An underground engineering support design method, system, device and storage medium based on a rock damage and fracture degree index

Abstract

The present invention provides a method, system, device and medium for supporting design of underground engineering based on the index of rock damage and fracture degree. The method comprises the following steps: S1, determination of the pre-peak and post-peak stress-strain curve of the rock; S2, evaluation of the brittle-ductile degree of the rock; S3, construction of the index of rock damage and fracture degree; S4, determination of the supporting design method. Through the four steps of obtaining the pre-peak and post-peak stress-strain curve of the rock, evaluating the brittle-ductile degree of the rock, constructing the index of rock damage and fracture degree, and establishing the supporting design method, and through the embedding and calculation of the index of rock damage and fracture degree in the numerical simulation software, a cloud map of the damage and fracture degree of the surrounding rock after the excavation of the underground engineering is obtained. According to the safety level of the engineering construction, the supporting design parameters are determined to achieve the comprehensive purpose of controllable damage and fracture, safety and stability, and optimal support for the underground engineering.

Description

Technical Field

[0001] The present invention belongs to the field of underground engineering, and particularly relates to a method, system, device and storage medium for designing underground engineering support based on the index of rock damage and fracture degree. Background Art

[0002] With the continuous development of the national economy, the rigid demands for energy, resources, water conservancy and hydropower, transportation and environment in China are increasing day by day, which promotes the continuous progress of engineering construction such as mine roadways, water conservancy tunnels, hydropower caverns, highway and railway tunnels from the surface to the underground space. The study of surrounding rock stability control is the primary issue in the safe construction of underground engineering. The instability of the surrounding rock is a reflection that the bearing potential of the surrounding rock mass and the support strength are insufficient to match the process of stress adjustment of the surrounding rock. Therefore, it is imperative to propose a method for designing underground engineering support based on the index of rock damage and fracture degree, which is of great significance for the safe and stable control of underground engineering.

[0003] Scholars and engineers at home and abroad have formed a series of relatively common design methods for underground engineering through long-term engineering practices, such as the Prandtl pressure arch theory, the mining method, the New Austrian Tunneling Method, the load-structure method, the convergence-confinement method, the new Italian method, the engineering analogy method, etc. However, with the increasing influence of underground engineering depth and tectonic movement, the characteristics of high in-situ stress are becoming more prominent. The instability of the surrounding rock of underground engineering is more caused by the rupture of the internal rock mass of the surrounding rock due to high stress concentration. The previous design methods for underground engineering emphasized timely support for the surrounding rock after excavation, highlighting the requirement that the excavation causes less disturbance to the surrounding rock mass, and the support measures should minimize the degree and depth of surrounding rock fracture to ensure the integrity and bearing capacity of the surrounding rock, so as to exert the self-supporting potential of the surrounding rock.

[0004] Engineering practice shows that the cracking of shallow surrounding rock after the excavation of underground engineering is inevitable. Reasonably utilizing the stress concentration of the surrounding rock to limit the expansion of surrounding rock fracture within a controllable range and fully mobilizing the self-bearing capacity of the deep rock mass of the surrounding rock is the most favorable way to maximize the self-supporting potential of the surrounding rock. Therefore, it is very necessary to form a method for designing underground engineering support based on the index of rock damage and fracture degree. Summary of the Invention

[0005] The first object of the present invention is to provide a method for designing underground engineering support based on the index of rock damage and fracture degree in view of the above-mentioned problems.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for supporting design of underground engineering based on the index of rock damage and fracture degree, through the embedding and calculation of the index of rock damage and fracture degree in numerical simulation software, obtaining the cloud map of the damage and fracture degree of the surrounding rock after the excavation of underground engineering, and determining the support design parameters according to the safety level of engineering construction. Specifically, it includes the following steps:

[0008] S1. Obtain the stress-strain curve of the rock before and after the peak;

[0009] S2. Evaluation of the brittle-ductile degree of the rock: According to the stress-strain curves of the rock under different surrounding rocks obtained in step S1, establish an evaluation index for the brittle-ductile degree of the rock RBD ;

[0010] S3. Construction of the index of rock damage and fracture degree: According to the stress-strain curves of the rock under different surrounding rocks obtained in step S1 and the evaluation index for the brittle-ductile degree of the rock established in step S2 RBD , establish the index of rock damage and fracture degree RDF ;

[0011] S4. Determination of the support design method: According to the index of rock damage and fracture degree constructed in step S3 RDF , determine the classification results of the rock damage and fracture degree, and determine the corresponding support measures according to different classification results.

[0012] While adopting the above technical solution, the present invention can also adopt or combine the following technical solutions:

[0013] As a preferred technical solution of the present invention: In step S1, perform non-destructive sampling at the engineering site, the core diameter is not less than 120 mm, and then finely process it into a standard cylindrical specimen with a diameter of 50 mm and a height of 100 mm, and use a high-rigidity triaxial experimental instrument to carry out a conventional triaxial compression test.

[0014] 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.

[0015] As a preferred technical solution of the present invention: In step S2, establish an evaluation index for the brittle-ductile degree of the rock RBD , and the formula is as follows:

[0016]

[0017]

[0018] In the formula, , are the peak strength and residual strength of the rock respectively, corresponding to the peak point and the lowest point after the peak of the stress-strain curve; is the brittleness index of the rock; is the rate of the stress-strain curve of the rock after the peak drops from the peak strength to the residual strength; is the brittleness index of the rock and the confining pressure The slope of the linear fitting line.

[0019] As a preferred technical solution of the present invention: in step S3, an index for the degree of rock damage and fracture is established RDF , and the formula is as follows:

[0020]

[0021]

[0022] In the formula, is the initiation strength of the rock, corresponding to the inflection point where the concave section of the stress-strain curve of the rock before the peak starts to turn into a straight line section; is the confining pressure at which the stress-strain curve of the rock after the peak changes from brittle drop to ductile platform, RBD is the evaluation index for the brittle-ductile degree of the rock, , , are the plastic strain, peak plastic strain, and residual plastic strain of the rock respectively, are the loading stresses at different times of the rock stress-strain curve respectively, The confining pressure of the rock loading test.

[0023] As a preferred technical solution of the present invention: in step S4, the index for the degree of rock damage and fracture is embedded in the numerical simulation software for calculation to obtain the cloud map of the degree of surrounding rock damage and fracture after the excavation of the underground project. The determination of the support design method requires the optimization of the support parameters. The optimization of the support parameters requires the dynamic adjustment of the support time, support length, and support strength. Calculate the cloud map results of the degree of surrounding rock damage and fracture under different combinations of support parameters until the requirements of the engineering surrounding rock damage and fracture control level are met. The optimization formula for the support design parameters is as follows:

[0024]

[0025] In the formula, are the support time, support length, and support strength of the bolt / cable respectively, is the depth of the surrounding rock damage and fracture, is the allowable value of the degree of rock damage and fracture for the project, RDF is the index for the degree of rock damage and fracture, is the depth of the acceptable range of rock damage and fracture for the project, is the control value of the depth of the engineering surrounding rock damage and fracture.

[0026] The second object of the present invention is to provide an underground engineering support design system based on the index of rock damage and fracture degree, which includes the following modules:

[0027] A module for obtaining the pre-peak and post-peak stress-strain curve of rock, which is used to obtain the pre-peak and post-peak stress-strain curve of rock;

[0028] A module for evaluating the brittle-ductile degree of rock, which is used to evaluate the brittle-ductile degree of rock in real time;

[0029] A module for constructing the index of rock damage and fracture degree, which is used to construct the index of rock damage and fracture degree;

[0030] A module for determining the support design method, which is used to determine the support design method.

[0031] The third object of the present invention is to provide an electronic device, which includes a processor, a communication interface, a memory, and a communication bus. The processor, the communication interface, and the memory complete mutual communication through the communication bus. The characteristics are as follows:

[0032] A memory, which is used to store computer programs;

[0033] A processor, which is used to execute the computer program stored on the memory to implement the steps of the underground engineering support design method based on the index of rock damage and fracture degree as described above.

[0034] 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 the index of rock damage and fracture degree as described above are implemented.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] Through four steps of obtaining the pre-peak and post-peak stress-strain curve of rock, evaluating the brittle-ductile degree of rock, constructing the index of rock damage and fracture degree, and establishing the support design method, and through the embedding and calculation of the index of rock damage and fracture degree in the numerical simulation software, a cloud map of the damage and fracture degree of the surrounding rock after the excavation of the underground project is obtained. According to the safety level of the project construction, the support design parameters are determined to achieve the comprehensive purpose of controllable damage and fracture, safety and stability, and optimal support of the underground project. Description of the Drawings

[0037] Figure 1a It is a stress-strain curve graph of typical rocks under different confining pressures.

[0038] Figure 1b It is a fitting result diagram of peak strength and residual strength of typical rocks under different confining pressures.

[0039] Figure 2a It is a schematic diagram of the calculation and value-taking of the brittleness index of rocks with different brittle-ductile degrees.

[0040] Figure 2b It is a fitting result diagram of the brittleness index of rocks under different confining pressures.

[0041] Figure 3a It is a schematic diagram of the calculation of the damage and fracture degree index of rocks under brittle conditions.

[0042] Figure 3b It is a schematic diagram of the calculation of the damage and fracture degree index of rocks under ductile conditions.

[0043] Figure 4 It is a numerical calculation contour map of the damage and fracture degree of the surrounding rock of underground engineering. Specific implementation manner

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] A design method for the support of underground engineering based on the damage and fracture degree index of rocks. By embedding and calculating the damage and fracture degree index of rocks in numerical simulation software, a contour map of the damage and fracture degree of the surrounding rock after the excavation of underground engineering is obtained. According to the safety level of engineering construction, the safety level of engineering construction is a system for classifying the safety requirements of engineering based on factors such as the importance, scale, use function, and potential risks of the project, ensuring the safety of the project in the design stage. According to the "Unified Standard for the Reliability Design of Building Structures", the engineering construction level can be divided into first-class, second-class, and third-class, and the support design parameters are determined. Specifically, the following steps are included:

[0046] S1. Obtain the pre-peak to post-peak stress-strain curve of the rock;

[0047] Take non-destructive samples at the engineering site. The core diameter is not less than 120 mm, and then it is finely processed into a standard cylindrical specimen with a diameter of 50 mm and a height of 100 mm. Using a high-rigidity triaxial test instrument, carry out a conventional triaxial compression test. The confining pressure levels of the test are 0, 5, 10, 20, 30, 50 MPa (the test confining pressure is not less than 50 MPa), and not less than 5 groups of tests are repeated under each confining pressure level to measure the pre-peak to post-peak stress-strain curve of the rock. Typical results are as Figure 1aAs shown, the maximum value of the test confining pressure reached 80 MPa, and complete pre-peak to post-peak stress-strain curves under different surrounding rocks were obtained through testing. In particular, the stress-strain curve of the post-peak residual section (corresponding to the horizontal section curve after the peak) provides basic data for calculating the evaluation index of the brittle-ductile degree of rocks and the evaluation index of the damage and fracture degree of rocks (the initiation strength, peak strength, residual strength, peak plastic strain, and residual plastic strain under different confining pressures).

[0048] S2. Evaluation of the brittle-ductile degree of rocks: According to the stress-strain curves of rocks under different surrounding rocks obtained in step S1, an evaluation index for the brittle-ductile degree of rocks is established RBD ;

[0049] According to the stress-strain curve results of rocks under different surrounding rocks measured in step S1, an evaluation index for the brittle-ductile degree of rocks is established RBD , and the formula is as follows:

[0050]

[0051]

[0052] In the formula, and are the peak strength and residual strength of the rock respectively, corresponding to the peak point and the lowest point after the peak of the stress-strain curve, as Figure 2a shown; is the brittleness index of the rock, is the falling rate of the stress-strain curve of the rock from the peak strength to the residual strength after the peak (corresponding to the slope of the line connecting points ac or AC in Figure 2a ), is the brittleness index of the rock and the slope of the linear fitting line of the confining pressure , as Figure 2b shown.

[0053] S3. Construction of the evaluation index for the damage and fracture degree of rocks: According to the stress-strain curves of rocks under different surrounding rocks obtained in step S1 and the evaluation index for the brittle-ductile degree of rocks established in step S2 RBD , an evaluation index for the damage and fracture degree of rocks is established RDF ;

[0054] Based on the results of steps S1 and S2, an evaluation index for the damage and fracture degree of rocks is established RDF , and the formula is as follows:

[0055]

[0056]

[0057] In the formula, and are the peak strength and residual strength of the rock, respectively, is the cracking strength of the rock, corresponding to the inflection point where the concave section of the stress-strain curve before the peak of the rock begins to turn into a straight line segment, are the loading stresses at different times of the rock stress-strain curve, is the confining pressure of the rock loading test, such as Figure 1a shown; is the confining pressure at which the stress-strain curve after the peak of the rock changes from brittle drop to ductile platform, such as Figure 1a shown as 80 MPa, which can be determined by measuring the intersection point of the curve or the fitting line of the peak strength - residual strength; RBD is the evaluation index of the brittle-ductile degree of the rock; 、 、 are the plastic strain, peak plastic strain, and residual plastic strain of the rock, respectively. The peak plastic strain and residual plastic strain are solved at the corresponding peak strength and residual strength moments. A straight line with a slope equal to the elastic modulus of the rock can be drawn using the strength at that time, and the intersection point of the straight line and the horizontal axis can be obtained, such as Figure 3b shown.

[0058] S4. Determination of the support design method: According to the rock damage and fracture degree index RDF constructed in step S3, determine the classification results of the rock damage and fracture degree, and determine the corresponding support measures according to different classification results.

[0059] According to step S3, determine the classification of the rock damage and fracture degree, as shown in Table 1.

[0060] Table 1 Classification table of rock damage and fracture degree

[0061]

[0062] Embed the rock damage and fracture degree index into the numerical simulation software for calculation, and construct a geomechanical model of the underground project. Input the mechanical parameters of the engineering rock mass to obtain the cloud map of the damage and fracture degree of the surrounding rock after the excavation of the underground project, such as Figure 4 shown.

[0063] RDF = 1.0 can be regarded as the key value for controlling rock damage and fracture, RDF The area with an isoline or cloud map of ≥ 1.0 is the area of medium and above damage and fracture of the surrounding rock, and support measures must be taken on the engineering site to deal with it.

[0064] The determination of the support design method requires the optimization of support parameters. The optimization of support parameters requires the dynamic adjustment of the support time, support length, and support strength, and calculating the cloud map results of the surrounding rock damage and fracture degree under different combinations of support parameters until the requirements of the surrounding rock damage and fracture control level of the project are met and the support cost is optimal. The optimization formula for the support design parameters is as follows:

[0065]

[0066] In the formula, respectively represent the support time, support length, and support strength of the bolt / cable, is the depth of the surrounding rock damage and fracture, is the measured value of the allowable rock damage and fracture degree in the project, generally taking 0.8, and RDF is the rock damage and fracture degree index, is the depth of the acceptable rock damage and fracture range in the project, is the control value of the surrounding rock damage and fracture depth in the project. The recommended values are shown in Table 2, where: D is the equivalent diameter of the project chamber. The support length of the bolt / cable should at least exceed the position of the isoline with RDF = 0.8.

[0067] Table 2 Classification Table of the Control of the Surrounding Rock Damage and Fracture Depth in the Project

[0068]

[0069] The present invention also provides an underground engineering support design system based on the rock damage and fracture degree index, including the following modules:

[0070] A module for obtaining the pre-peak and post-peak stress-strain curve of the rock, which is used to obtain the pre-peak and post-peak stress-strain curve of the rock;

[0071] A module for evaluating the brittle-ductile degree of the rock, which is used to evaluate the brittle-ductile degree of the rock in real time;

[0072] A module for constructing the rock damage and fracture degree index, which is used to construct the rock damage and fracture degree index;

[0073] A module for determining the support design method, which is used to determine the support design method.

[0074] The present invention also provides an electronic device, which includes a processor, a communication interface, a memory, and a communication bus. The processor, communication interface, and memory complete mutual communication through the communication bus.

[0075] The memory is used to store a computer program;

[0076] A processor, which is configured to execute a computer program stored in a memory to implement the steps of the underground engineering support design method based on the rock damage and fracture degree index as described above.

[0077] The present invention also provides a non-transitory readable storage medium, a non-volatile storage medium storing an executable program, which, when executed by a processor, implements the steps of the underground engineering support design method based on the rock damage and fracture degree index as described above.

[0078] So far, the technical solution of the present invention has been described in conjunction with the specific experimental process shown in the drawings. However, the protection scope of the present invention is not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can 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 support design method for underground engineering based on the index of rock damage and fracture degree, characterized in that: By embedding and calculating the rock damage and fracture degree index in the numerical simulation software, the cloud map of the surrounding rock damage and fracture degree after the excavation of the underground project is obtained. According to the safety level of the project construction, the support design parameters are determined. Specifically, it includes the following steps: S1. Obtain the pre-peak and post-peak stress-strain curves of the rock; S2. Evaluation of rock brittle-ductile degree: Based on the stress-strain curves of the rock under different surrounding rocks obtained in step S1, establish an evaluation index for the rock brittle-ductile degree RBD ; S3. Construction of rock damage and fracture degree index: Based on the stress-strain curves of rocks under different surrounding rocks obtained in step S1 and the evaluation index of rock brittle-ductile degree established in step S2 RBD , establish the 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 rock damage and fracture degree, and determine the corresponding support measures according to different classification results; In step S3, a rock damage and fracture degree index RDF is established, and the formula is as follows: In the formula, and are the peak strength and residual strength of the rock respectively, is the initiation strength of the rock, corresponding to the inflection point where the concave section of the stress-strain curve before the peak of the rock begins to turn into a straight line section; is the confining pressure at which the stress-strain curve after the peak of the rock changes from brittle drop to ductile plateau, and RBD is the evaluation index of the brittle-ductile degree of the rock, and and are the plastic strain, peak plastic strain, and residual plastic strain of the rock respectively, are the loading stresses at different times of the rock stress-strain curve respectively, is the confining pressure of the rock loading test.

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

3. The method according to claim 2, wherein: The confining pressure levels of the triaxial compression test are 0, 5, 10, 20, 30, and 50 MPa respectively.

4. The method according to claim 1, characterized in that: In step S2, an evaluation index for the brittle-ductile degree of the rock is established RBD , and the formula is as follows: In the formula, and 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 the brittleness index of the rock, is the dropping rate of the stress-strain curve of the rock from the peak strength to the residual strength after the peak, is the brittleness index of the rock and the slope of the linear fitting line of the confining pressure ​ 5. 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 the cloud map of the surrounding rock damage and fracture degree after the excavation of the underground project is obtained. To determine the support design method, the support parameters need to be optimized. The optimization of the support parameters requires dynamic adjustment of the support time, support length, and support strength. Calculate the results of the cloud map of the surrounding rock damage and fracture degree under different combinations of support parameters until the requirements of the surrounding rock damage and fracture control level of the project are met. The optimization formula of the support design parameters is as follows: Wherein, are respectively the support time, support length, and support strength of the bolt / cable bolt, is the depth of surrounding rock damage and fracture, is the magnitude value of the allowable rock damage and fracture degree for the project, RDF is the index of rock damage and fracture degree, is the depth of the acceptable rock damage and fracture range for the project, is the control value of the surrounding rock damage and fracture depth for the project.

6. An underground engineering support design system based on a rock damage and fracture degree index, characterized in that, It includes the following modules: A pre-peak and post-peak stress-strain curve acquisition module for the rock, which is used to obtain the pre-peak and post-peak stress-strain curves of the rock; A rock brittle-ductile degree evaluation module, and the rock brittle-ductile degree evaluation and monitoring module is used to evaluate the rock brittle-ductile degree in real time; A rock damage and fracture degree index construction module, which is used to construct a rock damage and fracture degree index; The rock damage and fracture degree index construction module operates according to the following steps: Establish a rock damage and fracture degree index RDF, and the formula is as follows: In the formula, and are the peak strength and residual strength of the rock respectively, is the cracking strength of the rock, corresponding to the inflection point where the concave section of the stress-strain curve before the peak of the rock begins to turn into a straight line section; is the confining pressure at which the stress-strain curve after the peak of the rock changes from brittle drop to ductile plateau, and RBD is the evaluation index of the brittle-ductile degree of the rock, and and are the plastic strain, peak plastic strain, and residual plastic strain of the rock respectively, are the loading stresses at different times of the rock stress-strain curve, is the confining pressure of the rock loading test; A support design method determination module, which is used to determine the support design method.

7. An electronic device, the electronic device includes a processor, a communication interface, a memory, and a communication bus. The processor, communication interface, and memory complete mutual communication through the communication bus. It is characterized in that: A memory, which is used to store a computer program; A processor, which is used to execute the computer program stored on the memory to implement the steps of the underground project support design method based on the rock damage and fracture degree index as described in any one of claims 1-5.

8. 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, it implements the steps of the underground project support design method based on the rock damage and fracture degree index as described in any one of claims 1-5.

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