A block stability analysis method within the framework of continuum numerical analysis

Abstract

The present invention provides a block stability analysis method within a continuum numerical analysis framework, comprising the following steps: S1, establishing a numerical analysis model; S2, separating the continuous grid; S3, reconstraining the separated grid; S4, applying initial constraints; S5, applying initial stress; S6, obtaining the initial stable state of the block; S7, analyzing the block safety factor; and S8, determining the block safety factor after support. This analysis method overcomes the limitations of traditional block stability analysis, which relies on theoretical and discontinuous analysis methods, and enriches the technical means of block stability analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of surrounding rock stability of underground caverns and slope engineering, and in particular to a block stability analysis method under a continuous medium numerical analysis framework. Background Art

[0002] Rock mass is a distinctly heterogeneous material, and one of the most obvious manifestations of its heterogeneity is the various structural surfaces within it. After excavation of underground caverns and slopes, the structural surfaces within the rock mass combine with the excavation's free-facing surfaces, potentially cutting into independent blocks. Once these independent blocks are formed on the excavation surfaces of underground caverns and slopes, they pose a risk of instability, posing a significant challenge to the stability of the surrounding rock mass. Larger blocks can even pose a threat to personnel safety. Therefore, block stability analysis is essential in the design and construction of large-scale underground caverns and slopes, and is a key issue concerning the stability of the surrounding rock mass. Block stability analysis can provide sufficient support for block support design, ensuring the safety of underground caverns and slopes.

[0003] Currently, block stability analysis methods are primarily based on theoretical approaches such as block theory or non-continuum mechanics methods such as discrete element methods. While traditional continuum numerical analysis methods such as finite element and finite difference methods are the most widely used in factories, they are rarely used for block stability analysis due to their inherent continuity assumptions. Summary of the Invention

[0004] The present invention provides a block stability analysis method under the framework of continuous medium numerical analysis, which overcomes the limitations of traditional block stability analysis that requires the use of theoretical methods and discontinuous analysis methods, and enriches the technical means of block stability analysis.

[0005] In order to achieve the above technical features, the purpose of the present invention is achieved as follows: a block stability analysis method under a continuous medium numerical analysis framework comprises the following steps:

[0006] S1, numerical analysis model establishment:

[0007] A three-dimensional numerical analysis model of the block is established. In the framework of continuous medium numerical analysis, this numerical analysis model is a continuous grid; the numerical analysis model includes the boundaries of the structural surfaces that constitute the block;

[0008] S2, continuous grid separation:

[0009] Decompose each node distributed on the block boundary into two nodes;

[0010] S3, separate the grid and then constrain it:

[0011] Introduce a rod element with dual constraints of tension, compression and shear at the boundary of the block structure surface to re-constrain the boundary of the structure surface;

[0012] S4, initial constraint application:

[0013] No constraints are imposed on the free surface of the block, and boundary normal constraints are imposed on other boundaries;

[0014] S5, initial stress application:

[0015] Based on the original rock stress state of the block, the stress state of each unit in the calculation model is assigned an initial value and calculated until convergence. Then, the cavern area is excavated to obtain the redistributed stress state after the cavern excavation, which is used as the initial stress state for block analysis.

[0016] S6, obtain the initial stable state of the block:

[0017] Based on step S5, the strength parameters of the member unit are converted into actual strength parameters, and calculation analysis is carried out. There are two cases for the final calculation results;

[0018] S7, block safety factor analysis:

[0019] On the basis of step S6, the strength parameters of the block structural surface are gradually reduced in equal proportion, and the strength parameters corresponding to the structural surface member elements are adjusted;

[0020] S8, Determination of block safety factor after support:

[0021] If the safety factor of the block obtained in step S7 does not meet the safety factor requirements specified in the specification, support measures need to be provided to stabilize the block.

[0022] Preferably, the numerical analysis model in S1 must have at least two structural surfaces to constitute a block; including the free surface of the block; including the surrounding rock outside the block, and the surrounding rock range is at least 3 to 5 times the range outside the block.

[0023] Preferably, after the continuous grid nodes are decomposed at the block boundary in S2, the model at this time exhibits discontinuous features at the block boundary, and there is no interaction at all on both sides of the block structure surface.

[0024] Preferably, the rod units in S3 are distributed at the grid centroids on both sides of each block structural surface, and the length of the rod is based on just passing through the grids on both sides of the structural surface; based on the characteristic that the rod unit just passes through the grid centroids on both sides of the structural surface, the equivalent control area of ​​each rod unit is the area of ​​the surface grid it passes through; the tensile strength parameter and shear strength parameter of the rod unit are the structural surface strength parameter multiplied by the equivalent control area of ​​the rod unit.

[0025] Preferably, the normal mechanical properties of the rod element in S3 are:

[0026] ;

[0027] Where, is the normal stiffness of the member unit, and its value is 10~1000 times the deformation modulus of the surrounding rock; is the equivalent control area of ​​the bar element; is the unit normal deformation of the member, positive indicates expansion deformation, negative indicates compression deformation; represents the normal force of the bar element, Indicates the maximum normal force that can be achieved by the member element;

[0028] Tangential mechanical properties of rod elements:

[0029] ;

[0030] Where, is the tangential stiffness of the member unit, and its value is 10~1000 times the deformation modulus of the surrounding rock; is the unit tangential deformation of the member, represents the tangential force of the member element, and Indicates the maximum tangential force that the member element can achieve in two tangential directions;

[0031] The tensile strength and shear strength of the bar element are:

[0032] ;

[0033] ;

[0034] in, is the tensile strength of the block structure surface, is the cohesion of the block structure surface, is the friction angle of the block structural surface; for block analysis problems, these parameters can be obtained from geological survey data.

[0035] Preferably, during the calculation process in S5, the strength parameter of the rod element is assigned a maximum value to ensure that the rod element is in an elastic working state during the initial stress application process.

[0036] Preferably, the two situations in S6 specifically include:

[0037] The first one is that the calculation finally converges, indicating that the block is currently in a stable state; the second one is that the calculation finally does not converge, indicating that the block is currently unstable.

[0038] Preferably, the strength reduction in S7 is expressed by the following formula:

[0039] ;

[0040] ;

[0041] ;

[0042] Where, is the strength reduction factor, for the initial stable block, Gradually increase from 1.0 until the calculation does not converge, for the initial unstable block, Gradually decrease from 1.0 until the calculation begins to converge;

[0043] The safety factor of the block is the critical state of block instability obtained by strength reduction. The critical state of block instability is determined by the relationship curve between the displacement of the block characteristic point and the strength reduction coefficient. The critical point is characterized by a sudden increase in the slope of the curve, a sharp increase in deformation, and non-convergence of the calculation.

[0044] Preferably, in said S8, the support force is applied to the free surface of the block in the form of surface force, and then the safety factor of the block after the support force is applied is further analyzed using the method shown in step S7 until the support force makes the safety factor of the block meet the requirements of the specification.

[0045] Beneficial effects of the present invention:

[0046] 1. The present invention proposes a method for performing block stability analysis within the framework of continuous medium numerical analysis, which overcomes the limitations of traditional block stability analysis that requires the use of theoretical methods and discontinuous analysis methods, and enriches the technical means of block stability analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be further described below with reference to the accompanying drawings and examples.

[0048] Figure 1 A schematic flow chart of a method according to an embodiment of the present invention.

[0049] Figure 2 Block structural surface information according to an embodiment of the present invention.

[0050] Figure 3 The overall numerical analysis model of the embodiment of the present invention.

[0051] Figure 4 The block morphology of the numerical analysis model of the embodiment of the present invention.

[0052] Figure 5 Schematic diagram of grid separation according to an embodiment of the present invention.

[0053] Figure 6 Schematic diagram of separate mesh reconstraint according to an embodiment of the present invention.

[0054] Figure 7 A partially enlarged schematic diagram of the separation grid re-constraint according to an embodiment of the present invention.

[0055] Figure 8 Schematic diagram of initial constraint application according to an embodiment of the present invention.

[0056] Figure 9 Initial stress state of an embodiment of the present invention (unit: Pa).

[0057] Figure 10 Strength reduction curve after support according to an embodiment of the present invention.

[0058] Figure 11 (a) (b) are the normal and tangential mechanical properties of the rod element. DETAILED DESCRIPTION

[0059] To more clearly illustrate the technical solutions of the embodiments of this specification, the following briefly describes the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this specification. Those skilled in the art can apply this specification to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0060] Example 1:

[0061] The present invention provides a block stability analysis method under a continuous medium numerical analysis framework, comprising the following steps:

[0062] S1, numerical analysis model establishment:

[0063] A three-dimensional numerical analysis model of the block is established. In the framework of continuous medium numerical analysis, this numerical analysis model is a continuous grid; the numerical analysis model includes the boundaries of the structural surfaces that constitute the block; generally, at least two structural surfaces are required to constitute a block; the free surface of the block is included; and the surrounding rock outside the block is included, with the surrounding rock range being at least 3 to 5 times the range outside the block.

[0064] S2, continuous grid separation:

[0065] Each node distributed on the block boundary is decomposed into two nodes. After decomposing the continuous mesh nodes at the block boundary, the model now exhibits discontinuous characteristics at the block boundary, that is, there is no interaction between the two sides of the block structure surface.

[0066] S3, separate the grid and then constrain it:

[0067] At the boundary of the block structure surface, rod elements with dual constraints of tension, compression and shear are introduced to re-constrain the boundary of the structure surface; the rod elements can be distributed at the centroids of the meshes on both sides of each block structure surface, and the length of the rod is based on just passing through the meshes on both sides of the structure surface. Since the rod element just passes through the centroids of the meshes on both sides of the structure surface, the equivalent control area of ​​each rod element is the mesh area of ​​the surface it passes through; the tensile strength parameter and shear strength parameter of the rod element are the structural surface strength parameter multiplied by the equivalent control area of ​​the rod element. The mechanical properties of the rod element are as follows Figure 11 As shown in (a) and (b).

[0068] Normal mechanical properties of rod elements:

[0069] ;

[0070] Where, is the normal stiffness of the member unit, and its value is 10~1000 times the deformation modulus of the surrounding rock; is the equivalent control area of ​​the bar element; is the unit normal deformation of the member, positive indicates expansion deformation, negative indicates compression deformation; represents the normal force of the bar element, Indicates the maximum normal force that can be achieved by the member element;

[0071] Tangential mechanical properties of rod elements:

[0072] ;

[0073] Where, is the tangential stiffness of the member unit, and its value is 10~1000 times the deformation modulus of the surrounding rock; is the unit tangential deformation of the member, represents the tangential force of the member element, and Indicates the maximum tangential force that the member element can achieve in two tangential directions;

[0074] The tensile strength and shear strength of the bar element are:

[0075] ;

[0076] ;

[0077] in, is the tensile strength of the block structure surface, is the cohesion of the block structure surface, is the friction angle of the block structure surface; for block analysis problems, these parameters can be obtained from geological survey data;

[0078] S4, initial constraint application:

[0079] No constraints are imposed on the free surface of the block, and boundary normal constraints are imposed on other boundaries;

[0080] S5, initial stress application:

[0081] Based on the original rock stress state of the block, the stress state of each unit in the calculation model is assigned an initial value and calculated to a convergent state; then, the cavern area is excavated to obtain the stress state after redistribution, which is used as the initial stress state for block analysis; during the calculation process, the strength parameter of the rod unit can be assigned a maximum value to ensure that the rod unit is in an elastic working state during the initial stress application process.

[0082] S6, obtain the initial stable state of the block:

[0083] Based on step S5, the strength parameters of the rod element are converted into actual strength parameters, and calculation analysis is carried out. There are two situations for the final calculation results: the first is that the calculation finally converges, indicating that the block is currently in a stable state; the second is that the calculation does not finally converge, indicating that the block is currently unstable.

[0084] S7, block safety factor analysis:

[0085] On the basis of step S6, the strength parameters of the block structural surface are gradually reduced in equal proportion, and the strength parameters corresponding to the structural surface member elements are adjusted;

[0086] Strength reduction is expressed by the following formula:

[0087] ;

[0088] ;

[0089] ;

[0090] Where, is the strength reduction factor, for the initial stable block, Gradually increase from 1.0 until the calculation does not converge, for the initial unstable block, Gradually decrease from 1.0 until the calculation begins to converge;

[0091] The safety factor of the block is the critical state of block instability obtained by strength reduction. The critical state of block instability is determined by the relationship curve between the displacement of the block characteristic point and the strength reduction coefficient. The critical point is characterized by a sudden increase in the slope of the curve, a sharp increase in deformation, and non-convergence of the calculation.

[0092] S8, Determination of block safety factor after support:

[0093] If the block safety factor obtained in step S7 does not meet the safety factor requirements specified in the code, support measures must be provided to stabilize the block. The support force is applied to the free surface of the block in the form of a surface force. The block safety factor after the support force is applied is then further analyzed using the method shown in step S7 until the support force ensures that the block safety factor meets the code requirements.

[0094] Example 2:

[0095] like Figure 1 As shown, an embodiment of the present invention provides a block stability analysis method under a continuous medium numerical analysis framework, comprising the following steps:

[0096] Step S1: Establish a three-dimensional continuous numerical model including the boundary morphology of the block structure surface to be analyzed.

[0097] For ease of description, the embodiments of the present invention are described below using an example of an underground powerhouse block of a hydropower station.

[0098] The structural surface cataloging information during the construction period of the downstream side wall of a power station's main building shows the existence of a block. This block is composed of three structural surfaces and the main building excavation face. The three structural surfaces have the following attitudes: fissure J1, EW / S∠55°~75°; fissure J5-1, N60~90°E / SE∠10~30°; fault fCF-2, N45°~55°E / SE∠85°, as shown in Figure 1. Figure 2 shown.

[0099] First, a three-dimensional continuous numerical model for the stability analysis of the block was established. Figure 3 The model includes the excavation cavern shape and the block structure surface boundary shape, as shown in Figure 4 As shown; and the outside of the block is close to the surrounding rock, and the surrounding rock range is more than 3 times the size of the block and the cavern.

[0100] Step S2: For the continuous grid model of block stability analysis, separation processing is performed at the boundary of the structural surface.

[0101] For the block stability analysis example shown, the block and the surrounding rock are separated from the original common node connection state of the continuous grid to the non-common node separation state of the discontinuous grid, as shown in Figure 5 At this point, the block of the embodiment of the present invention is completely disconnected from the surrounding rock.

[0102] Step S3: For the separated block stability analysis, separate the mesh model and use rod elements to re-constrain the structural surface boundary.

[0103] For the block stability analysis example shown, the block, surrounding rock, and cavern are all divided into tetrahedral meshes, that is, the structural surface between the block and the surrounding rock is discretized into triangular surface meshes. Although, after implementing step S2, the block and the surrounding rock are separated at the boundary of the structural surface, that is, one triangular surface mesh is separated into two; but the node positions and centroid positions of the triangular surface mesh on the block side of the structural surface are the same as those on the surrounding rock side. Figure 6 and Figure 7 According to step S3, a rod element is inserted at the block structure surface. The rod element is based on just passing through the triangular surface mesh. The rod element can be inserted at the centroid of each triangular surface mesh.

[0104] According to the geological data of the power station, the deformation modulus of the rock mass in the underground powerhouse area is 22.5GPa, the Poisson's ratio is 0.2, and the density is 2650kg / m 3 The cohesion c of fault fCF-2 is 0.1MPa and the friction angle is is 26.56°, the cohesion c of cracks J1 and J5-1 is 0.15 MPa, and the friction angle 35°. Use the mechanical properties of the rod element in step S3 to set the normal stiffness of the rod element. and tangential stiffness The values ​​are 100 times the deformation modulus of the rock mass, i.e. 2250 GPa. The cohesion c of the upper rod element of J1 and J5-1 is set to 0.15 MPa, and the friction angle is set to is 35°, and the cohesion c of the upper rod element of fCF-2 is set to 0.1 MPa and the friction angle is 26.56°; when analyzing the block, follow the code and set the tensile strength of the bar element at each part of J1, J5-1, and fCF-2 All are set to 0, that is, the effect of tensile strength of the structural surface is not considered. In addition, for the rock mass area, elastic materials are used, according to the rock mass deformation modulus of 22.5GPa, Poisson's ratio of 0.2, and density of 2650kg / m 3 Assign material parameters.

[0105] Step S4: Apply initial constraints. No constraints are applied to the free surface of the block, and boundary normal constraints are applied to other boundaries.

[0106] In this embodiment, step S3 has assigned material parameters to each part of the block stability analysis model. Before starting the simulation, the model boundary conditions need to be determined. Since the model boundary is larger than the cavity and block size by more than 3 times, it has exceeded the block influence range. Normal fixed constraints can be applied to the side and bottom boundaries of the model, such as Figure 8 shown.

[0107] Step S5: Apply the initial stress state. Based on the in-situ rock stress state of the block, the stress state of each element in the computational model is assigned an initial value and calculated until convergence. Then, the cavern area is excavated to obtain the redistributed stress state after excavation. During the calculation process, the strength parameters of the member elements are assigned a maximum value to ensure that the member elements are in an elastic working state during the initial stress application process.

[0108] In step S4, normal constraints are applied to the side and bottom boundaries of the calculation model. For the top boundary of the calculation model, a normal load can be applied according to the magnitude of the self-weight stress in the cavern area. Specifically, according to engineering geological data, the self-weight stress in the cavern area of ​​this embodiment is about 18MPa; and the actual model is not established to the actual surface elevation within the elevation range, and it is difficult to automatically generate the self-weight stress field through the self-weight of the material. Therefore, a uniformly distributed pressure load of 18MPa is applied to the upper surface of the model to represent the self-weight pressure of the rock mass outside the model range. Then, the strength parameters of each rod unit are given a maximum value, that is, the cohesion c of the rod unit at each part of J1, J5-1, and fCF-2 is set to 100GPa, and the friction angle is set to 100GPa. Set to 89.9°, tensile strength Set to 100GPa; on this basis, the self-weight stress field can be generated by solving.

[0109] Based on engineering geological data, the horizontal geostress lateral pressure coefficient for this example is approximately 1.1 in the direction perpendicular to the sidewalls, and approximately 1.54 in the direction of the cavern axis. Based on the self-weight stress field obtained, the stress components in the model region perpendicular to the sidewalls and along the cavern axis are respectively set equal to the self-weight stress multiplied by the corresponding geostress lateral pressure coefficient. After the calculation converges, the complete in-situ rock stress field in the cavern region is obtained.

[0110] Since the surrounding rock stress field will be redistributed after the underground cavern excavation, the redistributed stress field may also affect the stability of the block. Based on the above-mentioned original rock stress field, the cavern area simulation excavation is carried out. After the calculation is converged, the stress field information of the surrounding rock after the cavern excavation is obtained, such as Figure 9 shown.

[0111] Step S6: Obtain the initial stable state of the block. Based on the above, the strength parameters of the member elements are converted to actual strength parameters, and calculations and analysis are performed. The final results can be in two scenarios: First, the calculations converge, indicating that the block is currently stable; second, the calculations do not converge, indicating that the block is currently unstable.

[0112] In this embodiment, based on step S5, the block boundary member elements are adjusted again to the member element parameters established in step S3. Then, a direct solution is obtained. If the solution fails to converge, it indicates that the initial state of the block is not self-stable, that is, the block is initially unstable.

[0113] Step S7: Determine the initial safety factor of the block. Based on step S6, the strength parameters of the block structure surface are gradually reduced in equal proportion, and the strength parameters corresponding to the structure surface member elements are adjusted. The strength reduction can be expressed by the following formula.

[0114] In this embodiment, since step S6 determines that the block is an initially unstable block, when determining the initial safety factor of the block, it is necessary to continuously reduce value, carry out strength reduction analysis; according to gradually reduce After the block structure surface is completed, the bar unit parameters are calculated and analyzed respectively until the calculation results converge. Based on the strength reduction analysis of the above steps, when =0.59, the calculation converges, indicating that the initial safety factor of the block is 0.59.

[0115] Step S8: Determine the block safety factor after support. If the block safety factor obtained in S7 does not meet the safety factor requirements specified in the code, support measures are required to stabilize the block. The support force can be applied to the free surface of the block in the form of a surface force. The block safety factor after the support force is applied can then be further analyzed using the method shown in S7 until the support force ensures that the block safety factor meets the code requirements.

[0116] For this embodiment, based on step S7, it is determined that the initial safety factor of the block is 0.59, which is less than the safety factor required by the specification. Support measures need to be provided for the block so that its safety factor meets the requirements of the specification. According to the block support measures provided by the cavern, a support force of 200kN can be provided for the block. The 200kN support force is applied to the free surface of the block as a uniform surface force. At this time, the calculation can converge. By repeating the strength reduction analysis of step S7, the relationship between the block displacement and the safety factor during the strength reduction process can be obtained, that is, Figure 10 The strength reduction process curve shown in Figure 2 is shown in Figure 2. According to the relationship curve, when the safety factor is When the safety factor is less than 3.5, the block displacement increases but the increase is small and the slope of the curve does not change significantly. When it is greater than 3.5, the block displacement growth rate increases and the slope of the curve increases; The calculation does not converge when it is 3.8. Therefore, the safety factor of the block after support is determined to be 3.5, that is, under the support force of 200kN, the block has a safety factor of 3.5.

[0117] Finally, it should be understood that the embodiments described in this specification are intended only to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly described and illustrated in this specification.

Claims

1. A block stability analysis method under the framework of continuous medium numerical analysis, characterized in that: The following steps are involved: S1, numerical analysis model establishment: A three-dimensional numerical analysis model of the block is established. In the framework of continuous medium numerical analysis, this numerical analysis model is a continuous grid; the numerical analysis model includes the boundaries of the structural surfaces that constitute the block; S2, continuous grid separation: Decompose each node distributed on the block boundary into two nodes; S3, separate the grid and then constrain it: Introduce a rod element with dual constraints of tension, compression and shear at the boundary of the block structure surface to re-constrain the boundary of the structure surface; S4, initial constraint application: No constraints are imposed on the free surface of the block, and boundary normal constraints are imposed on other boundaries; S5, initial stress application: Based on the original rock stress state of the block, the stress state of each unit in the calculation model is assigned an initial value and calculated to a convergent state; Then, the cavern area is excavated to obtain the stress state after redistribution after cavern excavation, which is used as the initial stress state for block analysis; S6, obtain the initial stable state of the block: Based on step S5, the strength parameters of the member element are converted into actual strength parameters, and calculation analysis is carried out. The final calculation results have two situations: convergence and non-convergence; S7, block safety factor analysis: On the basis of step S6, the strength parameters of the block structural surface are gradually reduced in equal proportion, and the strength parameters corresponding to the structural surface member elements are adjusted; S8, Determination of block safety factor after support: If the safety factor of the block obtained in step S7 does not meet the safety factor requirements specified in the specification, support measures need to be provided to stabilize the block.

2. The block stability analysis method under the continuum numerical analysis framework according to claim 1 is characterized in that: The numerical analysis model in S1 must have at least two structural surfaces to constitute a block; it includes the free surface of the block; it includes the surrounding rock outside the block, and the surrounding rock range is at least 3 to 5 times the range outside the block.

3. The block stability analysis method under the continuum numerical analysis framework according to claim 1 is characterized in that: After the continuous grid nodes are decomposed at the block boundary in S2, the model at this time exhibits discontinuous features at the block boundary, and there is no interaction at all on both sides of the block structure surface.

4. The block stability analysis method under the framework of continuous medium numerical analysis according to claim 1 is characterized in that: The rod elements in S3 are distributed at the mesh centroids on both sides of each block structural surface, and the length of the rod is based on just passing through the meshes on both sides of the structural surface. Based on the characteristic that the rod element just passes through the mesh centroids on both sides of the structural surface, the equivalent control area of ​​each rod element is the area of ​​the surface mesh it passes through. The tensile strength parameter and shear strength parameter of the rod element are the structural surface strength parameter multiplied by the equivalent control area of ​​the rod element.

5. The block stability analysis method under the framework of continuous medium numerical analysis according to claim 4 is characterized in that: Normal mechanical properties of the rod element in S3: ； Where, is the normal stiffness of the member unit, and its value is 10~1000 times the deformation modulus of the surrounding rock; is the equivalent control area of ​​the bar element; is the unit normal deformation of the member, positive indicates expansion deformation, negative indicates compression deformation; represents the normal force of the bar element, Indicates the maximum normal force that can be achieved by the member element; Tangential mechanical properties of rod elements: ； Where, is the tangential stiffness of the member unit, and its value is 10~1000 times the deformation modulus of the surrounding rock; is the unit tangential deformation of the member, represents the tangential force of the member element, and Indicates the maximum tangential force that the member element can achieve in two tangential directions; The tensile strength and shear strength of the bar element are: ； ； in, is the tensile strength of the block structure surface, is the cohesion of the block structure surface, is the friction angle of the block structural surface; for block analysis problems, these parameters can be obtained from geological survey data.

6. The block stability analysis method under the continuum numerical analysis framework according to claim 1 is characterized in that: During the calculation process in S5, the strength parameter of the rod element is assigned a maximum value to ensure that the rod element is in an elastic working state during the initial stress application process.

7. The block stability analysis method under the continuum numerical analysis framework according to claim 1 is characterized in that: The two situations in S6 specifically include: The first one is that the calculation finally converges, indicating that the block is currently in a stable state; the second one is that the calculation finally does not converge, indicating that the block is currently unstable.

8. The block stability analysis method under the framework of continuous medium numerical analysis according to claim 1 is characterized in that: The strength reduction in S7 is expressed by the following formula: ； ； ； Where, is the strength reduction factor, for the initial stable block, Gradually increase from 1.0 until the calculation does not converge, for the initial unstable block, Gradually decrease from 1.0 until the calculation begins to converge; is the tensile strength of the block structure surface, is the cohesion of the block structure surface, is the friction angle of the block structure surface; 、 、 Then they correspond respectively 、 、 Parameters after strength reduction; The safety factor of the block is the critical state of block instability obtained by strength reduction. The critical state of block instability is determined by the relationship curve between the displacement of the block characteristic point and the strength reduction coefficient. The critical point is characterized by a sudden increase in the slope of the curve, a sharp increase in deformation, and non-convergence of the calculation.

9. The block stability analysis method under the framework of continuous medium numerical analysis according to claim 1 is characterized in that: In said S8, the support force is applied to the free surface of the block in the form of a uniformly distributed load, and then the safety factor of the block after the support force is applied is further analyzed using the method shown in step S7 until the support force makes the safety factor of the block meet the requirements of the specification.

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