2-7: Using the relationship σ=(σ3+σ1) / 2–[(σ1–σ3) / 2]cos2α, solve for the angle α between the horizontal plane and the minor principal stress action surface z =(1 / 2)×arcos{[(σ3+σ1)–2σ z ] / (σ1–σ3)}; σ z is the normal stress of the numerical unit along the vertical direction; Step S2-8: Based on the angle between the most unfavorable shear direction of the numerical unit and the direction of the minor principal stress action surface and the angle between the horizontal plane and the minor principal stress action surface, the angle between the most unfavorable shear direction and the horizontal plane is deduced to be α critical =α z –α k , where α critical When it is greater than 0, the angle direction is counterclockwise, otherwise it is clockwise.

3. The method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations according to claim 1 is characterized in that: The slope meets the generalized nonlinear HB strength criterion, and in step S2, the shear strength calculation formula of the rock and soil mass is: Among them, m b is a material constant, s is a parameter reflecting the degree of rock mass fragmentation, and α is a constant related to the rock mass structure and surface conditions. is the instantaneous internal friction angle of the rock mass.

4. The method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations according to claim 3 is characterized in that: In step S2, parameter m b , s, α and The calculation formulas are: α=0.5+(1 / 6)×[exp(–GSI / 15)–exp(–20 / 3)] Among them, GSI is the geological strength index, σ c is the uniaxial compressive strength of intact rock, m i is the material constant of intact rock, and D is the disturbance factor of the rock mass.

5. The method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations according to claim 4 is characterized in that: In step S5, after extracting the coordinates (x0, z0) of the center point, it is extended upward along its sliding trend, and each extension length is Δd, where Δd is taken as 0.1-0.5m, and then the segmented step-by-step identification method is applied to solve the position of the next unknown potential sliding surface point i based on the previous known potential sliding surface point i-1; and in order to meet the concave characteristics of the sliding surface, α i–1 Should satisfy α i–1 ≥α i–2 Otherwise, if α i–1 <α i–2 , then let α i–1 =α i–2 .

6. The method for identifying and extracting potential sliding surfaces of slopes in two-dimensional numerical simulation calculations according to any one of claims 1 to 5, characterized in that: Using FLAC software 3D Conduct numerical simulation analysis.

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