Underground engineering support design method, system and equipment based on rock damage and fracture degree index and storage medium

Abstract

The invention provides an underground engineering support design method, system and equipment based on a rock damage and fracture degree index and a medium. The method comprises the following steps: S1, measuring a rock pre-peak-post-peak stress-strain curve; s2, evaluating the brittleness and ductility degree of the rock; s3, rock damage and fracture degree index construction; and S4, determining a support design method. The method comprises the following four steps: obtaining a rock pre-peak-post-peak stress-strain curve, evaluating the brittle-ductile degree of rock, constructing a rock damage and fracture degree index and determining a support design method, and obtaining a surrounding rock damage and fracture degree cloud picture after underground engineering excavation through embedding and calculating the rock damage and fracture degree index in numerical simulation software. And according to the engineering construction safety level, support design parameters are determined, and the comprehensive purposes of underground engineering damage and fracture controllability, safety, stability and optimal support are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of underground engineering, and specifically relates to an underground engineering support design method, system, equipment and storage medium based on rock damage and fracture degree indicators. Background Art

[0002] With the continuous development of the national economy, my country's rigid demand for energy, resources, water conservancy and hydropower, transportation and environment is increasing, prompting the construction of mining shafts, water conservancy tunnels, hydropower caverns, highway and railway tunnels to continuously move from the surface to the underground space. The study of surrounding rock stability control is the primary issue for the safe construction of underground projects, and the instability of surrounding rock is a reflection of the surrounding rock body bearing potential and support strength being insufficient to match the surrounding rock stress adjustment process. Therefore, it is imperative to propose a support design method for underground projects based on rock damage and fracture degree indicators, which is of great significance to the safety and stability control of underground projects.

[0003] After long-term engineering practice, scholars and engineers at home and abroad have formed a series of relatively common underground engineering design methods, such as the Proctor pressure arch theory, mining method, New Austrian method, load-structure method, convergence-constraint method, new method, engineering analogy method, etc. However, with the increasing depth of underground engineering and the influence of tectonic movement, the characteristics of high ground stress are becoming more and more prominent. The instability of the surrounding rock of underground engineering is more due to the high stress concentration causing the internal rock mass of the surrounding rock to rupture. In the past, the design method of underground engineering emphasized the timely support of the surrounding rock after excavation, emphasizing the requirement that the excavation should cause less disturbance to the surrounding rock mass, and the support measures should minimize the degree and depth of surrounding rock rupture to ensure the integrity and bearing capacity of the surrounding rock, so as to give full play to the self-supporting potential of the surrounding rock.

[0004] Engineering practice shows that cracking of shallow surrounding rock is inevitable after underground excavation. The most favorable way to maximize the self-supporting potential of surrounding rock is to rationally utilize surrounding rock stress concentration to limit the expansion of surrounding rock rupture within a controllable range and fully mobilize the self-bearing capacity of deep rock mass in the surrounding rock. Therefore, it is very necessary to form an underground engineering support design method based on rock damage and rupture degree indicators. Summary of the invention

[0005] The first object of the present invention is to provide an underground engineering support design method based on rock damage and fracture degree indicators in response to the above-mentioned problems.

[0006] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions: A method for designing underground engineering support based on rock damage and fracture degree index, by embedding and calculating the rock damage and fracture degree index in numerical simulation software, obtains a cloud map of surrounding rock damage and fracture degree after underground engineering excavation, and determines support design parameters according to the engineering construction safety level, specifically, including the following steps: S1. Obtaining the pre-peak and post-peak stress-strain curve of rock; S2. Evaluation of rock brittleness and ductility: Based on the stress-strain curves of different surrounding rocks obtained in step S1, establish rock brittleness and ductility evaluation index RBD ; S3. Construction of rock damage and fracture degree index: Based on the stress-strain curves of different surrounding rocks obtained in step S1 and the rock brittleness evaluation index established in step S2 RBD , establish rock damage and fracture degree index RDF ; S4. Determination of support design method: Based on the rock damage and fracture degree index constructed in step S3 RDF , determine the classification results of the degree of rock damage and fracture, and determine the corresponding support measures based on different classification results.

[0007] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions: As a preferred technical solution of the present invention: in step S1, non-destructive sampling is carried out at the engineering site, the core diameter is not less than 120 mm, and then it is finely processed into a cylindrical standard specimen with a diameter of 50 mm and a height of 100 mm, and a conventional triaxial compression test is carried out using a high-rigidity triaxial experimental instrument.

[0008] As a preferred technical solution of the present invention: the confining pressure levels of the triaxial compression test are 0, 5, 10, 20, 30, and 50 MPa, respectively.

[0009] As a preferred technical solution of the present invention: in step S2, establish a rock brittleness evaluation index RBD , the formula is as follows:

[0010]

[0011] In the formula, , are the peak strength and residual strength of the rock, corresponding to the peak point and the lowest point after the peak of the stress-strain curve, respectively; It is an indicator of rock brittleness; is the rate at which the post-peak stress-strain curve of rock drops from peak strength to residual strength; The brittleness index of the rock Confining pressure The slope of the linear fit line.

[0012] As a preferred technical solution of the present invention: in step S3, a rock damage and fracture degree index is established. RDF , the formula is as follows:

[0013]

[0014] In the formula, is the crack initiation strength of the rock, corresponding to the inflection point where the concave section of the pre-peak stress-strain curve of the rock begins to transform into a straight line section; is the confining pressure at which the post-peak stress-strain curve of rock changes from brittle drop to ductile platform, RBD It is an evaluation index of rock brittleness and ductility. , , are the rock plastic strain, peak plastic strain and residual plastic strain respectively. The loading stress at different moments of the rock stress-strain curve, Confining pressure for rock loading tests.

[0015] As a preferred technical solution of the present invention: in step S4, the rock damage and fracture degree index is embedded in the numerical simulation software for calculation, and a cloud map of the damage and fracture degree of the surrounding rock after the underground engineering excavation is obtained. The support design method needs to be determined to optimize the support parameters. The support parameter optimization needs to dynamically adjust the support time, support length, and support strength. The cloud map results of the surrounding rock damage and fracture degree under different support parameter combinations are calculated until the requirements for the control level of the surrounding rock damage and fracture of the engineering are met. The support design parameter optimization formula is as follows:

[0016] In the formula, They are the anchor / cable support time, support length, and support strength. is the depth of surrounding rock damage and rupture, is the value of rock damage and fracture degree allowed in the project, RDF is an indicator of rock damage and fracture degree. is the depth of the rock damage and fracture range acceptable for engineering, It is the control value of the damage and fracture depth of the surrounding rock of the project.

[0017] The second object of the present invention is to provide an underground engineering support design system based on rock damage and fracture degree indicators, comprising the following modules: A rock pre-peak-post-peak stress-strain curve acquisition module, wherein the rock pre-peak-post-peak stress-strain curve acquisition module is used to acquire a rock pre-peak-post-peak stress-strain curve; A rock brittleness and ductility evaluation module, wherein the rock brittleness and ductility evaluation and monitoring module is used to evaluate the rock brittleness and ductility in real time; A rock damage and fracture degree index construction module, wherein the rock damage and fracture degree index construction module is used to construct a rock damage and fracture degree index; A support design method determination module, wherein the support design method determination module is used to determine the support design method.

[0018] The third object of the present invention is to provide an electronic device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus, and wherein: A memory, the memory being used to store a computer program; A processor is used to execute the computer program stored in the memory to implement the steps of the underground engineering support design method based on the rock damage and fracture degree index as described above.

[0019] Another object of the present invention is to provide a non-volatile storage medium, in which an executable program is stored. When the executable program is executed by a processor, the steps of the underground engineering support design method based on rock damage and fracture degree indicators as described above are implemented.

[0020] Compared with the prior art, the present invention has the following beneficial effects: Through four steps of obtaining rock pre-peak and post-peak stress-strain curve, rock brittleness and ductility evaluation, rock damage and fracture degree index construction, and support design method establishment, the rock damage and fracture degree cloud map of surrounding rock after underground engineering excavation is obtained by embedding and calculating the rock damage and fracture degree index in numerical simulation software. According to the safety level of engineering construction, the support design parameters are determined to achieve the comprehensive goals of controllable damage and fracture of underground engineering, safe and stable, and optimal support. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1a Figure 2 is the stress-strain curve of typical rock under different confining pressures.

[0022] Figure 1b This is the fitting result diagram of peak strength and residual strength of typical rocks under different confining pressures.

[0023] Figure 2a Schematic diagram of calculating the brittleness index under different brittleness and ductility levels of rocks.

[0024] Figure 2b This is the fitting result diagram of brittleness index of rock under different confining pressures.

[0025] Figure 3a Schematic diagram for calculating damage and fracture degree index under rock brittle conditions.

[0026] Figure 3b Schematic diagram of calculation of damage and fracture degree index under rock ductility conditions.

[0027] Figure 4 This is a numerical calculation cloud diagram of the damage and fracture degree of surrounding rock in underground engineering. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] A method for designing underground engineering support based on rock damage and fracture degree index, by embedding and calculating the rock damage and fracture degree index in numerical simulation software, a cloud map of surrounding rock damage and fracture degree after underground engineering excavation is obtained. According to the engineering construction safety level, the engineering construction safety level is a system for classifying engineering safety requirements according to factors such as the importance, scale, use function and potential risks of the project, so as to ensure the safety of the project in the design stage. According to the "Uniform Standard for Reliability Design of Building Structures", the engineering construction level can be divided into level one, level two and level three, and the support design parameters are determined. Specifically, the following steps are included: S1. Obtaining the pre-peak and post-peak stress-strain curve of rock; Non-destructive sampling is carried out at the project site. The core diameter is not less than 120 mm. Then it is finely processed into a cylindrical standard specimen with a diameter of 50 mm and a height of 100 mm. Conventional triaxial compression tests are carried out using a high-rigidity triaxial experimental instrument. The test confining pressure levels are 0, 5, 10, 20, 30, and 50 MPa (the test confining pressure is not less than 50 MPa). At least 5 groups of tests are repeated at each surrounding rock level to determine the pre-peak-post-peak stress-strain curve of the rock. Typical results are as follows Figure 1a As shown in the figure, the maximum test confining pressure reached 80 MPa. The test obtained complete pre-peak and post-peak stress-strain curves under different surrounding rocks, especially the post-peak residual stress-strain curve (corresponding to the post-peak horizontal section curve), which provided basic data for the calculation of rock brittleness and ductility evaluation indicators and rock damage and fracture degree indicators (cracking initiation strength, peak strength, residual strength, peak plastic strain and residual plastic strain under different confining pressures).

[0030] S2. Evaluation of rock brittleness and ductility: Based on the stress-strain curves of different surrounding rocks obtained in step S1, establish rock brittleness and ductility evaluation index RBD ; According to the stress-strain curve results of different surrounding rocks measured in step S1, the rock brittleness and ductility evaluation index is established RBD , the formula is as follows:

[0031]

[0032] In the formula, , are the peak strength and residual strength of the rock, corresponding to the peak point and the lowest point after the peak of the stress-strain curve, respectively. Figure 2a As shown; is an indicator of rock brittleness. is the rate at which the rock post-peak stress-strain curve drops from peak strength to residual strength (corresponding to Figure 2a The slope of the line connecting two points AC or AC in The brittleness index of the rock Confining pressure The slope of the linear fit line is Figure 2b shown.

[0033] S3. Construction of rock damage and fracture degree index: Based on the stress-strain curves of different surrounding rocks obtained in step S1 and the rock brittleness evaluation index established in step S2 RBD , establish rock damage and fracture degree index RDF ; Based on the results of steps S1 and S2, establish the rock damage and fracture degree index RDF , the formula is as follows:

[0034]

[0035] In the formula, , are the peak strength and residual strength of the rock, is the crack initiation strength of the rock, corresponding to the inflection point where the concave section of the pre-peak stress-strain curve of the rock begins to transform into a straight line section. The loading stress at different moments of the rock stress-strain curve, The confining pressure of rock loading test is as follows: Figure 1a As shown; is the confining pressure at which the post-peak stress-strain curve of rock changes from brittle drop to ductile platform, such as Figure 1a The 80 MPa shown can be determined by measuring the intersection of the curve or the peak strength-residual strength fitting line; RBD It is an evaluation index of rock brittleness and ductility; , , They are rock plastic strain, peak plastic strain, and residual plastic strain. The peak plastic strain and residual plastic strain are respectively expressed by the corresponding peak strength and residual strength The solution can be obtained by using the strength at that time to draw a straight line with a slope equal to the elastic modulus of the rock. The intersection of the straight line and the horizontal axis can be obtained, such as Figure 3b shown.

[0036] S4. Determination of support design method: Based on the rock damage and fracture degree index constructed in step S3 RDF , determine the classification results of the degree of rock damage and fracture, and determine the corresponding support measures based on different classification results.

[0037] According to step S3, the classification of rock damage and fracture degree is determined, as shown in Table 1.

[0038] Table 1 Rock damage and fracture degree classification table

[0039] The rock damage and fracture degree index is embedded in the numerical simulation software for calculation, and the underground engineering geomechanics model is constructed. The engineering rock mass mechanics parameters are input to obtain the surrounding rock damage and fracture degree cloud map after underground engineering excavation, such as Figure 4 shown.

[0040] RDF =1.0 can be regarded as the key value for controlling rock damage and fracture. RDF The area with contour line or cloud map ≥1.0 is the area with medium or above damage and rupture of surrounding rock, and support measures must be taken at the project site to deal with it.

[0041] The determination of the support design method requires the optimization of the support parameters. The optimization of support parameters requires the dynamic adjustment of the support time, support length, and support strength. The cloud map results of the surrounding rock damage and fracture degree under different support parameter combinations are calculated until the requirements of the surrounding rock damage and fracture control level of the project are met and the support cost is optimal. The support design parameter optimization formula is as follows:

[0042] In the formula, They are the anchor / cable support time, support length, and support strength. is the depth of surrounding rock damage and rupture, is the rock damage and fracture degree value allowed in the project, generally taken as 0.8, and RDF is the rock damage and fracture degree index. is the depth of the rock damage and fracture range acceptable for engineering, is the control value of the damage and fracture depth of the surrounding rock of the project. The recommended values ​​are shown in Table 2, where: D The equivalent diameter of the engineering cavern. Anchor rod / cable support length At least it must exceed the contour position of RDF=0.8.

[0043] Table 2 Classification table for control of damage and fracture depth of surrounding rock in projects

[0044] The present invention also provides an underground engineering support design system based on rock damage and fracture degree index, comprising the following modules: A rock pre-peak-post-peak stress-strain curve acquisition module, wherein the rock pre-peak-post-peak stress-strain curve acquisition module is used to acquire a rock pre-peak-post-peak stress-strain curve; A rock brittleness and ductility evaluation module, wherein the rock brittleness and ductility evaluation and monitoring module is used to evaluate the rock brittleness and ductility in real time; A rock damage and fracture degree index construction module, wherein the rock damage and fracture degree index construction module is used to construct a rock damage and fracture degree index; A support design method determination module, wherein the support design method determination module is used to determine the support design method.

[0045] The present invention also provides an electronic device, the electronic device comprises a processor, a communication interface, a memory and a communication bus, the processor, the communication interface and the memory communicate with each other via the communication bus, Memory, memory is used to store computer programs; The processor is used to execute the computer program stored in the memory to implement the steps of the underground engineering support design method based on the rock damage and fracture degree index as described above.

[0046] The present invention also provides a non-transitory readable storage medium and a non-volatile storage medium, in which an executable program is stored. When the executable program is executed by a processor, the steps of the underground engineering support design method based on rock damage and fracture degree indicators as described above are implemented.

[0047] So far, the technical solutions of the present invention have been described in conjunction with the specific experimental processes shown in the accompanying drawings, but the protection scope of the present invention is not limited to these specific implementations. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for designing underground engineering support based on rock damage and fracture degree index, characterized by: By embedding and calculating the rock damage and fracture degree index in the numerical simulation software, the surrounding rock damage and fracture degree cloud map after underground engineering excavation is obtained. According to the safety level of engineering construction, the support design parameters are determined. Specifically, the following steps are included: S1. Obtaining the pre-peak and post-peak stress-strain curve of rock; S2. Evaluation of rock brittleness and ductility: Based on the stress-strain curves of different surrounding rocks obtained in step S1, establish rock brittleness and ductility evaluation index RBD ; S3. Construction of rock damage and fracture degree index: Based on the stress-strain curves of different surrounding rocks obtained in step S1 and the rock brittleness evaluation index established in step S2 RBD , establish rock damage and fracture degree index RDF ; S4. Determination of support design method: Based on the rock damage and fracture degree index constructed in step S3 RDF , determine the classification results of the degree of rock damage and fracture, and determine the corresponding support measures based on different classification results.

2. The method according to claim 1, characterized in that: In step S1, non-destructive sampling is carried out at the engineering site, the core diameter is not less than 120 mm, and then it is finely processed into a cylindrical standard specimen with a diameter of 50 mm and a height of 100 mm. A conventional triaxial compression test is carried out using a high-rigidity triaxial experimental instrument.

3. The method according to claim 2, characterized in that: The confining pressure levels of the triaxial compression tests were 0, 5, 10, 20, 30, and 50 MPa, respectively.

4. The method according to claim 1, characterized in that: In step S2, establish the rock brittleness evaluation index RBD , the formula is as follows: In the formula, , are the peak strength and residual strength of the rock, corresponding to the peak point and the lowest point after the peak of the stress-strain curve, respectively; is an indicator of rock brittleness. is the rate at which the rock post-peak stress-strain curve drops from peak strength to residual strength, The brittleness index of the rock Confining pressure The slope of the linear fit line.

5. The method according to claim 1, characterized in that: In step S3, establish the rock damage and fracture degree index RDF , the formula is as follows: In the formula, , are the peak strength and residual strength of the rock, is the crack initiation strength of the rock, corresponding to the inflection point where the concave section of the pre-peak stress-strain curve of the rock begins to transform into a straight line section; is the confining pressure at which the post-peak stress-strain curve of rock changes from brittle drop to ductile platform, RBD It is an evaluation index of rock brittleness and ductility. , , are the rock plastic strain, peak plastic strain and residual plastic strain respectively. The loading stress at different moments of the rock stress-strain curve, Confining pressure for rock loading tests.

6. The method according to claim 1, characterized in that: In step S4, the rock damage and fracture degree index is embedded in the numerical simulation software for calculation, and a cloud map of the surrounding rock damage and fracture degree after underground engineering excavation is obtained. The support design method needs to be determined to optimize the support parameters. The support parameter optimization needs to dynamically adjust the support time, support length, and support strength. The surrounding rock damage and fracture degree cloud map results under different support parameter combinations are calculated until the surrounding rock damage and fracture control level requirements of the engineering are met. The support design parameter optimization formula is as follows: In the formula, They are the anchor / cable support time, support length, and support strength. is the depth of surrounding rock damage and rupture, is the value of rock damage and fracture degree allowed in the project, RDF is an indicator of rock damage and fracture degree. is the depth of the rock damage and fracture range acceptable for engineering, It is the control value of the damage and fracture depth of the surrounding rock of the project.

7. An underground engineering support design system based on rock damage and fracture degree index, characterized in that: Includes the following modules: A rock pre-peak-post-peak stress-strain curve acquisition module, wherein the rock pre-peak-post-peak stress-strain curve acquisition module is used to acquire a rock pre-peak-post-peak stress-strain curve; A rock brittleness and ductility evaluation module, wherein the rock brittleness and ductility evaluation and monitoring module is used to evaluate the rock brittleness and ductility in real time; A rock damage and fracture degree index construction module, wherein the rock damage and fracture degree index construction module is used to construct a rock damage and fracture degree index; A support design method determination module, wherein the support design method determination module is used to determine the support design method.

8. An electronic device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus, characterized in that: A memory, the memory being used to store a computer program; A processor, wherein the processor is used to execute a computer program stored in a memory to implement the steps of the underground engineering support design method based on rock damage and fracture degree indicators as described in any one of claims 1 to 6.

9. A non-volatile storage medium, characterized in that: The non-volatile storage medium stores an executable program, and when the executable program is executed by the processor, the steps of the underground engineering support design method based on rock damage and fracture degree indicators as claimed in any one of claims 1 to 6 are implemented.

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