Numerical simulation and inversion analysis method for single open face rock plug blasting

Abstract

A numerical simulation inversion analysis method for single-face rock plug blasting is disclosed. The method numerically simulates, inverts and analyzes the single-face rock plug blasting by building an inversion analysis model, selecting inversion analysis parameters and performing numerical simulation inversion analysis calculations. The inversion analysis model is built using the ABAQUS / Explicit platform, including a blasting parameter preliminary selection test model, a blasting parameter optimization test model and a through blasting test model. The inversion analysis parameter selection includes calculation parameter selection and initial geostress selection. The numerical simulation inversion analysis calculation includes a blasting parameter preliminary selection test, a blasting parameter optimization test and a through blasting test. Finally, the kinetic energy time history in the through blasting test is obtained to determine whether the steep increase moment in the curve corresponds to the delay time of the blasting network.

Description

Technical Field

[0001] The invention belongs to the technical field of rock plug blasting seismic effect analysis, and relates to a numerical simulation inversion analysis method for single-face rock plug blasting. Background Art

[0002] The strata at the rock plug are granites of the Yaliang unit (K1y) in the late Yanshan period, intercalated with diabase veins. The cover layer of the rock plug is scattered, with a thickness of 1.0m to 1.1m, mainly weakly to slightly weathered granites, with a weakly weathered thickness of about 1.0m to 5.2m, and the rest are slightly weathered, which belongs to favorable geological conditions. The weakly weathered rocks are relatively complete as a whole, weakly permeable, and have a certain self-stabilizing ability.

[0003] Rock plug blasting is usually divided into single-face and double-face. The mechanical environment of the two is very different under different conditions. The detonation network of rock plug blasting is complex, with many processes and long blasting operation time. Under normal circumstances, it takes several days. This puts extremely strict requirements on the performance of blasting equipment, including water-resistant explosives, detonating cords, non-electric high-precision detonating cord detonators, etc.

[0004] In view of the complex influencing factors of single-face rock plug blasting construction, the rock mass physical parameters and explosive performance parameters initially selected in the early stage of prediction analysis are very different from the actual situation, and the material parameters in the geological survey report cannot be directly applied to the tensile damage constitutive structure. Therefore, in order to determine the tensile failure threshold of the surrounding rock under the real natural stress state, it is necessary to perform simulation inversion analysis on the blasting values. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a numerical simulation inversion analysis method for single-faced rock plug blasting, which adopts the methods of building an inversion analysis model, selecting inversion analysis parameters and performing numerical simulation inversion analysis calculation to perform numerical simulation, inversion and analysis on single-faced rock plug blasting. The inversion analysis model is built using the ABAQUS / Explicit platform, including a blasting parameter preliminary selection test model, a blasting parameter optimization test model and a through blasting test model. The inversion analysis parameter selection includes calculation parameter selection and initial ground stress selection. The numerical simulation inversion analysis calculation includes a blasting parameter preliminary selection test, a blasting parameter optimization test and a through blasting test. Finally, the kinetic energy time course in the through blasting test is obtained, and it is judged whether the steep increase moment in the curve corresponds to the delay time of the detonation network.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a numerical simulation inversion analysis method for single-face rock plug blasting, which comprises the following steps:

[0007] Step 1: Establish an inversion analysis model, using the ABAQUS / Explicit platform to establish a blasting parameter preliminary selection test model, a blasting parameter optimization test model, and a through blasting test model;

[0008] Step 2, inversion analysis parameter selection, including calculation parameter selection and initial geostress selection;

[0009] Step 3: numerical simulation inversion analysis and calculation, including blasting parameter preliminary selection test, blasting parameter optimization test and through-blasting test.

[0010] In step 2, the explosive material is described by the JWL state equation, and the basic physical parameters of the explosive are obtained by referring to the test results of blasting equipment, that is, the JWL state equation parameter table of explosives, and combined with the blasting parameter preliminary selection test and the blasting parameter optimization test, after repeated calculations, the material parameters that can fully reflect the results of the above two tests are finally obtained, that is, the basic parameter table of the surrounding rock constitutive model; according to the blasting test design, the detonation time of each hole and the coordinates of the detonation points at the hole mouth and the hole bottom are set.

[0011] In step 2, when selecting the calculation parameters, Rayleigh damping is used, the damping ratio is set to 0.05, and the first and third order vibration frequencies of the site are taken as The mass and stiffness proportional damping coefficient of the site model is calculated, where α and β are the mass and stiffness proportional damping coefficients, respectively; ξ is the damping ratio, which is taken as 0.05; ω1 and ω3 are the first and third order vibration frequencies, respectively.

[0012] In step 2, when selecting the initial geostress, in order to ensure the accuracy of the calculation results, the predefined field is used to apply the initial geostress to the site model, and the stress cloud map after the geostress is obtained is given by the preliminary selection test of blasting parameters; gravity is applied at the initial moment of calculation, that is, g = 9.81m / s 2 , Z axis is negative to achieve balance between internal and external forces.

[0013] In step 3, during the preliminary selection test of blasting parameters, simulation calculations are performed according to the calculation parameters in the JWL state equation parameter table of explosives and the basic parameter table of the surrounding rock constitutive model. The calculation results are consistent with the results of the preliminary selection test of blasting parameters. The blasting rock breaking effect diagrams at different times of the preliminary selection test of blasting parameters are obtained, and the kinetic energy evolution process of the entire model is analyzed.

[0014] In step 3, during the blasting parameter optimization test, simulation calculations are performed according to the calculation parameters of the explosive JWL state equation parameter table and the basic parameter table of the surrounding rock constitutive model to obtain the blasting and rock breaking effects at different times of the blasting parameter optimization test. The initial delay time is ignored and the kinetic energy evolution process of the entire model is analyzed.

[0015] In step 3, during the through-blasting test, simulation calculations are also performed according to the calculation parameters of the JWL state equation parameter table of explosives and the basic parameter table of the surrounding rock constitutive model. The calculation results are connected to obtain the blasting and rock breaking effect diagrams at different times of the through-blasting test, analyze the kinetic energy time course in the through-blasting test, and verify whether the delay time of the detonation network meets the requirements of blasting and forming of the single-faced rock plug.

[0016] The main beneficial effects of the present invention are:

[0017] According to the engineering background of rock plug blasting at the water intake and the special blasting test plan, a tunnel finite element model including drilling, plugging, explosive pack preparation, detonation point and delay time setting operations was established based on the ABAQUS / Explicit platform.

[0018] Based on the preliminary selection test of blasting parameters and the blasting parameter optimization test, the tensile failure threshold of the surrounding rock under natural conditions was inverted through repeated calculations. Based on this threshold, the rock breaking effect of the first rock plug blasting and the blasting parameter optimization test was reproduced, and the breakthrough effect of the breakthrough test was achieved. This proves that the simulation method used can reflect the reality more accurately, and the blasting design scheme can effectively achieve breakthrough, which provides a reference for the final formal rock plug blasting design optimization.

[0019] In the simulation of the preliminary selection test of blasting parameters, the penetration was 0.8m, and the punching effect was reflected. The moment when the kinetic energy of the model increased sharply corresponded to the detonation moments of the detonation network.

[0020] In the simulation of the blasting parameter optimization test, the penetration distance is about 4.5m. The moment when the model kinetic energy increases sharply corresponds to the detonation moment in the blasting design plan, and the kinetic energy value is smaller than that in the preliminary selection test of the blasting parameters.

[0021] The blasting process of the 8.3m long penetration test was simulated, and the calculation results showed that smooth blasting and forming could be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0023] Figure 1 It is a schematic diagram of the predefined field of the present invention.

[0024] Figure 2 This is a comparison diagram of the initial geostress fields in three different directions of the present invention.

[0025] Figure 3 This is a corresponding diagram of the blasting effects at different times in the preliminary selection test of blasting parameters of the present invention.

[0026] Figure 4 This is the kinetic energy evolution diagram of the preliminary selection test of blasting parameters of the present invention.

[0027] Figure 5This is a corresponding diagram of the blasting effects at different times in the blasting parameter optimization test of the present invention.

[0028] Figure 6 This is the kinetic energy evolution diagram of the blasting parameter optimization test of the present invention.

[0029] Figure 7 It is a corresponding diagram of the blasting effect at different times of the through blasting test of the present invention.

[0030] Figure 8 This is the kinetic energy evolution diagram of the through-blasting test of the present invention.

[0031] Fig. 9 This is the detonation network diagram of the blasting parameter optimization test of the present invention.

[0032] Fig.10 This is a layout diagram of blast holes for through blasting test of the present invention. DETAILED DESCRIPTION

[0033] like Figures 1 to 10 In the figure, a numerical simulation inversion analysis method for single-face rock plug blasting is shown, which includes the following steps:

[0034] Step 1: Establish an inversion analysis model, using the ABAQUS / Explicit platform to establish a blasting parameter preliminary selection test model, a blasting parameter optimization test model, and a through blasting test model;

[0035] Step 2, inversion analysis parameter selection, including calculation parameter selection and initial geostress selection;

[0036] Step 3: numerical simulation inversion analysis and calculation, including blasting parameter preliminary selection test, blasting parameter optimization test and through-blasting test.

[0037] In the preferred scheme, in step 2, the explosive material is described by the JWL state equation, and the basic physical parameters of the explosive are obtained by referring to the test results of blasting equipment, that is, the JWL state equation parameter table of explosives, and combined with the blasting parameter preliminary selection test and the blasting parameter optimization test, after repeated calculations, the material parameters that can fully reflect the results of the above two tests are finally obtained, that is, the basic parameter table of the surrounding rock constitutive model; according to the blasting test design, the detonation time of each hole and the coordinates of the detonation points at the hole mouth and the hole bottom are set.

[0038] Preferably, the reference values ​​of the basic physical parameters of the explosives are shown in the JWL state equation parameter table of explosives.

[0039] Explosive JWL state equation parameter table

[0040]

[0041] Preferably, the material parameter values ​​that can fully reflect the above two test results are finally obtained through repeated calculations and are shown in the basic parameter table of the surrounding rock constitutive model.

[0042] Basic parameters of surrounding rock constitutive model

[0043]

[0044] In the preferred solution, in step 2, when selecting the calculation parameters, Rayleigh damping is used, the damping ratio is set to 0.05, and the first and third order vibration frequencies of the site are taken as the basis The mass and stiffness proportional damping coefficient of the site model is calculated, where α and β are the mass and stiffness proportional damping coefficients, respectively; ξ is the damping ratio, which is taken as 0.05; ω1 and ω3 are the first and third order vibration frequencies, respectively.

[0045] Preferably, since the use of undamped geotechnical materials in dynamic problems may lead to distortion of calculation results, reasonable setting of material damping is a key link in the calculation of dynamic problems. Therefore, Rayleigh damping is used, the damping ratio is set to 0.05, and the first and third order vibration frequencies of the site are taken to calculate the mass and stiffness proportional damping coefficient of the site model according to the following formula:

[0046]

[0047] In the formula, α and β are mass and stiffness proportional damping coefficients respectively; ξ is the damping ratio, which is taken as 0.05; ω1 and ω3 are the first and third order vibration frequencies respectively. After calculation, α and β are 0.0420418 and 0.005618 respectively.

[0048] In the preferred solution, in step 2, when the initial geostress is selected, in order to ensure the accuracy of the calculation results, the predefined field is used to apply the initial geostress to the site model, and the stress cloud map after the geostress is obtained is given by the preliminary selection test of blasting parameters; the gravity is applied at the initial moment of calculation, that is, g = 9.81m / s 2 , Z axis is negative to achieve balance between internal and external forces.

[0049] Preferably, the initial gravitational field includes a horizontal direction -1, that is, the X-axis direction; a horizontal direction -2, that is, the Y-axis direction; and a vertical direction, that is, the Z-axis direction.

[0050] In the preferred scheme, in step 3, during the preliminary selection test of blasting parameters, simulation calculations are performed according to the calculation parameters in the JWL state equation parameter table of explosives and the basic parameter table of the surrounding rock constitutive model, and the calculation results are consistent with the results of the preliminary selection test of blasting parameters. The blasting rock breaking effect diagrams at different times of the preliminary selection test of blasting parameters are obtained, and the kinetic energy evolution process of the entire model is analyzed.

[0051] Preferably, the blasting rock breaking effect diagrams at different times of the blasting parameter preliminary selection test include effect diagrams 200ms after E hole detonation, 300ms after G circle detonation, 400ms after H circle detonation, 500ms after J circle detonation, and 600ms after K circle detonation.

[0052] Preferably, it can be seen from the blasting rock breaking effect diagram at different times of the preliminary test that after the E hole was detonated, only the face rock was blasted at the center. Although there was deformation in the hole, there was no obvious blasting pit, and only a small number of units were deleted; after the G circle was detonated, the blasting part of the face surface was significantly increased, and no unit deletion occurred in the holes of the G circle, which well simulated the punching phenomenon in the preliminary test of blasting parameters. At the same time, the phenomenon of the blocking part being blasted was particularly obvious. At this time, the footage depth at the center was about 0.8m, which was close to the actual 0.5m; after the H circle was detonated, the blasting part of the face surface was further increased, and there was still no blasting in the H circle hole; after the J circle was detonated, the face was blasted or broken in a large area, and the cracks had extended to the location of the contour hole; after the K circle was detonated, the face was completely blasted, and the footage on the entire face was relatively uniform, about 0.8m, which was consistent with the actual blasting results, verifying the reliability of the selected calculation parameters. Since the numerical simulation uses unit deletion technology, the blasting flying stone phenomenon cannot be presented.

[0053] In addition, the kinetic energy evolution process of the entire model is analyzed, ignoring the initial delay time. It can be seen that the kinetic energy of the entire system gradually increases with the blasting process, and there are multiple steep increases, and the steep increase moments correspond to the delay time of the detonation network. The calculation results of unit deletion and kinetic energy show that the simulation method used can accurately simulate the blasting and rock breaking process.

[0054] In the preferred scheme, in step 3, during the blasting parameter optimization test, simulation calculations are also performed according to the calculation parameters of the explosive JWL state equation parameter table and the basic parameter table of the surrounding rock constitutive model to obtain the blasting and rock breaking effects at different times of the blasting parameter optimization test, and then the initial delay time is ignored to analyze the kinetic energy evolution process of the entire model.

[0055] Preferably, the blasting parameter optimization test tests the rock breaking effects of blasting at different times, including effect diagrams at 400ms after the center hole detonation, 700ms after the G circle detonation, 900ms after the H circle detonation, 1000ms after the J circle detonation and 1100ms after the K circle detonation.

[0056] Preferably, in general, since the blasting parameter optimization test increased the amount of explosives, the footage in the blasting parameter optimization test increased significantly compared with the blasting parameter preliminary test, and the footage depth reached 4.5m, and there were obvious cracks at the bottom of the hole and the rock was more broken. After the two central holes were detonated, the groove was successfully excavated, an effective air-facing surface was formed, and there was an over-excavation of no more than 0.4m at the bottom of the hole. The deletion of units after the blast also showed that there were a large number of cracks around the blasting groove, and the cracks at the hole mouth and the bottom of the hole were particularly developed. After the G circle was detonated, the groove was expanded, part of the rock around the hole collapsed, and a small number of units at the bottom of the hole were deleted, which can be determined as cracks formed after the explosion. After the H circle was detonated, the groove on the face did not expand, but the internal groove was expanded, and the rock also collapsed. After the J circle was detonated, most of the rocks on the face were broken and collapsed, among which there were large pieces, and a small number of cracks still appeared at the bottom of the hole. The shaping effect of the contour hole was obvious after detonation. Based on the above phenomena, it can be considered that the center trenching was successful, the enlarged hole blasting was effective, and the contour hole blasting achieved the expected purpose.

[0057] Preferably, it can be seen from the blasting rock breaking effect diagram at different times of the blasting parameter optimization test that the moment of kinetic energy abrupt increase corresponds to the delay time of the detonation network. At the same time, compared with the blasting parameter preliminary selection test, the kinetic energy of the blasting parameter optimization test is significantly smaller, because the delay time between circles in the blasting parameter optimization test is significantly longer than that in the blasting parameter preliminary selection test, so the vibration effect caused by the blasting is significantly reduced; in addition, the penetration depth in the blasting parameter optimization test is significantly greater than that in the blasting parameter preliminary selection test, so more blasting energy is absorbed by the surrounding rock unit and converted into plastic strain energy, viscous dissipated energy, etc., and the part converted into kinetic energy is correspondingly reduced.

[0058] In the preferred scheme, in step 3, during the through-blasting test, simulation calculations are also performed according to the calculation parameters of the JWL state equation parameter table of the explosive and the basic parameter table of the surrounding rock constitutive model, and the calculation results are connected to obtain blasting and rock breaking effect diagrams at different times of the through-blasting test, analyze the kinetic energy time course in the through-blasting test, and verify whether the delay time of the detonation network meets the requirements of blasting and forming of the single-faced rock plug.

[0059] Preferably, the blasting and rock breaking effect diagrams at different times of the penetration test include effect diagrams 100ms after the center hole detonation, 500ms after the G circle detonation, 700ms after the H circle detonation, 800ms after the J circle detonation, 900ms after the K circle detonation and 1000ms after the L circle detonation.

[0060] Preferably, it can be seen from the blasting and rock breaking effect diagram at different times of the breakthrough test that the tunnel has been penetrated after the center hole is detonated. Due to the detonation at the head and tail points, the blasting and rock breaking effects at the hole mouth and the hole bottom are more obvious than those in the middle section; subsequently, as the G, H, J, and K circles are detonated in succession, the penetration area gradually increases; after the L circle is detonated, a smooth surface contour is formed, achieving the expected goal of complete breakthrough.

[0061] Preferably, it can be seen from the time history in the kinetic energy evolution diagram in the through-blasting test that the steep increase moment in the time history curve still corresponds to the delay time of the detonation network.

[0062] Preferably, the above numerical simulation inversion analysis method for single-face rock plug blasting is based on the ABAQUS / Explicit platform to establish a tunnel finite element model including operations such as drilling, plugging, charge preparation, detonation point and delay time setting. Based on the blasting parameter preliminary selection test and the blasting parameter optimization test, the tensile failure threshold of the surrounding rock under natural conditions is inverted after repeated trials, and the rock breaking effect of the first rock plug blasting and blasting parameter optimization test is reproduced based on this threshold, and the penetration effect of the penetration test is achieved, which proves that the simulation method used can more accurately reflect the actual situation, and the blasting design scheme can effectively achieve penetration, which provides a reference for the final formal rock plug blasting design optimization. The specific effects are as follows:

[0063] In the simulation of the preliminary selection test of blasting parameters, the penetration was 0.8m, and the punching effect was reflected. The moment when the kinetic energy of the model increased sharply corresponded to the detonation moments of the detonation network.

[0064] In the simulation of the blasting parameter optimization test, the penetration distance is about 4.5m. The moment when the model kinetic energy increases sharply corresponds to the detonation moment in the blasting design plan, and the kinetic energy value is smaller than that in the preliminary selection test of the blasting parameters.

[0065] The blasting process of an 8.3m long penetration test was simulated, and the calculation results showed that smooth blasting and forming were achieved.

[0066] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A numerical simulation inversion analysis method for single-face rock plug blasting, characterized in that: It includes the following steps: Step 1: Establish an inversion analysis model, using the ABAQUS / Explicit platform to establish a blasting parameter preliminary selection test model, a blasting parameter optimization test model, and a through blasting test model; Step 2, inversion analysis parameter selection, including calculation parameter selection and initial geostress selection; In step 2, the explosive material is expressed by the JWL state equation, and the basic physical parameters of the explosive are obtained by referring to the test results of blasting equipment, that is, the JWL state equation parameter table of explosives, and combined with the blasting parameter preliminary selection test and the blasting parameter optimization test, after repeated trials, the material parameters that can fully reflect the results of the blasting parameter preliminary selection test and the blasting parameter optimization test are finally obtained, that is, the basic parameter table of the surrounding rock constitutive model; according to the blasting test design, the detonation time of each hole and the coordinates of the detonation points of the hole mouth and the hole bottom are set; In step 2, when selecting the calculation parameters, Rayleigh damping is used, the damping ratio is set to 0.05, and the first and third order vibration frequencies of the site are taken as The mass and stiffness proportional damping coefficient of the site model is calculated, where: are the mass and stiffness proportional damping coefficients, respectively; is the damping ratio, which is taken as 0.05; are the first and third order vibration frequencies respectively; Step 3: numerical simulation inversion analysis and calculation, including blasting parameter preliminary selection test, blasting parameter optimization test and through-blasting test.

2. The numerical simulation inversion analysis method for single-face rock plug blasting according to claim 1 is characterized in that: In step 2, when selecting the initial geostress, in order to ensure the accuracy of the calculation results, the predefined field is used to apply the initial geostress to the site model, and the stress cloud map after the geostress is obtained is given by the preliminary selection test of blasting parameters; gravity is applied at the initial moment of calculation, that is, g=9.81m / s 2 , Z axis is negative to achieve balance between internal and external forces.

3. The numerical simulation inversion analysis method for single-face rock plug blasting according to claim 1 is characterized in that: In step 3, during the preliminary selection test of blasting parameters, simulation calculations are performed according to the calculation parameters in the JWL state equation parameter table of explosives and the basic parameter table of the surrounding rock constitutive model. The calculation results are consistent with the results of the preliminary selection test of blasting parameters. The blasting rock breaking effect diagrams at different times of the preliminary selection test of blasting parameters are obtained, and the kinetic energy evolution process of the entire model is analyzed.

4. The numerical simulation inversion analysis method for single-face rock plug blasting according to claim 1 is characterized in that: In step 3, during the blasting parameter optimization test, simulation calculations are also performed according to the calculation parameters of the JWL state equation parameter table of explosives and the basic parameter table of the surrounding rock constitutive model to obtain the blasting and rock breaking effects at different times of the blasting parameter optimization test. The initial delay time is then ignored to analyze the kinetic energy evolution process of the entire model.

5. The numerical simulation inversion analysis method for single-face rock plug blasting according to claim 1 is characterized in that: In step 3, during the through-blasting test, simulation calculations are also performed according to the calculation parameters of the JWL state equation parameter table of the explosive and the basic parameter table of the surrounding rock constitutive model. The calculation results are connected to obtain the blasting and rock breaking effect diagrams at different times of the through-blasting test, analyze the kinetic energy time course in the through-blasting test, and judge whether the delay time of the detonation network meets the requirements of blasting and forming of the single-faced rock plug.

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