Surrounding rock stability simulation method and system of abandoned roadway grouting transformation compressed air energy storage reservoir

Abstract

The invention relates to the technical field of compressed air energy storage, in particular to a surrounding rock stability simulation method and system for a compressed air energy storage reservoir transformed by waste roadway grouting, and the method comprises the following steps: determining initial geomechanical conditions, and determining geological strength index values of a damaged area, a damaged area and a disturbed area around a compressed air energy storage chamber; simulating software is called, a waste roadway surrounding rock three-dimensional entity model containing the random fractures is constructed by utilizing the material attributes of the different partitions, grouting diffusion range simulation is conducted on the obtained entity model, and an obtained simulation result is imported into three-dimensional modeling software; obtaining a gas storage model containing grid lines and importing the gas storage model into a three-dimensional numerical analysis program; calling a grouting reinforcement fractured rock creep damage model under circulating pressure-storage-gas discharge disturbance, and embedding the model into a three-dimensional numerical analysis program; based on a three-dimensional numerical analysis program, under the influence of different factors, numerical simulation analysis is carried out on the evolution law of a surrounding rock stress field and a deformation field during the service period of the compressed air storage reformed by the abandoned roadway after grouting reinforcement.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage, and specifically to a method and system for simulating the surrounding rock stability of a compressed air energy storage reservoir with grouting reinforcement in abandoned roadways. Background Technique

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] Compressed air energy storage is a peak shaving technology to cope with power grid fluctuations. By using compressed air as a carrier, excess electric energy is used to store compressed air in a gas storage reservoir during low electricity consumption periods, and air is released during peak periods to mix with fuel to drive a gas turbine to generate electricity. The entire process includes the processes of compressing air, storing gas, and releasing gas, and can cycle for charging and discharging energy to balance power supply and demand.

[0004] The gas storage reservoir is an important part of the compressed air energy storage technology. Generally, a gas storage reservoir needs to occupy a large amount of ground space. The remaining underground spaces and facilities generated by some retiring or abandoned mines have great potential for resource recycling. The underground spaces such as abandoned mine roadways can be used to construct gas storage reservoirs, which can reduce costs in terms of raw materials, land use, etc. However, these abandoned roadways have experienced long-term use, and the supporting structures are damaged. The stability and bearing capacity of the surrounding rock may be difficult to meet the requirements of gas storage.

[0005] To solve this problem, grouting reinforcement is generally used to improve the strength of the supporting structure of abandoned mines. When numerically simulating the grouting reinforcement of a gas storage reservoir transformed from an abandoned roadway, more damage parameters and damage evolution models need to be introduced in the prior art, which will significantly increase the complexity of the model. Therefore, the initial damage of the surrounding rock is usually not considered. In the process of numerical simulation, if the initial damage of the surrounding rock is not considered, it will affect the diffusion range of its grouting reinforcement, resulting in large errors in the numerical simulation results such as the stress field and displacement field when numerically simulating the gas storage reservoir after the transformation of the abandoned roadway under the cyclic charging-storing-discharging gas state. Summary of the Invention

[0006] In order to solve the technical problems existing in the above background technique, the present invention provides a method and system for simulating the surrounding rock stability of a compressed air energy storage reservoir with grouting reinforcement in abandoned roadways, which conforms to the actual situation, generates random fractures around the chamber to simulate the properties of the surrounding rock in the real state, numerically simulates its grouting reinforcement, combines the diffusion range of its grouting reinforcement to numerically simulate the cyclic compression-storage-discharge gas state, and finally analyzes its stress and deformation fields in the cyclic charging-storing-discharging gas state to meet the requirements of compressed air energy storage.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a simulation method for surrounding rock stability of a compressed air energy storage reservoir with grouting reconstruction in abandoned roadways, including the following steps:

[0009] Determine the initial geomechanical conditions and determine the geological strength index values of the failure zone, damage zone, and disturbed zone around the compressed air energy storage chamber;

[0010] Call the simulation software, use the material properties of different partitions to construct a three-dimensional solid model of the surrounding rock of the abandoned roadway with random fractures, simulate the grouting diffusion range of the obtained solid model, import the obtained simulation results into the three-dimensional modeling software, obtain a gas storage reservoir model with grid lines and import it into the three-dimensional numerical analysis program;

[0011] Call the creep damage model of grouting-reinforced fractured rock under cyclic compression-storage-discharge gas disturbance, and embed it into the three-dimensional numerical analysis program; Based on the three-dimensional numerical analysis program, numerically simulate and analyze the evolution laws of the surrounding rock stress field and deformation field during the service period of the compressed air gas storage reservoir reconstructed from the abandoned roadway after grouting reinforcement under the influence of different factors.

[0012] As a further implementation method, to determine the geological strength index values of the failure zone, damage zone, and disturbed zone around the compressed air energy storage chamber, specifically: By sampling the rock mass in each partition and obtaining the joint spacing of the specimens, as well as the angle between the joint groups, calculate the block volume and the joint condition factor, and determine the geological strength index values of the corresponding partitions of each specimen through the look-up table method.

[0013] As a further implementation method, call the simulation software and use the material properties of different partitions to construct a three-dimensional solid model of the surrounding rock of the abandoned roadway with random fractures, specifically: Call the "Discrete Fracture Network - 3D" plug-in in the simulation software, define the fracture sizes, directions, and attribute parameters of different regions in the failure zone, damage zone, and disturbed zone, and generate a three-dimensional solid model of the surrounding rock of the abandoned roadway with random fractures.

[0014] As a further implementation method, simulate the grouting diffusion range of the obtained solid model, specifically: Call the Darcy's law interface in the porous media and groundwater flow sub-modules under the fluid flow module in the simulation software, define different parameters for the failure zone, damage zone, disturbed zone, and external surrounding rock, and numerically simulate the grouting diffusion range of the three-dimensional solid model of the surrounding rock of the abandoned roadway with random fractures.

[0015] As a further implementation method, during the numerical simulation of the grouting diffusion range, divide the model into grids according to the requirements of the Darcy's law interface, and use the finite element method to transform the continuous physical field problem into a discrete algebraic equation system, and obtain the numerical simulation results through discretized solution of the Darcy equation.

[0016] As a further implementation method, a creep damage model of grouting-reinforced fractured rock under cyclic pressure-storage-unloading gas disturbance is established. According to the test results and the principle of stress dissipation, a nonlinear viscous pot mechanical element is used to replace the Newtonian viscous pot in the Burgers creep model, and a nonlinear viscoplastic damage element is used to control the presence or absence of the unstable creep stage and describe the deformation characteristics of the unstable creep stage. Thus, a creep damage model of grouting-reinforced fractured rock under cyclic pressure-storage-unloading gas disturbance is established.

[0017] As a further implementation method, in a three-dimensional numerical analysis program, the Hoek-Brown constitutive model is selected to describe the mechanical behavior of grouting-reinforced fractured rock. By writing the corresponding Fish function, the calculation logic of the creep damage model of grouting-reinforced fractured rock under cyclic pressure-storage-unloading gas disturbance is determined. The written Fish function is embedded into the gas storage reservoir model with grid lines, and the model is verified and calibrated by comparing with test data or actual engineering cases.

[0018] The second aspect of the present invention provides a surrounding rock stability simulation system for a compressed air energy storage reservoir reconstructed by grouting in abandoned roadways, including:

[0019] An initial condition module, configured to: determine the initial geomechanical conditions and determine the geological strength index values in the damaged area, damaged area, and disturbed area around the compressed air energy storage chamber;

[0020] A grouting diffusion simulation module, configured to: call simulation software, construct a three-dimensional solid model of the surrounding rock of the abandoned roadway with random fractures by using the material properties of different partitions, simulate the grouting diffusion range of the obtained solid model, import the obtained simulation results into three-dimensional modeling software, obtain a gas storage reservoir model with grid lines and import it into a three-dimensional numerical analysis program;

[0021] A numerical simulation module, configured to: call the creep damage model of grouting-reinforced fractured rock under cyclic pressure-storage-unloading gas disturbance and embed it into a three-dimensional numerical analysis program; based on the three-dimensional numerical analysis program, numerically simulate and analyze the evolution laws of the surrounding rock stress field and deformation field during the service period of the compressed air energy storage reservoir reconstructed from the abandoned roadway after grouting reinforcement under the influence of different factors.

[0022] The third aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps in the above-mentioned surrounding rock stability simulation method for a compressed air energy storage reservoir reconstructed by grouting in abandoned roadways are implemented.

[0023] The fourth aspect of the present invention provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps in the above-mentioned surrounding rock stability simulation method for a compressed air energy storage reservoir reconstructed by grouting in abandoned roadways are implemented.

[0024] Compared with the prior art, the above one or more technical solutions have the following beneficial effects:

[0025] During the simulation, the initial damage of the surrounding rock was considered. By dividing the surrounding rock of the abandoned roadway into zones, different fissures were generated according to the property requirements of the surrounding rock in different zones of the abandoned roadway, and grouting simulation was carried out on the roadway containing fissures to obtain the contour map of its effective reinforcement range. By considering the initial damage, the grouting parameters such as grouting pressure and grouting volume can be optimized according to the actual state of the surrounding rock. This optimization not only improves the grouting effect but also reduces the material waste and construction risks caused by unreasonable parameters; this refined simulation makes the grouting reinforcement design more targeted, can effectively improve the grouting effect, and reduce the risk of reinforcement failure caused by unclear fissure distribution. In the transformation of abandoned roadways by traditional grouting reinforcement technology, due to the lack of accurate assessment of the initial state of the surrounding rock, a large number of grouting tests and repeated construction are often required. This solution determines the effective reinforcement range through simulation, avoids unnecessary grouting areas, and thus reduces the material and labor costs. After grouting reinforcement of the abandoned roadway for compressed air energy storage, numerical simulation of the thermal-mechanical coupling of the surrounding rock deterioration of the compressed air energy storage reservoir in the abandoned roadway under the influence of different factors is carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0027] Figure 1 is a flowchart of the method for simulating the surrounding rock stability of the compressed air energy storage reservoir in the abandoned roadway after grouting transformation provided by one or more embodiments of the present invention;

[0028] Figure 2 is a GSI chart provided by one or more embodiments of the present invention;

[0029] Figure 3 is a diagram of the diffusion range of surrounding rock grouting reinforcement simulated by COMSOL provided by one or more embodiments of the present invention;

[0030] Figure 4 is a sectional view of the diffusion of surrounding rock grouting reinforcement simulated by COMSOL provided by one or more embodiments of the present invention;

[0031] Figure 5 is a model diagram of the compressed air energy storage gas storage reservoir constructed by using Rhino 3D NURBS provided by one or more embodiments of the present invention;

[0032] Figure 6It is the result diagram of the 1st vertical stress and the 100th vertical stress when the compressed air energy storage gas storage reservoir simulated by FLAC3D stores gas under the condition of the same buried depth provided by one or more embodiments of the present invention;

[0033] Figure 7 It is the result diagram of the 1st vertical displacement and the 100th vertical displacement when the compressed air energy storage gas storage reservoir simulated by FLAC3D stores gas under the condition of the same buried depth provided by one or more embodiments of the present invention;

[0034] Figure 8 It is the result diagram of the 1st horizontal stress and the 100th horizontal stress when the compressed air energy storage gas storage reservoir simulated by FLAC3D stores gas under the condition of the same buried depth provided by one or more embodiments of the present invention;

[0035] Figure 9 It is the result diagram of the 1st horizontal displacement and the 100th horizontal displacement when the compressed air energy storage gas storage reservoir simulated by FLAC3D stores gas under the condition of the same buried depth provided by one or more embodiments of the present invention;

[0036] Figure 10 It is the result diagram of the vertical stress when the compressed air energy storage gas storage reservoir simulated by FLAC3D stores gas at the buried depths of 100m and 200m respectively under the gas storage state provided by one or more embodiments of the present invention;

[0037] Figure 11 It is the result diagram of the vertical displacement when the compressed air energy storage gas storage reservoir simulated by FLAC3D stores gas at the buried depths of 100m and 200m respectively under the gas storage state provided by one or more embodiments of the present invention;

[0038] Figure 12 It is the result diagram of the horizontal stress when the compressed air energy storage gas storage reservoir simulated by FLAC3D stores gas at the buried depths of 100m and 200m respectively under the gas storage state provided by one or more embodiments of the present invention;

[0039] Figure 13 It is the result diagram of the horizontal displacement when the compressed air energy storage gas storage reservoir simulated by FLAC3D stores gas at the buried depths of 100m and 200m respectively under the gas storage state provided by one or more embodiments of the present invention. Detailed implementation manners

[0040] The present invention will be further described below in conjunction with the drawings and embodiments.

[0041] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0042] Term explanation:

[0043] A disused roadway refers to a roadway that was once used for passage, mining, or other purposes but is now abandoned and no longer in use. These roadways may be located underground in cities, deep in mines, or other places, abandoned for various reasons, and may become dangerous due to long-term lack of maintenance.

[0044] The following embodiments provide a simulation method and system for the surrounding rock stability of a compressed air energy storage reservoir reconstructed by grouting in a disused roadway. Random fractures are generated around the chamber to simulate the properties of the surrounding rock in the real state, and then numerical simulation of grouting reinforcement is carried out. Combining the diffusion range of its grouting reinforcement, numerical simulation under the cyclic compression-storage-degasification state is carried out. Finally, the stress and deformation fields under the cyclic charging-storage-degasification state are analyzed to meet the requirements of compressed air energy storage.

[0045] Embodiment 1:

[0046] As Figure 1 shown, the simulation method for the surrounding rock stability of a compressed air energy storage reservoir reconstructed by grouting in a disused roadway includes the following steps:

[0047] Step 1: Determine the initial geomechanical conditions, that is, determine the GSI values (Geological Strength Index, a parameter used to measure the strength and stability of geological rocks) of the damaged area, damaged area, and disturbed area around the compressed air energy storage chamber.

[0048] In this embodiment, by taking typical rock masses in each partition for on-site measurement to obtain their various data, the block volume (V b ) and joint condition factor (J c ) are calculated through the following formulas (1) and (2), where s i and r i are the joint spacing and the angle between joint sets respectively, and their data are obtained through on-site measurement. J c , J w , and J A are the large-scale fluctuation, small-scale smoothness, and combined change factors respectively, and their specific data are obtained through on-site measurement. Figure 2 For the GSI table, substitute the calculated block volume (V b ) and joint condition factor (J c ) into the GSI chart, find the value corresponding to the calculated block volume (V b ), and then find the value corresponding to the joint condition factor (J c ). The intersection of these two values is the GSI value of the rock mass.

[0049]

[0050] Step 2: Use the three-dimensional discrete fracture network plug-in in simulation software (such as COMSOL) to generate a three-dimensional solid model of the surrounding rock of the abandoned roadway containing random fractures for the damaged area, damaged area, and disturbed area in the gas storage reservoir;

[0051] To simulate the actual situation of the surrounding rock of the chamber, the surrounding rock of the chamber is divided into zones, different material properties are defined according to different zones, and random fractures that conform to the actual working conditions are generated. The positions of the fractures follow a uniform random distribution function, the sizes follow a power-law distribution function, and the directions follow a Fisher distribution; by adjusting the parameters of the power-law distribution function, the distribution of fracture sizes is changed, thereby affecting the fracture density.

[0052] In the main screen toolbar of COMSOL, select the display selection in the selection command to create a display selection of geometric entities for the damaged area, damaged area, and disturbed area around the chamber respectively, so as to select the zones in the discrete fracture plug-in to generate fractures with different parameters respectively. Add the "Discrete Fracture Network - 3D" plug-in in the underground water flow in the plug-in library of the development tool option bar, return to the model developer, open the "Discrete Fracture Network - 3D" settings window under the global definition, and define the fracture sizes (minimum axis length, maximum axis length, power-law), directions (strike, dip angle, dispersion coefficient), and property (porosity, roughness coefficient, pore size distribution, size factor) parameters of different zones according to the previously set display selections of the damaged area, damaged area, and disturbed area.

[0053] This plug-in can generate a fracture network according to the actual geological conditions, and set the parameters such as the position, size, and direction of the fractures according to a certain random distribution law. For example, the fracture positions follow a uniform random distribution function, the sizes follow a power-law distribution function, and the directions follow a Fisher distribution. This randomness can better simulate the disordered distribution characteristics of fractures in nature, making the generated fracture network closer to the actual geological conditions. Secondly, this plug-in is suitable for creating discrete fracture networks in real geometries and can handle complex geometries such as reservoirs and rock formations. This means that when simulating working conditions with complex geometric shapes, the plug-in can accurately generate fractures in these geometric shapes, ensuring the accuracy of the simulation results.

[0054] Step 3: Use the Darcy's law interface in the porous media and underground water flow sub-modules under the fluid flow module in simulation software (such as COMSOL) to numerically simulate the grouting diffusion range of the model with three-dimensional fractures already generated.

[0055] Darcy's law describes the flow of fluid through the pores in a fully saturated porous medium. This movement is mainly driven by the pressure gradient, and the momentum transfer caused by the shear stress of the fluid can be ignored. Its mathematical expression is where u is the Darcy velocity, k is the permeability, and μ is the dynamic viscosity of the fluid. is the pressure gradient. The software determines the diffusion path and range of the fluid in the porous medium by analyzing the simulated pressure and velocity distributions.

[0056] In the software, different parameters are defined for the failure zone, damage zone, disturbed zone, and the external surrounding rock respectively. The permeability of the failure zone is 1×10 -12 m 2 , and the porosity is 0.464; the permeability of the damage zone is 1×10 -14 m 2 , and the porosity is 0.1; the permeability of the disturbed zone is 1×10 -16 m 2 , and the porosity is 0.02. The external surrounding rock is defined using granite from the built-in material library. The density of the grout material is 1700 kg / m3, and the dynamic viscosity is 1×10 -3 Pa·s.

[0057] To consider the influence of gravity on the pressure gradient during the grout diffusion process, in the Darcy's law settings window, select the checkbox including gravity to consider the gravity effect of the grout during grouting. Since the gravitational potential energy of the fluid is related to the height, in order to make the calculation of the gravitational potential energy more intuitive, the bottom of the gas storage reservoir model is defined as the gravity reference position. Gravity will change the flow direction and velocity of the grout, which is crucial for accurately simulating the diffusion range of the grout under complex geological conditions. Considering that the liquid in Darcy's law is mainly driven by the pressure gradient, the inlet is defined as the grouting channel and the outlet is defined as all external boundaries in the software. To simplify the boundary condition setting of the model, the outlet pressure is defined as 0 MPa and the inlet pressure is defined as 4 MPa.

[0058] The mesh generation uses the physical field control network. In this embodiment, the COMSOL software will automatically generate the mesh according to the selected Darcy's law interface. The mesh element size is selected as normal. The complete mesh contains 169892 domain elements, 24310 boundary elements, and 6221 edge elements. In COMSOL, according to the physical field control mesh generation, the software will automatically mesh the model according to the requirements of the Darcy's law interface. After mesh generation, the finite element method is used to discretize and solve the Darcy equation. The finite element method transforms the continuous physical field problem into a discrete algebraic equation system, enabling complex fluid flow problems to be solved on a computer. In order to obtain a range of the grout diffusion reaching stability, a steady state is considered for the research calculation. Figure 3 is the grouting reinforcement diffusion range diagram for the compressed air energy storage roadway, Figure 4 The figure shows its diffusion range diagram of the cross-section on the y-axis.

[0059] Step 4: In the Comsol simulation results in Step 3, make five cross-sections with the same spacing along the depth direction of the slurry diffusion range, then sketch the contour map of each cross-section, and import the contour line data into a 3D modeling software (such as Rhino 3D NURBS) for lofting to form a 3D solid model. Figure 5 It is the gas storage reservoir model built in Rhino.

[0060] Step 5: Use the Kubrix plug-in in the 3D modeling software Rhino to import the built and meshed gas storage reservoir model into a 3D numerical analysis program (such as FLAC3D).

[0061] Step 6: Embed the creep damage model of grouting-reinforced fractured rock under cyclic pressure-storage-gas unloading disturbance in FLAC3D. This model is based on the test results of the long-term bearing characteristics of grouting-reinforced fractured rock under cyclic pressure-storage-gas unloading disturbance, analyzes the stress and deformation mechanisms of grouting-reinforced fractured rock under cyclic pressure-storage-gas unloading disturbance. During the fatigue process, the deformation of grouting-reinforced fractured rock gradually accumulates. When the deformation increases to a certain extent, cracks will appear in the grouting-reinforced fractured rock. Therefore, based on the stress dissipation principle, a nonlinear viscous pot mechanical element (DS viscous pot) is introduced to replace the Newtonian viscous pot in the Burgers creep model, and at the same time, a new nonlinear viscoplastic damage element (a stress threshold switch element and a strain-triggered viscous element in parallel) is introduced to control the presence or absence of the unstable creep stage and describe the deformation characteristics of the unstable creep stage. Thus, a creep damage model of grouting-reinforced fractured rock under cyclic pressure-storage-gas unloading disturbance is established, and a damage variable is established according to the Kachanov creep damage theory, providing a basis for the numerical simulation test of this embodiment.

[0062] In FLAC3D, first, the Hoek-Brown constitutive model needs to be selected to describe the mechanical behavior of grouting-reinforced fractured rock. By writing the corresponding Fish function, the calculation logic of the creep damage model of grouting-reinforced fractured rock under cyclic pressure-storage-gas unloading disturbance is realized. Embed the written Fish function into the FLAC3D model, and verify and calibrate the model through comparison with test data or actual engineering cases. Adjust the model parameters to make the calculation results of the model as consistent with the actual situation as possible to ensure the accuracy and reliability of the model. This model can comprehensively consider the stress and displacement characteristics of rock under cyclic pressure-storage-gas unloading disturbance, more accurately describe the long-term deformation and strength attenuation law of rock, and provide a more reliable theoretical basis for rock mechanics analysis.

[0063] Step 7: Simulate the evolution laws of the stress field and deformation field of the surrounding rock under the influence of different factors in FLAC3D.

[0064] In this embodiment, aiming at the problem of the stress characteristics of the compressed air energy storage chamber, based on the thermo-mechanical coupling theory, a thermo-mechanical coupling numerical simulation analysis method is adopted to explore the structural stresses and the spatial distribution and change process of the deformation of the surrounding rock and lining of the compressed air energy storage chamber under the operating conditions of the power station. The stress field and deformation field of the gas storage cavern are simulated under different factors of 1 and 100 cycles of compression-storage-gas discharge and burial depths of 100 m and 200 m respectively.

[0065] Step Eight: Analyze the numerical simulation results.

[0066] Analyze the simulation result diagrams of FLAC3D. Figure 6 Figs. are the vertical stress diagrams after 1 cycle of compression-storage-gas discharge and 100 cycles of compression-storage-gas discharge when the gas filling is completed. Figure 7 Figs. are the results diagrams of 1-time vertical stress and 100-time vertical displacement when the compressed air energy storage gas storage cavern stores gas under the same burial depth condition. It can be seen from Figure 6 that the stress distribution shows obvious regularity. Around the gas storage cavern, the stress values are relatively high, and as the distance from the gas storage cavern wall increases, the stress values gradually decrease. This is due to the action of the gas pressure stored inside the gas storage cavern, resulting in a large stress on the gas storage cavern wall. By comparison, it can be seen that after multiple cycles, the stress values near the gas storage cavern wall are released, which may be due to the plastic deformation and stress redistribution of the rock mass during multiple cycles. It can be seen from Figure 7 that after 100 cycles of gas charging and discharging, the surrounding rock at the bottom of the chamber has a larger deformation and deformation range compared to that after one cycle of gas charging and discharging.

[0067] Figure 8 and Figure 9 Figs. are the results diagrams of 1-time horizontal stress, 100-time horizontal stress and horizontal displacement when the compressed air energy storage gas storage cavern stores gas under the same burial depth condition respectively. It can be seen from Figure 8 that under the gas storage state after one cycle of gas charging and discharging, the change of the internal pressure of the chamber has a relatively significant pressure effect on the chamber wall. In the area far from the chamber wall, the horizontal stress gradually transitions from pressure to tension, and the stress values gradually decrease, showing the characteristics of stress diffusion and attenuation from the chamber wall to the distance. After multiple cycles, the pressure values near the chamber wall increase, which may be due to the plastic deformation and stress redistribution of the rock mass during multiple cycles. It can also be seen from the horizontal displacement diagram of Figure 8 that the horizontal displacement decreases with the increase of the distance from the chamber periphery, but the horizontal displacement of the surrounding rock after 1 cycle of gas charging and discharging is generally smaller than that of the surrounding rock after 100 cycles.

[0068] Figure 10 and Figure 11The figures of vertical stress and vertical displacement at the buried depths of 100m and 200m respectively under the gas storage state of the compressed air energy storage gas storage cavern. From Figure 10 and Figure 11 it can be seen that for the cavern at a buried depth of 100m under the gas storage state, the vertical compressive stress borne by the surrounding rock around it is smaller than that of the upper surrounding rock of the cavern at a buried depth of 200m, and the difference in the vertical compressive stress borne by the lower surrounding rock is not significant. For the surrounding rock of the gas storage cavern at a buried depth of 100m, its upper part mainly moves upward, and the lower surrounding rock mainly moves downward. The reason may be that the gas in the gas storage cavern exerts a compressive stress on the surrounding rock of the cavern, causing it to displace towards the surrounding; for the surrounding rock of the gas storage cavern at a buried depth of 200m, its upper surrounding rock mainly moves downward, and the lower surrounding rock mainly moves upward. The farther away from the gas storage cavern, the smaller its influence.

[0069] Figure 12 and Figure 13 The figures of horizontal stress and horizontal displacement at the buried depths of 100m and 200m respectively under the gas storage state of the compressed air energy storage gas storage cavern. From this, it can be known that under the gas storage state, the upper surrounding rock of the gas storage cavern with a shallower buried depth bears a greater horizontal stress than that of the gas storage cavern with a greater buried depth, but their stress distribution laws are the same. Both the upper and lower surrounding rocks bear tensile stress, while both the left and right sides bear compressive stress. The horizontal displacement of the gas storage cavern at a buried depth of 200m is smaller than that at a buried depth of 100m, but their distribution laws are still the same, and the farther away from the gas storage cavern, the smaller the horizontal displacement.

[0070] By dividing the surrounding rock of the abandoned roadway into zones, generating different fissures according to the property requirements of the surrounding rock in different zones of the abandoned roadway, and carrying out grouting simulation on the roadway containing fissures to obtain the contour map of its effective reinforcement range, the cost is reduced and the efficiency is improved.

[0071] After grouting and strengthening the compressed air energy storage abandoned roadway, numerical simulation of the deterioration of the surrounding rock of the grouting - modified abandoned roadway compressed air energy storage cavern under the influence of different factors is carried out.

[0072] The evolution laws of the surrounding rock stress field and deformation field, the surrounding rock damage and deterioration laws and mechanisms are simulated under the disturbances of cyclic pressure - storage - unloading with 1 time and 100 times and buried depths of 100m and 200m for the gas storage cavern.

[0073] Example 2:

[0074] The surrounding rock stability simulation system for the grouting - modified compressed air energy storage cavern of the abandoned roadway, including:

[0075] The initial condition module, configured to: determine the initial geomechanical conditions, and determine the geological strength index values of the damaged zone, damaged area and disturbed area around the compressed air energy storage cavern;

[0076] The grouting diffusion simulation module is configured to: call simulation software, construct a three-dimensional solid model of the surrounding rock of the abandoned roadway with random fractures by using the material properties of different partitions, simulate the grouting diffusion range of the obtained solid model, import the obtained simulation results into three-dimensional modeling software, obtain a gas storage reservoir model with grid lines and import it into a three-dimensional numerical analysis program;

[0077] The numerical simulation module is configured to: call the creep damage model of grouting-reinforced fractured rock under cyclic pressure-storage-unloading gas disturbance, embed it into a three-dimensional numerical analysis program; based on the three-dimensional numerical analysis program, numerically simulate and analyze the evolution laws of the stress field and deformation field of the surrounding rock during the service period of the compressed air gas storage reservoir reconstructed from the abandoned roadway after grouting reinforcement under the influence of different factors.

[0078] The initial damage of the surrounding rock is considered during the simulation. By partitioning the surrounding rock of the abandoned roadway and generating different fractures according to the property requirements of the surrounding rock in different areas of the abandoned roadway, and performing grouting simulation on the roadway containing fractures to obtain the contour map of its effective reinforcement range, the cost is reduced and the efficiency is improved. After grouting and reinforcing the abandoned roadway for compressed air energy storage, a numerical simulation of the thermal-mechanical coupling of the deterioration of the surrounding rock of the grouting-transformed abandoned roadway compressed air energy storage reservoir under the influence of different factors is carried out.

[0079] Embodiment 3:

[0080] A computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps in the above-mentioned method for simulating the stability of the surrounding rock of the abandoned roadway grouting-transformed compressed air energy storage reservoir are realized.

[0081] Embodiment 4:

[0082] A computer device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps in the above-mentioned method for simulating the stability of the surrounding rock of the abandoned roadway grouting-transformed compressed air energy storage reservoir are realized.

[0083] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A simulation method for surrounding rock stability of abandoned tunnel grouting transformation compressed gas energy storage reservoir, characterized in that: The following steps are involved: Determine the initial geomechanical conditions and the geological strength index values ​​of the destruction zone, damaged zone and disturbed zone around the compressed gas energy storage chamber; The simulation software is called to construct a three-dimensional solid model of the surrounding rock of the abandoned tunnel with random cracks using the material properties of different partitions. The obtained solid model is then simulated for the grouting diffusion range. The obtained simulation results are imported into the three-dimensional modeling software to obtain a gas storage model with grid lines and imported into the three-dimensional numerical analysis program. The creep damage model of fractured rock reinforced by grouting under cyclic pressure-storage-discharge gas disturbance is called and embedded into the three-dimensional numerical analysis program; Based on the three-dimensional numerical analysis program, under the influence of different factors, the evolution law of the stress field and deformation field of the surrounding rock of the compressed air storage after grouting reinforcement and abandoned tunnel reconstruction during service was numerically simulated and analyzed.

2. The surrounding rock stability simulation method for grouting and transforming compressed air energy storage reservoirs in abandoned tunnels as claimed in claim 1 is characterized in that: Determine the geological strength index values ​​of the destruction zone, damaged zone and disturbed zone around the compressed air energy storage chamber. Specifically, by sampling the rock mass in each partition and obtaining the joint spacing of the sample and the angle between the joint groups, calculate the block volume and joint condition factor, and determine the geological strength index value of the partition corresponding to each sample by table lookup method.

3. The surrounding rock stability simulation method for the abandoned tunnel grouting transformation compressed air energy storage reservoir as claimed in claim 1 is characterized in that: The simulation software is called and the material properties of different partitions are used to construct a three-dimensional solid model of the surrounding rock of the abandoned tunnel with random cracks. Specifically, the "Discrete Fracture Network-3D" plug-in in the simulation software is called to define the crack size, direction and attribute parameters of different areas in the destruction zone, damaged zone and disturbed zone, and generate a three-dimensional solid model of the surrounding rock of the abandoned tunnel with random cracks.

4. The surrounding rock stability simulation method for grouting and transforming compressed air energy storage reservoirs in abandoned tunnels as claimed in claim 1 is characterized in that: The obtained solid model is used to simulate the grouting diffusion range. Specifically, the Darcy's law interface in the porous media and groundwater flow modules under the fluid flow module in the simulation software is called to define different parameters for the destruction zone, damaged zone, disturbed zone and external surrounding rock. The grouting diffusion range is numerically simulated for the three-dimensional solid model of the surrounding rock of the abandoned tunnel containing random cracks.

5. The surrounding rock stability simulation method for the abandoned tunnel grouting transformation compressed air energy storage reservoir according to claim 1 is characterized in that: During the numerical simulation of the grouting diffusion range, the model was meshed according to the requirements of the Darcy's law interface, and the finite element method was used to transform the continuous physical field problem into a discrete set of algebraic equations. The numerical simulation results were obtained by discretizing and solving the Darcy equations.

6. The surrounding rock stability simulation method for grouting and transforming compressed air energy storage reservoirs in abandoned tunnels as claimed in claim 1 is characterized in that: The creep damage model of grouting reinforced cracked rock under cyclic pressure-storage-unloading gas disturbance is established. According to the experimental results and stress dissipation principle, the nonlinear viscoelastic mechanics element is used to replace the Newtonian viscoelastic in the Burgers creep model, and the nonlinear viscoplastic damage element is used to control the presence or absence of the unstable creep stage and describe the deformation characteristics of the unstable creep stage.

7. The surrounding rock stability simulation method for grouting and transforming compressed air energy storage reservoirs in abandoned tunnels as claimed in claim 1 is characterized in that: In the three-dimensional numerical analysis program, the Hoek-Brown constitutive model is used to describe the mechanical behavior of grouting-reinforced cracked rock. By writing the corresponding Fish function, the calculation logic of the creep damage model of grouting-reinforced cracked rock under cyclic pressure-storage-unloading gas disturbance is determined. The written Fish function is embedded in the gas storage model with grid lines, and the model is verified and calibrated by comparing with experimental data or actual engineering cases.

8. A surrounding rock stability simulation system for abandoned tunnel grouting transformation of compressed air energy storage reservoir, characterized in that: include: The initial condition module is configured to: determine the initial geomechanical conditions and determine the geological strength index values ​​of the destruction zone, the damaged zone and the disturbed zone around the compressed gas energy storage chamber; The grouting diffusion simulation module is configured to: call the simulation software, use the material properties of different partitions to build a three-dimensional solid model of the abandoned tunnel surrounding rock with random cracks, and simulate the grouting diffusion range of the obtained solid model, import the obtained simulation results into the three-dimensional modeling software, obtain the gas storage model with grid lines and import it into the three-dimensional numerical analysis program; The numerical simulation module is configured to: call the creep damage model of grouting reinforced cracked rock under cyclic pressure-storage-unloading gas disturbance and embed it into the three-dimensional numerical analysis program; Based on the three-dimensional numerical analysis program, under the influence of different factors, the evolution law of the stress field and deformation field of the surrounding rock of the compressed air storage after grouting reinforcement and abandoned tunnel reconstruction during service was numerically simulated and analyzed.

9. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the steps in the surrounding rock stability simulation method for grouting and transforming a compressed air energy storage reservoir into an abandoned tunnel as described in any one of claims 1 to 7 are implemented.

10. A computer device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps in the method for simulating the stability of surrounding rocks of a compressed air energy storage reservoir transformed by grouting in an abandoned tunnel are implemented as described in any one of claims 1 to 7.

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