Block stability analysis method under continuum numerical analysis framework

Abstract

The invention provides a block stability analysis method under a continuum numerical analysis framework. The method comprises the following steps: S1, establishing a numerical analysis model; s2, carrying out continuous grid separation; s3, separating grids and reconstraining; s4, initial constraint application; s5, initial stress is applied; s6, obtaining an initial stable state of the block; s7, block safety coefficient analysis; and S8, determining the safety coefficient of the block body after supporting. The analysis method provided by the invention overcomes the limitation that the traditional block stability analysis needs to depend on a theoretical method and a discontinuous analysis method, and enriches the technical means of block stability analysis.

Description

Technical Field

[0001] The 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 an obviously heterogeneous material, and one of the most obvious manifestations of its heterogeneity is the various structural surfaces inside it. After the excavation of underground caverns and slopes, the structural surfaces in the rock mass and the excavation free surfaces may be combined to form independent blocks. These independent blocks have the risk of instability after the excavation surfaces of underground caverns and slopes are formed, which poses a great challenge to the stability of the surrounding rock of the project. Large blocks even pose a threat to personnel safety. Therefore, in the design and construction process of large underground caverns and slopes, block stability analysis is an indispensable content and one of the key issues concerning the stability of the surrounding rock of underground caverns and slopes. After block stability analysis, sufficient support can be provided for block support design to ensure the safety of underground caverns and slope projects.

[0003] At present, block stability analysis methods are mainly based on theoretical methods such as block theory, or non-continuous medium mechanics methods such as discrete element method. Although traditional continuous medium numerical analysis methods such as finite element method and finite difference method are the most widely used in factories, they are rarely used for block stability analysis due to the constraints of their own 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 limitation 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 realize the above technical features, the object of the present invention is achieved as follows: a block stability analysis method under a continuous medium numerical analysis framework comprises the following steps: S1, numerical analysis model establishment: A three-dimensional numerical analysis model of the block is established. In the framework of continuous medium numerical analysis, the 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 the bar element with tension, compression and shear dual constraints at the boundary of the block structure surface to re-constrain the boundary of the structure surface; S4, initial constraint imposition: There is no constraint 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 the 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 bar element are converted into actual strength parameters, and calculation and analysis are carried out. There are two cases for calculating the final results; S7, block safety factor analysis: On the basis of 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 units are adjusted; S8, determination of block safety factor after support: If the block safety factor obtained in step S7 does not meet the safety factor requirement specified in the specification, support measures need to be provided to stabilize the block.

[0006] Preferably, the numerical analysis model in S1 has 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.

[0007] 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.

[0008] Preferably, the rod units in S3 are distributed at the centroids of the grids 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 centroids of the grids 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.

[0009] Preferably, the normal mechanical properties of the bar element in S3 are: ; In the formula, 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 opening deformation, negative indicates compression deformation; represents the normal force of the bar element, It represents the maximum normal force that can be achieved by the bar element; Tangential mechanical properties of bar elements: ; In the formula, 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 bar element, and It represents the maximum tangential force that the bar 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.

[0010] 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.

[0011] Preferably, 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.

[0012] Preferably, the strength reduction in S7 is expressed by the following formula: ; ; ; In the formula, 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; The block safety factor 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.

[0013] Preferably, in 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.

[0014] Beneficial effects of the present invention: 1. The present invention proposes a method for carrying out block stability analysis under the framework of continuous medium numerical analysis, which overcomes the limitation 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

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 A schematic diagram of a method flow chart of an embodiment of the present invention.

[0017] Figure 2 Block structure surface information according to an embodiment of the present invention.

[0018] Figure 3 The overall numerical analysis model of the embodiment of the present invention.

[0019] Figure 4 The block shape of the numerical analysis model of the embodiment of the present invention.

[0020] Figure 5 A schematic diagram of grid separation according to an embodiment of the present invention.

[0021] Figure 6 Schematic diagram of separate grid re-constraint according to an embodiment of the present invention.

[0022] Figure 7 A locally enlarged schematic diagram of the separation grid re-constraint according to an embodiment of the present invention.

[0023] Figure 8 Schematic diagram of initial constraint application according to an embodiment of the present invention.

[0024] Fig. 9 Initial stress state of an embodiment of the present invention (unit: Pa).

[0025] Fig.10 The strength reduction process curve after support of the embodiment of the present invention.

[0026] Fig.11 (a) (b) are the normal mechanical and tangential mechanical properties of the bar element. DETAILED DESCRIPTION

[0027] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0028] Embodiment 1: The present invention provides a block stability analysis method under a continuous medium numerical analysis framework, comprising the following steps: 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; generally, at least two structural surfaces are required 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.

[0029] S2, continuous grid separation: Each node distributed on the block boundary is decomposed into two nodes. After the continuous mesh nodes are decomposed at the block boundary, the model at this time shows discontinuous characteristics at the block boundary, that is, there is no interaction on both sides of the block structure surface.

[0030] S3, separate the grid and then constrain it: At the boundary of the block structure surface, a rod unit with dual constraints of tension, compression and shear is introduced to re-constrain the boundary of the structure surface; the rod unit can be distributed at the centroid of the mesh on both sides of each block structure surface, and the length of the rod is based on just passing through the mesh on both sides of the structure surface. Since the rod unit just passes through the centroid of the mesh on both sides of the structure surface, the equivalent control area of ​​each rod unit is the mesh area of ​​the surface 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. The mechanical properties of the rod unit are as follows Fig.11 As shown in (a) and (b).

[0031] Normal mechanical properties of bar element: ; In the formula, 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 opening deformation, negative indicates compression deformation; represents the normal force of the bar element, It represents the maximum normal force that can be achieved by the bar element; Tangential mechanical properties of bar elements: ; In the formula, 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 bar element, and It represents the maximum tangential force that the bar 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 structure surface; for block analysis problems, these parameters can be obtained from geological survey data; S4, initial constraint imposition: There is no constraint 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; 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.

[0032] S6, obtain the initial stable state of the block: Based on step S5, the strength parameters of the rod element are converted into actual strength parameters, and calculation and analysis are 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.

[0033] S7, block safety factor analysis: On the basis of 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 units are adjusted; Strength reduction is expressed by the following formula: ; ; ; In the formula, 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; The block safety factor 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.

[0034] S8, determination of block safety factor after support: If the block safety factor 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. The support force is applied to the free surface of the block in the form of surface force, and then the block safety factor after the support force is applied is further analyzed using the method shown in step S7 until the support force makes the block safety factor meet the specification requirements.

[0035] Embodiment 2: 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: Step S1: Establish a three-dimensional continuous numerical model including the boundary morphology of the block structure surface to be analyzed.

[0036] For ease of explanation, the embodiments of the present invention are described below by taking an example of an underground powerhouse block of a hydropower station.

[0037] The structural surface cataloging information of the downstream side wall of a power station main building during the construction period shows that there is a block. The block is composed of three structural surfaces and the main building excavation free surface. The three structural surfaces are: fissure J1, EW / S∠55°~75°; fissure J5-1, N60~90°E / SE∠10~30°; fault fCF-2, N45°~55°E / SE∠85°, such as Figure 2 shown.

[0038] Firstly, 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, such as Figure 4 As shown; and the outer side 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.

[0039] Step S2: For the continuous grid model of block stability analysis, separation processing is performed at the boundary of the structural surface.

[0040] 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 time, the block of the embodiment of the present invention is completely disconnected from the surrounding rock.

[0041] Step S3: For the separated block stability analysis separated grid model, the bar element is used to re-constrain the structural surface boundary.

[0042] 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 and the triangular surface mesh on the surrounding rock side of the structural surface are the same. Figure 6 and Figure 7 According to step S3, a rod unit is inserted at the block structure surface. The rod unit is based on just passing through the triangular surface mesh. The rod unit can be inserted at the centroid of each triangular surface mesh.

[0043] 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 26.56°, the cohesion c of cracks J1 and J5-1 is 0.15MPa, and the friction angle is 35°. Use the mechanical properties of the bar element in step S3 to set the normal stiffness of the bar element and tangential stiffness are 100 times the deformation modulus of the rock mass, i.e. 2250 GPa; the cohesion c of the rod element on J1 and J5-1 is set to 0.15 MPa, and the friction angle is 35°, the cohesion c of the upper bar 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 unit 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.

[0044] Step S4: Initial constraint application. No constraints are imposed on the free surface of the block, and boundary normal constraints are imposed on other boundaries.

[0045] For 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 cave and block size by more than 3 times, it has exceeded the influence range of the block. Normal fixed constraints can be applied to the side boundaries and bottom boundaries of the model, such as Figure 8 shown.

[0046] Step S5: Applying the initial stress state. 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 the cavern excavation. 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.

[0047] In step S4, normal constraints are applied to the side boundaries 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 assigned 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 Set to 89.9°, tensile strength Set to 100GPa; on this basis, the self-weight stress field can be generated by solving.

[0048] According to engineering geological data, the horizontal geostress lateral pressure coefficient in the vertical side wall direction of this embodiment is about 1.1, and the geostress lateral pressure coefficient in the direction of the cave axis is about 1.54. Based on the self-weight stress field obtained by solving, the stress component in the vertical side wall direction of the model area and the stress component in the direction of the cave axis are respectively set equal to the self-weight stress multiplied by the corresponding geostress lateral pressure coefficient; after the calculation is converged, the complete original rock stress field of the cave area can be obtained.

[0049] 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 original rock stress field, simulated excavation of the cavern area is carried out. After the calculation is converged, the stress field information of the surrounding rock after the cavern excavation is obtained, such as Fig. 9 shown.

[0050] Step S6: Obtain the initial stable state of the block. Based on the above, the strength parameters of the rod unit 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 converge, indicating that the block is currently unstable.

[0051] For this embodiment, based on step S5, the block boundary bar element is adjusted again to the bar element parameters established in step S3. Then, the solution is directly obtained. If the solution fails to converge, it indicates that the initial state of the block cannot stabilize itself, that is, the block is an initially unstable block.

[0052] 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 bar unit are adjusted. The strength reduction can be expressed by the following formula.

[0053] 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.

[0054] Step S8: Determine the block safety factor after support. For the block safety factor obtained in S7, if it does not meet the safety factor requirements specified in the specification, support measures need to be provided to stabilize the block. The support force can be applied to the free surface of the block in the form of surface force, and then the block safety factor after the support force is applied is further analyzed using the method shown in S7 until the support force makes the block safety factor meet the specification requirements.

[0055] 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 cave, 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, Fig.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; When it is 3.8, the calculation does not converge. 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.

[0056] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a 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 introduced and described 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, the 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 the bar element with tension, compression and shear dual constraints at the boundary of the block structure surface to re-constrain the boundary of the structure surface; S4, initial constraint imposition: There is no constraint 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 bar element are converted into actual strength parameters, and calculation and analysis are carried out. There are two cases for calculating the final results; S7, block safety factor analysis: On the basis of 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 units are adjusted; S8, determination of block safety factor after support: If the block safety factor obtained in step S7 does not meet the safety factor requirement specified in the specification, support measures need to be provided to stabilize the block.

2. According to the block stability analysis method in the framework of continuous medium numerical analysis as described in claim 1, it is characterized in that: The numerical analysis model in S1 must have at least two structural surfaces to form 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. According to the block stability analysis method in the framework of continuous medium numerical analysis as claimed in claim 1, it 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 units in S3 are distributed at the mesh centroids of both sides of each block structural surface, and the length of the rod is based on just passing through the meshes of both sides of the structural surface; based on the characteristic that the rod unit just passes through the mesh centroids of both sides of the structural surface, the equivalent control area of ​​each rod unit is the mesh area of ​​the surface 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.

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 bar element in S3: ； In the formula, 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 opening deformation, negative indicates compression deformation; represents the normal force of the bar element, It represents the maximum normal force that can be achieved by the bar element; Tangential mechanical properties of bar elements: ； In the formula, 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 bar element, and It represents the maximum tangential force that the bar 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 framework of continuous medium numerical analysis 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 framework of continuous medium numerical analysis 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: ； ； ； In the formula, 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; The block safety factor 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 the step 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 analyzed by 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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