Method and device for simulating rockburst through carbon dioxide fracturing pipe blasting

Abstract

The invention discloses a method and device for simulating rockburst through carbon dioxide fracturing pipe blasting, and relates to the technical field of computers. The method comprises the following steps: firstly, obtaining particle microcosmic parameters reflecting physical properties of a rock test piece, then carrying out a carbon dioxide fracturing pipe blasting test on the rock test piece, determining a distribution rule of blasting blocks in a blasting process, and then carrying out numerical simulation on the carbon dioxide fracturing pipe blasting test to obtain a simulation result. The method comprises the following steps: correcting particle mesoscopic parameters, constructing a first mapping relation between simulation parameters of explosion point particles in numerical simulation and parameters of the carbon dioxide fracturing pipe, finally simulating explosion of the carbon dioxide fracturing pipe under different explosion working conditions through numerical simulation, and matching real rockburst characteristics of different energy levels. And a second mapping relation between the simulation parameters of the blasting point particles and the rockburst energy levels is constructed, and the mapping relation between the parameters of the carbon dioxide fracturing pipe and the rockburst of different energy levels is determined by combining the first mapping relation and the second mapping relation. According to the invention, the simulation accuracy and safety of rockburst are improved.

Description

Technical Field

[0001] The present invention relates to the field of computer technology, and particularly relates to a method and device for simulating rock burst through blasting of carbon dioxide fracturing pipes. Background Art

[0002] Generally, during the construction of railway tunnels, the stability of tunnel excavation will be affected by complex geological environments. Among them, under high in-situ stress conditions, the dynamic instability phenomenon induced by brittle hard rock after excavation unloading is rock burst, which seriously affects the safe construction of tunnel excavation and poses significant potential safety hazards to life and property. Usually, the threat level of rock burst stones to the protection system can be determined through tests and targeted protection can be carried out.

[0003] Existing test methods are mainly divided into two categories. One is to equivalently simulate rock burst energy through drop ball tests on site. This is reliable for revealing the bearing performance of the protection system, but the regular shape of the drop ball is different from the real rock burst fragments, weakening the shear effect of the sharp surface of the rock, and there are also differences between the falling process of the drop ball under gravity and the sudden impact process of rock burst stones. The second is to restore the rock burst occurrence process through true triaxial model tests. To apply in-situ stress for this type of method, it is inevitable to scale down the tunnel for model tests.

[0004] In summary, existing rock burst simulation methods cannot accurately simulate the rock burst process on site. Summary of the Invention

[0005] Based on this, it is necessary to provide a method and device for simulating rock burst through blasting of carbon dioxide fracturing pipes in view of the above technical problems.

[0006] The present invention adopts the following technical solutions: The present invention provides a method for simulating rock burst through blasting of carbon dioxide fracturing pipes. First, obtain the particle mesoscopic parameters reflecting the physical properties of rock specimens, then conduct carbon dioxide fracturing pipe blasting tests on the rock specimens and determine the distribution law of fragments during the blasting process. After that, conduct multiple numerical simulations of carbon dioxide fracturing pipe blasting to correct the particle mesoscopic parameters, and at the same time construct the first mapping relationship between the simulation parameters of the blasting point particles in the numerical simulation and the carbon dioxide fracturing pipe parameters. Finally, simulate the carbon dioxide fracturing pipe blasting under different blasting conditions through numerical simulation, match the real rock burst characteristics of different energy levels, construct the second mapping relationship between the simulation parameters of the blasting point particles and the rock burst energy level, and determine the mapping relationship between the carbon dioxide fracturing pipe parameters and rock bursts of different energy levels according to the first mapping relationship and the second mapping relationship, so as to simulate rock burst through carbon dioxide fracturing pipe blasting on site.

[0007] The present invention provides a device for simulating rock burst through blasting of carbon dioxide fracturing pipes, including: A rock modeling module for obtaining particle mesoscopic parameters reflecting the physical properties of rock specimens; A blasting test module for conducting a carbon dioxide fracturing pipe blasting test on a rock specimen and determining the distribution law of fragments during blasting; A simulated blasting module for using the discrete element method to equivalent the carbon dioxide fracturing pipe to blasting point particles, conducting multiple simulations of the carbon dioxide fracturing pipe blasting to correct the particle mesoscopic parameters until the fragment distribution law is restored; and determining the first mapping relationship between the simulation parameters of the blasting point particles and the carbon dioxide fracturing pipe parameters; A matching module for using the discrete element method to simulate the blasting process under different blasting conditions according to the corrected particle mesoscopic parameters and blasting point particles with different simulation parameters, matching the real rock burst characteristics at different energy levels, and constructing the second mapping relationship between the simulation parameters of the blasting point particles and the rock burst energy level; A simulated rock burst mapping module for determining the mapping relationship between the carbon dioxide fracturing pipe parameters and rock bursts at different energy levels according to the first mapping relationship and the second mapping relationship, so as to simulate rock bursts on-site through the blasting of carbon dioxide fracturing pipes.

[0008] The present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the method for simulating rock bursts through the blasting of carbon dioxide fracturing pipes as described above is implemented.

[0009] 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, and when the processor executes the program, the method for simulating rock bursts through the blasting of carbon dioxide fracturing pipes as described above is implemented.

[0010] The above at least one technical solution adopted by the present invention can achieve the following beneficial effects: The impact process of fragments after the blasting of carbon dioxide fracturing pipes is relatively similar to that of rock bursts. However, if physical tests are used to explore how the blasting of carbon dioxide fracturing pipes accurately simulates rock bursts, there are safety risks and high costs.

[0011] The present invention takes a single blasting test of a carbon dioxide fracturing tube as a benchmark, accurately simulates the blasting test of the carbon dioxide fracturing tube by using the particle flow discrete element modeling method, corrects the particle mesoscopic parameters reflecting the physical properties of the rock specimen through multiple simulations, and determines the mapping relationship between the simulation parameters of the blasting point particles and the parameters of the carbon dioxide fracturing tube. Then, based on the corrected particle mesoscopic parameters, the blasting process under different blasting conditions is simulated, and the real rock burst characteristics of different energy levels are matched. The mapping relationship between the carbon dioxide fracturing tube blasting and the rock burst is accurately connected through the numerical simulation process, so as to obtain the mapping relationship between the accurate carbon dioxide fracturing tube parameters and the rock bursts of different energy levels, and thus carry out the carbon dioxide fracturing tube blasting on the spot to accurately simulate the rock burst of the target energy level.

[0012] Through the physical blasting test and blasting numerical simulation of the carbon dioxide fracturing tube, the present invention restores the real rock burst stone ejection phenomenon at the laboratory scale, determines the mapping relationship between the carbon dioxide fracturing tube parameters and the rock bursts of different energy levels through fewer physical tests for application in on-site rock burst simulation, thereby improving the accuracy of on-site rock burst simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part 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 to the present invention. In the drawings: Figure 1 It is a schematic flow chart of a method for simulating rock burst by carbon dioxide fracturing tube blasting provided by the present invention; Figure 2 It is a schematic diagram of discrete element modeling of a rock sample provided by the present invention; Figure 3 It is a schematic diagram of a carbon dioxide fracturing tube blasting test provided by the present invention; Figure 4 It is a schematic diagram of numerical simulation of carbon dioxide fracturing tube blasting provided by the present invention; Figure 5 It is a schematic diagram of a blasting stress wave provided by the present invention; Figure 6 It is a schematic diagram of the phenomenon of explosive block ejection during carbon dioxide fracturing tube blasting provided by the present invention; Figure 7 It is a schematic diagram of a device for simulating rock burst by carbon dioxide fracturing tube blasting provided by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0015] At present, there is a large difference between the equivalent rockburst energy and the real rockburst fragments through the falling ball test on site, while conducting tests through models will make it difficult to construct the components (such as bolts, protective nets, etc.) of the rockburst protection system on the models, and it is impossible to detect the bearing performance of the rockburst protection system.

[0016] To verify the threat level of rockburst stones to the protection system in the laboratory, the idea of the present invention is to use a carbon dioxide fracturing pipe to apply an impact load to the rock to restore the throwing phenomenon of rockburst stones. However, since this field is still blank at present, there is no clear mapping relationship between the dosage and installation position of the carbon dioxide fracturing pipe and the kinetic energy of the stones under different rockburst energy levels. Moreover, exploring the mapping relationship between the two through multi-condition physical blasting tests will bring problems such as increased test costs, high safety risks, and large human input.

[0017] The following will detail the technical solutions provided by each embodiment of the present invention in conjunction with the drawings.

[0018] Figure 1 The following is a schematic flow chart of a method for simulating rockburst by blasting with a carbon dioxide fracturing pipe in the present invention, which specifically includes the following steps: S101: Obtain the particle mesoscopic parameters reflecting the physical properties of the rock specimen.

[0019] S102: Conduct a carbon dioxide fracturing pipe blasting test on the rock specimen and determine the distribution law of the fragments during the blasting process.

[0020] S103: Adopt the discrete element method to equivalent the carbon dioxide fracturing pipe to explosive point particles, conduct multiple simulations of the carbon dioxide fracturing pipe blasting to correct the particle mesoscopic parameters until the distribution law of the fragments is restored; and determine the first mapping relationship between the simulation parameters of the explosive point particles and the parameters of the carbon dioxide fracturing pipe.

[0021] S104: Adopt the discrete element method to simulate the blasting process under different blasting conditions according to the corrected particle mesoscopic parameters and the explosive point particles with different simulation parameters, match the real rockburst characteristics at different energy levels, and construct the second mapping relationship between the simulation parameters of the explosive point particles and the rockburst energy level.

[0022] S105: Determine the mapping relationship between the parameters of the carbon dioxide fracturing pipe and rock bursts of different energy levels according to the first mapping relationship and the second mapping relationship, so as to simulate rock bursts through carbon dioxide fracturing pipe blasting on site.

[0023] Generally, for situations where there are risks in physical experiments, a certain degree of simulation can be considered through numerical simulation, thereby reducing the number of real physical experiments. Among them, how to conduct numerical simulation determines whether the numerical simulation can accurately reflect the physical experiment situation.

[0024] Based on this, in one or more embodiments of the present invention, particle flow discrete element modeling is used to numerically simulate the rocks in the construction area. Particle flow is a discrete element method that simulates the macroscopic mechanical properties of materials through the interaction between circular particles. Since in discrete element numerical simulation, the macroscopic physical and mechanical parameters corresponding to the numerical model and the particle mesoscopic parameters are generally not in one-to-one correspondence, specifically, the present invention can first conduct uniaxial compression tests and Brazilian splitting tests on rock samples respectively to obtain the pressure stress-strain curve and tensile stress-strain curve of the rock samples as the real test results. Then, use particle flow to perform scaled discrete element modeling on the rock samples, and assign initial mesoscopic parameters to each particle to obtain an initial rock simulation sample. Then, determine the pressure stress-strain curve and tensile stress-strain curve corresponding to the numerical simulation test results of the initial rock simulation sample, and correct the initial mesoscopic parameters according to the deviation between the numerical simulation test results of the rock simulation sample and the real test results of the rock sample. Finally, through multiple rounds of iterative correction, make the numerical simulation test results match the real test results to obtain multiple groups of initial particle mesoscopic parameters reflecting the physical properties of the rock samples.

[0025] Since each group of initial particle mesoscopic parameters includes multiple mesoscopic parameters, multiple groups of initial particle mesoscopic parameters are different combinations of multiple mesoscopic parameters, and each combination may be able to meet the purpose of making the numerical simulation test results match the real test results, so each group of initial particle mesoscopic parameters can be retained, and multiple groups of initial particle mesoscopic parameters can be screened through the blasting simulation process later to obtain better final particle mesoscopic parameters.

[0026] For example, first obtain the rock samples corresponding to the rock specimens. The uniaxial compression test and the Brazilian splitting test can be sampled separately. Among them, the diameter of the uniaxial compression specimen can be 50 mm, and the height can be 100 mm. The diameter of the Brazilian splitting specimen can be 50 mm, and the height can be 25 mm.

[0027] By conducting uniaxial compression tests and Brazilian splitting tests on rock samples separately, the pressure stress-strain curve and tensile stress-strain curve can be obtained. Then, a particle flow discrete element model with a scaled ratio can be established. The rock sample is composed of circular particles, and appropriate particle mesoscopic parameters are assigned to the particle contacts. A load is applied to the wall element, such as Figure 2 shown Figure 2 which is a schematic diagram of the discrete element modeling of a rock sample in the present invention. Figure 2 On the left side in it is the schematic of the uniaxial compression test of the rock sample, and on the right side is the schematic of the Brazilian splitting test of the rock sample. For the calibration of particle mesoscopic parameters, the "trial and error method" can be used to calibrate various parameters of the rock sample.

[0028] For example, first, keep the stiffness ratio (kratio) and the internal friction angle unchanged, and adjust the particle contact modulus (emod) and the parallel bond modulus (pb_emod) to control the macroscopic compressive elastic modulus. Secondly, control the Poisson's ratio through the stiffness ratio. For the change of the elastic modulus in this process, repeated iteration is used to achieve a reasonable elastic modulus and Poisson's ratio. Finally, for the internal friction angle and cohesion of the rock, they can be controlled by adjusting the parallel bond normal strength (pb_ten) and the tangential strength (pb_coh) to make the pressure stress-strain curve and the tensile stress-strain curve as close as possible to the real test curve. Ultimately, through restoring the indoor test of the rock sample, the uniaxial compression and Brazilian splitting numerical simulations are completed, and multiple groups of initial particle mesoscopic parameters that can better reflect the physical properties of the rock are obtained.

[0029] After that, a blasting test of a carbon dioxide fracturing tube can be carried out based on a preset-sized rock specimen with the same physical properties as the rock sample.

[0030] For example, a rock specimen with an overall size of 1.2m×1.2m×1.2m can be prefabricated, and a circular hole with a diameter of 60mm and a depth of 800mm can be prefabricated above the rock specimen to facilitate the installation of the carbon dioxide fracturing tube, such as Figure 3 shown Figure 3 which is a schematic diagram of a blasting test of a carbon dioxide fracturing tube in the present invention. Figure 3 On the left side in it is the schematic of the carbon dioxide fracturing tube blasting the rock specimen, and on the right side (a)-(d) are the schematic diagrams of the process of the carbon dioxide fracturing tube blasting the rock specimen.

[0031] After the rock specimens are processed, they can be moved to the blasting site. When prefabricating the rock specimens, 0.7 L of liquid carbon dioxide is filled into each carbon dioxide fracturing tube. After sealing, carry the carbon dioxide fracturing tubes to the blasting site. For the rock specimens with the size of 1.2 m × 1.2 m × 1.2 m, place the side with the prefabricated circular hole upward, and the air release port of the fracturing tube is located at the bottom of the hole. Place the carbon dioxide fracturing tube in the prefabricated hole of the rock specimen, and seal the hole with quick-drying cement to prevent the tube from flying out. After installing the carbon dioxide fracturing tube, relevant personnel retreat to a safe distance to detonate the carbon dioxide fracturing tube for the full free-face blasting test.

[0032] In one or more embodiments of the present invention, a high-speed camera can be used to record the blasting process. Based on the motion capture function of the high-speed camera, the blasted blocks are captured to obtain the ejection images of the blasted blocks. Subsequently, the ejection images of the blasted blocks collected during the blasting process can be obtained, the ejection speed of each blasted block is determined, and combined with the size of each blasted block and the distance of each blasted block from the target position, the speed distribution law of each blasted block is determined.

[0033] For the block distribution law of the blasted blocks, the fractal dimension can be calculated according to the blasted blocks after the rock specimen is broken. The blasted blocks after blasting can be divided into multiple levels according to the fragmentation size. For example, the side lengths of the blasted blocks after blasting are screened according to 0.5 m, 0.25 m, 0.1 m, 0.05 m, 0.02 m, 0.01 m, and 0.005 m. The mass of the blasted blocks corresponding to each level of fragmentation size can be determined by a high-precision balance. To quantify the distribution characteristics of each level of fragmentation size, the fragmentation size distribution law of each blasted block can be determined according to the mass-size relationship: .

[0034] In the formula, is the fragmentation size, is the cumulative mass of the blasted blocks with a fragmentation size less than , is the total mass of each blasted block, is the fractal dimension of the fragmentation size distribution of each blasted block.

[0035] The logarithm of the fragmentation size distribution of each blasted block can also be taken: , and with as the abscissa, as the ordinate, as the slope of the fitting curve, the mass fractal dimension of each blasted block is obtained.

[0036] Next, according to the physical blasting test, numerical simulation of the blasting of the carbon dioxide fracturing pipe can be carried out. Specifically, in one or more embodiments of the present invention, the rock specimen can be simulated by particle flow according to the initial particle mesoscopic parameters, and a rock simulation specimen with the same size as the rock specimen can be constructed. And at the position where the carbon dioxide fracturing pipe is set relative to the rock specimen in the rock simulation specimen, blasting points are simulated by using blasting point particles with the same diameter as the carbon dioxide fracturing pipe. Then, the blasting impact force is formed by the superposition of the expansion of the blasting point particles on the granular bodies representing the rock mass around the blasting point, so as to equivalent the carbon dioxide fracturing pipe to the blasting point particles, simulate the blasting process of the carbon dioxide fracturing pipe, and determine the velocity distribution law, fragmentation size distribution law and mass fractal dimension of each blasting block during the simulated blasting process as the distribution law of each blasting block during the simulated blasting process.

[0037] For example, the discrete element method (DEM) can be used to generate a rock simulation specimen with a size of 1.2m×1.2m×1.2m. The particle mesoscopic parameters between particles are any one group of the initial particle mesoscopic parameters obtained above. The bottom is simulated by a wall, and the blasting point is set at the same position as the physical test, such as Figure 4 shown Figure 4 is a schematic diagram of the numerical simulation of the blasting of a carbon dioxide fracturing pipe in the present invention. The central circular particle represents the blasting point particle. The initial diameter of the blasting point particle is the same as the diameter of the carbon dioxide fracturing pipe. A measuring circle is set around the blasting point particle. Through the expansion of the blasting point particle, a superposition amount is generated on the granular bodies of the surrounding rock to form a blasting impact force.

[0038] The blasting of the carbon dioxide fracturing pipe can be approximately regarded as spreading outward in the form of a spherical wave from the vent hole, and it is equivalent to a pulse stress wave in the particle flow. The pressure action on the hole wall can be divided into a half-sine wave with the same increase and decrease time: , such as Figure 5 shown Figure 5 is a schematic diagram of a blasting stress wave in the present invention.

[0039] In the formula, is the peak pressure in the hole at the target position, is the pressure action time, is the duration time, is the gas pressure. According to the peak pressure and action time of the high-pressure gas of the carbon dioxide fracturing pipe in the cavity, the change trend of the acting force of the carbon dioxide fracturing pipe blasting process on the rock inner wall can be obtained.

[0040] In terms of numerical simulation, the carbon dioxide fracturing pipe can be simulated by the expansion of the blasting point particles according to the following formula: .

[0041] In the formula, is the radius expansion of the explosion point particles, is the contact stiffness between particles of the rock simulation specimen, is the initial diameter of the explosion point particles, is the simulated hole explosion pressure for the blasting of the carbon dioxide fracturing pipe.

[0042] According to the particle contact principle, the initial diameter of the explosion point particles is determined as r , fix the position of the explosion point, increase the radius of the explosion particles. After expansion, the explosion point particles contact the rock particles and transfer pressure to the adjacent particles, thereby generating a radial thrust on the surrounding rock particles. Given the initial radius of the explosion point particles, the contact stiffness between particles, and the explosion pressure, the blasting of the carbon dioxide fracturing pipe can be simulated by the change in the radius of the explosion point particles.

[0043] As long as the particles in the rock simulation specimen change according to , the action of the blasting load on the periphery of the rock mass borehole can be simulated. When the explosion point particles expand, a shock wave is generated on the particles around the explosion point particles in the rock simulation specimen. A crushed zone is formed under radial compression and decays into a stress wave after crushing the rock simulation specimen, generating a tensile stress on the surface of the rock simulation specimen, causing the rock simulation specimen to rupture and form cracks, as Figure 6 shown. Figure 6 This is a schematic diagram of the projectile ejection phenomenon during the blasting of a carbon dioxide fracturing pipe in the present invention. Figure 6 On the left side in is the numerical simulation schematic of the expanded blasting rock sample, and on the right side is the numerical simulation schematic of the projectile ejection of the rock. After the simulation is completed, according to the pre-set measurement circle and the velocity, block distribution, and fractal dimension of the stone projectile obtained from post-processing, the numerical simulation results are compared with the physical test results. If the restoration of the ejected stones is good, it proves the accuracy of the numerical simulation model; if there are significant differences between the numerical simulation results and the physical test, the initial particle mesoscopic parameters need to be adjusted and the simulation is carried out again until the phenomena are basically the same (the final particle mesoscopic parameters can be selected from multiple groups of initial particle mesoscopic parameters to make the blasting simulation consistent with the blasting test results), thereby constructing the first mapping relationship between the simulation parameters (expansion radius and layout position) of the explosion point particles and the parameters of the carbon dioxide fracturing pipe, and obtaining a blasting simulation model that can accurately simulate the blasting of the carbon dioxide fracturing pipe based on the physical properties of the rock in the construction area.

[0044] Further, in one or more embodiments of the present invention, after verifying the reliability of the numerical simulation of the blasting of the carbon dioxide fracturing pipe through the above method, numerical simulations of blasting under different working conditions can be set. The different blasting working conditions include different blasting points and different blasting energies, and different blasting energies correspond to different simulated hole explosion pressures. The peak pressure of carbon dioxide in the carbon dioxide fracturing pipe is represented by the radius expansion of the blasting point particles, and the arrangement position of the blasting point particles represents the installation position of the air outlet of the carbon dioxide fracturing pipe inside the rock.

[0045] Table 1 Numerical simulation of carbon dioxide fracturing pipe blasting under different working conditions

[0046] For example, the peak pressures can be set to 150 MPa, 200 MPa, 250 MPa, and 300 MPa respectively, and the blasting positions can be set to (0.6 m, 0.6 m, 0.2 m), (0.6 m, 0.6 m, 0.3 m), (0.6 m, 0.6 m, 0.4 m), (0.6 m, 0.6 m, 0.5 m) respectively. A numerical simulation experiment with multi-condition control variables is set up, as shown in Table 1.

[0047] After the experiment is completed, the numerical simulation results under different working conditions are recorded by measuring circles. According to the numerical simulation results, the corresponding relationships between the blasting pressure, blasting position, block ejection velocity, and fractal dimension are obtained, and the distribution law of blasted blocks and ejection velocity after rock mass blasting are statistically analyzed.

[0048] During the simulation process, the second mapping relationship between the simulation parameters of the blasting point particles and the rockburst energy level can be constructed by combining real rockburst cases with different energy levels.

[0049] Rockburst is a dynamic phenomenon in which the elastic strain energy accumulated in the rock mass suddenly releases under engineering disturbances, resulting in the bursting and ejection of the surrounding rock. The main harm of rockburst is the threat of the kinetic energy of the blasted blocks to construction personnel and machinery. Restoring the phenomenon of blasted block ejection in tunnel rockburst dynamic disasters is of great significance for preventing and controlling rockburst disasters. Due to the different lithology, strength, and integrity of the surrounding rock, there are also large differences in the volume and velocity of the ejected stones. According to the current rockburst energy level classification, the velocity and range of rockburst stones under different energy levels are shown in Table 2.

[0050] Table 2 Typical characteristics of different rockburst energy levels

[0051] Compare the numerical simulation results of the blasting of carbon dioxide fracturing pipes with real rock burst cases, find the most representative distribution of ejected rock fragments in each energy level of rock burst, establish the mapping relationship between the expansion radius and the layout position of the blasting point particles and the rock burst energy level, and then obtain the parameters of the carbon dioxide fracturing pipes in the physical blasting test of carbon dioxide fracturing pipe blasting according to the expansion radius and the layout position of the blasting point particles, so as to achieve the purpose of restoring the dynamic disaster of real rock burst disasters through the blasting of carbon dioxide fracturing pipes to simulate rock burst on site.

[0052] Based on Figure 1 For the method of simulating rock burst by blasting carbon dioxide fracturing pipes as shown, first obtain the particle mesoscopic parameters reflecting the physical properties of the rock specimen, then conduct a carbon dioxide fracturing pipe blasting test on the rock specimen and determine the distribution law of the rock fragments during the blasting process. After that, conduct multiple numerical simulations of the carbon dioxide fracturing pipe blasting to correct the particle mesoscopic parameters, and at the same time construct the first mapping relationship between the simulation parameters of the blasting point particles and the carbon dioxide fracturing pipe parameters in the numerical simulation. Finally, simulate the carbon dioxide fracturing pipe blasting under different blasting conditions through numerical simulation, match the real rock burst characteristics of different energy levels, construct the second mapping relationship between the simulation parameters of the blasting point particles and the rock burst energy level, and determine the mapping relationship between the carbon dioxide fracturing pipe parameters and the rock burst of different energy levels according to the first mapping relationship and the second mapping relationship, so as to simulate rock burst on site through the blasting of carbon dioxide fracturing pipes.

[0053] The impact process of the blasting of carbon dioxide fracturing pipes and the rock fragments after rock burst is relatively similar. However, if we explore how to accurately simulate rock burst through physical experiments, there are safety risks and high costs for the blasting of carbon dioxide fracturing pipes.

[0054] The present invention takes a single carbon dioxide fracturing pipe blasting test as a benchmark, uses the particle flow discrete element modeling method to accurately simulate the carbon dioxide fracturing pipe blasting test, corrects the particle mesoscopic parameters reflecting the physical properties of the rock specimen through multiple simulations, and at the same time determines the mapping relationship between the simulation parameters of the blasting point particles and the carbon dioxide fracturing pipe parameters. Then, based on the corrected particle mesoscopic parameters, simulate the blasting process under different blasting conditions, match the real rock burst characteristics of different energy levels, and accurately connect the mapping relationship between the carbon dioxide fracturing pipe blasting and the rock burst through the numerical simulation process, so as to obtain the accurate mapping relationship between the carbon dioxide fracturing pipe parameters and the rock burst of different energy levels, and thus carry out the carbon dioxide fracturing pipe blasting on site to accurately simulate the rock burst of the target energy level.

[0055] Through physical blasting tests of carbon dioxide fracturing pipes and blasting numerical simulations, the present invention restores the real rock burst stone ejection phenomenon at the laboratory scale, determines the mapping relationship between the carbon dioxide fracturing pipe parameters and different energy levels of rock bursts through fewer physical tests for application in on-site rock burst simulations, thereby improving the accuracy of on-site rock burst simulations.

[0056] When it is necessary to simulate a rock burst of a certain energy level, the carbon dioxide fracturing pipe blasting can be directly carried out on-site through the corresponding carbon dioxide fracturing pipe parameters for rock burst simulation. This can not only accurately simulate the rock burst to determine the threat degree of the rock burst stones to the protection system, but also reduce the number of physical blasting tests, and lower the safety risk and cost.

[0057] When applying the method for simulating rock bursts by carbon dioxide fracturing pipe blasting provided by the present invention, it is not necessary to execute according to Figure 1 the sequence of the steps shown. The specific execution sequence of each step can be determined according to needs, and the present invention does not limit this.

[0058] The above is the method for simulating rock bursts by carbon dioxide fracturing pipe blasting provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding device for simulating rock bursts by carbon dioxide fracturing pipe blasting, as Figure 7 shown.

[0059] Figure 7 The figure is a schematic diagram of a device for simulating rock bursts by carbon dioxide fracturing pipe blasting provided by the present invention, including: A rock modeling module 201 for obtaining the particle mesoscopic parameters reflecting the physical properties of the rock specimen, where the rock specimen is used for blasting to simulate rock bursts; A blasting test module 202 for conducting carbon dioxide fracturing pipe blasting tests on the rock specimen; A simulated blasting module 203 for using the discrete element method to equivalent the carbon dioxide fracturing pipe to a blasting point particle, conducting multiple simulations of the carbon dioxide fracturing pipe blasting to correct the particle mesoscopic parameters until the distribution law of the blasted blocks is restored; and determining the first mapping relationship between the simulation parameters of the blasting point particle and the carbon dioxide fracturing pipe parameters; A matching module 204 for using the discrete element method to simulate the blasting process under different blasting conditions according to the corrected particle mesoscopic parameters and the blasting point particles with different simulation parameters, and matching the real rock burst characteristics of different energy levels to construct the second mapping relationship between the simulation parameters of the blasting point particle and the rock burst energy level; A simulated rock burst mapping module 205 for determining the mapping relationship between the carbon dioxide fracturing pipe parameters and different energy levels of rock bursts according to the first mapping relationship and the second mapping relationship, so as to simulate rock bursts by carbon dioxide fracturing pipe blasting on-site.

[0060] For the specific limitations of the device for simulating rockburst by blasting with a carbon dioxide fracturing pipe, reference may be made to the limitations of the method for simulating rockburst by blasting with a carbon dioxide fracturing pipe in the foregoing text, which will not be elaborated herein. Each module in the above device for simulating rockburst by blasting with a carbon dioxide fracturing pipe can be implemented in whole or in part by software, hardware, and their combination. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or stored in the memory of the computer device in the form of software, so as to facilitate the processor to call and execute the operations corresponding to the above modules.

[0061] The present invention also provides a computer-readable storage medium storing a computer program, which can be used to execute the above Figure 1 method for simulating rockburst by blasting with a carbon dioxide fracturing pipe provided.

[0062] The present invention also provides a computer device. At the hardware level, the computer device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory. Of course, other hardware required for other services may also be included. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to implement the above Figure 1 method for simulating rockburst by blasting with a carbon dioxide fracturing pipe provided.

[0063] Those of ordinary skill in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above method embodiments. Among them, any reference to the memory, storage, database, or other media used in the various embodiments provided by the present invention can include at least one of non-volatile and volatile memories. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical memory, etc. The volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0064] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope recorded by the present invention.

Claims

1. A method for simulating rockburst by blasting a carbon dioxide fracturing pipe, characterized in that, Including: Obtaining particle mesoscopic parameters reflecting the physical properties of rock specimens; Conducting a blasting test on a rock specimen using a carbon dioxide fracturing pipe and determining the distribution law of blasted blocks during the blasting process; Adopting the discrete element method, equivalent the carbon dioxide fracturing pipe to blasting point particles, conduct multiple simulations of the carbon dioxide fracturing pipe blasting to correct the particle mesoscopic parameters until the distribution law of the blasted blocks is restored; and determine the first mapping relationship between the simulation parameters of the blasting point particles and the parameters of the carbon dioxide fracturing pipe; Adopting the discrete element method, according to the corrected particle mesoscopic parameters and blasting point particles with different simulation parameters, simulate the blasting process under different blasting conditions, and match the real rock burst characteristics of different energy levels, and construct the second mapping relationship between the simulation parameters of the blasting point particles and the rock burst energy level; According to the first mapping relationship and the second mapping relationship, determine the mapping relationship between the parameters of the carbon dioxide fracturing pipe and rock bursts of different energy levels, so as to simulate rock bursts through the carbon dioxide fracturing pipe blasting on site.

2. The method for simulating rock burst by blasting of carbon dioxide fracturing pipes according to claim 1, characterized in that, The determination of the distribution law of the blasted blocks during the blasting process specifically includes: Obtaining the ejected images of the blasted blocks collected during the blasting process and determining the ejection speed of each blasted block; combining the size of each blasted block and the distance of each blasted block from the target position to determine the speed distribution law of each blasted block; After blasting, the blasted blocks are divided into multiple levels according to the fragmentation size, and the cumulative mass of the blasted blocks corresponding to each level of fragmentation size is determined. The fragmentation size distribution law of each blasted block is determined by the following formula: ; Take the logarithm of the fragmentation size distribution of each blasted block: , and use as the abscissa, as the ordinate, as the slope of the fitting curve to obtain the mass fractal dimension of each blasted block; Among them, is the fragmentation size, is the cumulative mass of the blasted blocks with fragmentation size less than , is the total mass of each blasted block, is the fractal dimension of the fragmentation size distribution of each blasted block.

3. The method for simulating rock burst by blasting of carbon dioxide fracturing pipes according to claim 1, characterized in that, The adoption of the discrete element method, equivalent the carbon dioxide fracturing pipe to blasting point particles, and conduct multiple simulations of the carbon dioxide fracturing pipe blasting specifically includes: Simulate the rock specimen with particle flow according to the particle mesoscopic parameters to construct a rock simulation specimen of the same size as the rock specimen; At the position where the carbon dioxide fracturing pipe is set relative to the rock specimen in the rock simulation specimen, set blasting point particles with the same diameter as the carbon dioxide fracturing pipe; Generate a superimposed amount on the particle bodies representing the rock mass around the blasting point through the expansion of the blasting point particles to form a blasting impact force, so as to equivalent the carbon dioxide fracturing pipe to blasting point particles and simulate the blasting process of the carbon dioxide fracturing pipe; Determine the speed distribution law, fragmentation size distribution law and mass fractal dimension of each blasted block during the simulated blasting process as the distribution law of each blasted block during the simulated blasting process.

4. The method for simulating rock burst by blasting of carbon dioxide fracturing pipes according to claim 3, characterized in that, The generation of a superimposed amount on the particle bodies representing the rock mass around the blasting point through the expansion of the blasting point particles to form a blasting impact force, so as to equivalent the carbon dioxide fracturing pipe to blasting point particles and simulate the blasting process of the carbon dioxide fracturing pipe specifically includes: The blasting of the carbon dioxide fracturing pipe is simulated based on the expansion of the blasting point particles according to the following formula: ; When the blasting point particles expand, generate shock waves on the particles around the blasting point particles in the rock simulation specimen, form a crushed zone under radial compression, and attenuate into stress waves after crushing the rock simulation specimen, generate tensile stress on the surface of the rock simulation specimen, and cause the rock simulation specimen to crack and form cracks; Among them, is the radius expansion amount of the detonation point particles, is the inter-particle contact stiffness of the rock simulation specimen, is the initial diameter of the detonation point particles, is the simulated hole explosion pressure for the blasting of the carbon dioxide fracturing pipe.

5. The method for simulating rock burst by blasting of carbon dioxide fracturing pipe according to claim 4, characterized in that, The different blasting conditions include different blasting points and different blasting energies; the different blasting energies correspond to different simulated hole explosion pressures.

6. The method for simulating rock burst by blasting of carbon dioxide fracturing pipes according to claim 1, characterized in that The obtaining of the particle mesoscopic parameters reflecting the physical properties of the rock specimen specifically includes: Obtaining the rock samples corresponding to the rock specimens, respectively conducting uniaxial compression tests and Brazilian splitting tests on the rock samples, and obtaining the pressure stress-strain curve and tensile stress-strain curve of the rock samples as the real test results; Perform scaled discrete element modeling of a rock sample with particle flow, and assign initial mesoscopic parameters to each particle to obtain an initial rock simulation sample; Determine the pressure stress-strain curve and tensile stress-strain curve corresponding to the numerical simulation test results of the initial rock simulation sample, and correct the initial mesoscopic parameters according to the deviation between the numerical simulation test results of the rock simulation sample and the real test results of the rock sample; Through multiple rounds of iterative correction, make the numerical simulation test results match the real test results, and obtain the particle mesoscopic parameters reflecting the physical properties of the rock sample.

7. A device for simulating rock burst by blasting a carbon dioxide fracturing pipe, characterized in that, It includes: A rock modeling module for obtaining particle mesoscopic parameters reflecting the physical properties of a rock specimen; A blasting test module for conducting a carbon dioxide fracturing pipe blasting test on a rock specimen and determining the distribution law of blasting blocks during the blasting process; A simulated blasting module for using the discrete element method to equivalent the carbon dioxide fracturing pipe to a blasting point particle, conducting multiple simulations of the carbon dioxide fracturing pipe blasting to correct the particle mesoscopic parameters until the distribution law of the blasting blocks is restored; and determining the first mapping relationship between the simulation parameters of the blasting point particle and the carbon dioxide fracturing pipe parameters; A matching module for using the discrete element method to simulate the blasting process under different blasting conditions according to the corrected particle mesoscopic parameters and blasting point particles with different simulation parameters, and matching the real rock burst characteristics at different energy levels to construct the second mapping relationship between the simulation parameters of the blasting point particle and the rock burst energy level; A simulated rock burst mapping module for determining the mapping relationship between the carbon dioxide fracturing pipe parameters and rock bursts at different energy levels according to the first mapping relationship and the second mapping relationship, so as to simulate rock bursts on-site through carbon dioxide fracturing pipe blasting.

8. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, and when the computer program is executed by a processor, the method described in any one of claims 1 to 6 is implemented.

9. A computer device, characterized in that, It 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 method described in any one of claims 1 to 6 is implemented.

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