Strip mine blasting numerical simulation analysis method based on RHT constitutive model

Abstract

The invention discloses a strip mine blasting numerical simulation analysis method based on an RHT constitutive model, and the method comprises the following steps: S1, building a strip mine blasting model: building a three-dimensional model through ANSYS software according to the actual geological conditions and blasting design requirements of a strip mine, and determining the geometric dimension of the model, the arrangement of blast holes, and the parameters of a charging structure; s2, determining material parameters: performing sampling and physical and mechanical property testing on field rocks of the strip mine to obtain rock parameters, determining rock material parameters in combination with an RHT constitutive model, determining explosive material parameters according to types of explosives used on site, and determining parameters of other related materials such as air and filling materials. According to the method, the RHT constitutive model is adopted, so that the accuracy of numerical simulation is improved; a more reliable basis is provided for blasting engineering design; the method has obvious economic benefits and social benefits; and powerful technical support is provided for the development of the strip mine blasting technology.

Description

Technical Field

[0001] The present invention relates to the technical field of open-pit mine blasting, and in particular to a numerical simulation analysis method for open-pit mine blasting based on a RHT constitutive model. Background Art

[0002] Open-pit blasting is a key link in mining, and its effectiveness directly affects the production efficiency, cost, and safety of the mine. In blasting engineering, it is crucial to accurately predict the blasting effect and control the impact of blasting vibration on the surrounding environment. Traditional blasting design mainly relies on experience and field tests, which is not only costly and time-consuming, but also difficult to fully consider the influence of complex geological conditions and blasting parameters. With the development of computer technology and numerical simulation methods, the use of numerical simulation software to study open-pit blasting has become an important means. However, in the process of simulating rock blasting, the existing numerical simulation methods are not accurate enough in the selection of rock constitutive models and parameter determination, resulting in deviations between the simulation results and the actual situation, and unable to provide reliable guidance for blasting engineering. Summary of the Invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a numerical simulation analysis method for open-pit mine blasting based on the RHT constitutive model.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A numerical simulation analysis method for open-pit mine blasting based on the RHT constitutive model includes the following steps: S1. Establish open-pit mine blasting model: Based on the actual geological conditions of the open-pit mine and the blasting design requirements, use ANSYS software to create a three-dimensional model and determine the model's geometric dimensions, blasthole arrangement, and charge structure parameters; S2. Determine material parameters: Sampling and testing the physical and mechanical properties of rocks at the open-pit mine site to obtain rock parameters. The rock material parameters are determined using the RHT constitutive model. The explosive material parameters are determined based on the type of explosives used on site. The parameters of other related materials, such as air and filling materials, are also determined. S3. Select the calculation algorithm and set the boundary conditions: Use the ALE algorithm for simulation calculation, apply non-reflective boundary conditions on the side and bottom surfaces of the model, and set a free boundary condition on the top; S4. Perform numerical simulation calculations: Set the solution control parameters in ANSYS / LS-DYNA software, submit the solver for calculation, and observe the blasting process of the model; S5. Analyze simulation results: Extract stress data at key locations in the model, plot stress time history curves, and analyze stress variation patterns; observe rock damage and analyze the scope and extent of damage; set vibration monitoring points to monitor the vibration velocity and frequency during blasting, plot vibration velocity time history curves, and analyze the impact on the surrounding environment and buildings; S6. Verify the simulation results: Compare and analyze the numerical simulation results with the on-site blasting test results. If the simulation results are consistent with the test results, the simulation method is feasible; if there is a deviation, adjust and optimize the model parameters and re-perform the simulation calculation until the simulation results are satisfactorily consistent with the test results.

[0005] Preferably, in step S1, the geometric dimensions of the model and the blasthole arrangement parameters are determined according to the actual situation of the open-pit mine, including blasthole diameter, step chassis resistance line, step height, blasthole depth, blasthole overdepth, blockage length, charging height, hole spacing, step slope angle, etc.

[0006] Preferably, in step S2, the rock material parameters include strain rate parameters, state equation parameters, damage parameters, and failure surface parameters, which are determined by testing the physical and mechanical properties of the rock and calculating using relevant formulas.

[0007] Preferably, in step S5, the degree and scope of damage to the rock caused by blasting are evaluated by stress analysis, the rock crushing effect is understood by damage analysis, and the impact on the surrounding environment and buildings is evaluated by blasting vibration analysis.

[0008] Preferably, in step S1, a mapping grid is used to divide the rock material portion, a sweeping grid is used to divide the air material and the explosive material, and the grid around the blast hole is encrypted to improve calculation accuracy.

[0009] Preferably, in step S2, the state equation of the explosive material adopts the Jones-Wilkins-Lee equation, and the parameters in the equation are determined by test data or empirical formulas.

[0010] Preferably, in step S5, the damaged area of ​​the rock is visualized using the post-processing function of the software to intuitively display the damage range and extent, and is evaluated using quantitative indicators, including damage area ratio and damage depth.

[0011] Preferably, in step S6, in addition to comparing the rock fragmentation size and blasting vibration velocity, the blast pile morphology and foundation condition parameters are also compared to comprehensively evaluate the consistency of the simulation results with the field blasting test results.

[0012] Preferably, in step S4, multiple groups of simulations are performed by adjusting the control parameters multiple times, and the stress, damage and vibration related data in different groups of simulation results are compared. The parameter combination that makes the simulation results most consistent with the actual engineering needs is selected as the final simulation parameter to optimize the simulation process.

[0013] Preferably, in step S5, the vibration velocity data obtained from the vibration monitoring point is processed using a spectrum analysis method to obtain the frequency distribution characteristics of the blasting vibration, and the impact of the blasting vibration on the rock crushing effect and the stability of the surrounding buildings is evaluated in combination with the natural frequencies of the rock and surrounding buildings.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, the RHT constitutive model is used to accurately describe the damage evolution process of rock under dynamic loads, more accurately characterize tensile damage, and improve the accuracy of numerical simulation.

[0015] 2. In the present invention, by accurately measuring and reasonably determining the rock material parameters and optimizing the calculation algorithm and boundary conditions, the simulation results are closer to the actual blasting situation, providing a more reliable basis for blasting engineering design.

[0016] 3. In the present invention, numerical simulation and field tests are combined to conduct multi-faceted analysis and verification of the blasting effect, which can not only optimize the blasting parameters and improve the blasting quality, but also reduce the impact of blasting vibration on the surrounding environment, with significant economic and social benefits.

[0017] 4. In the present invention, the simulation analysis method is universal and can be applied to simulation studies of different geological conditions and blasting projects, providing strong technical support for the development of open-pit mine blasting technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a logic block diagram of a numerical simulation analysis method for open-pit mine blasting based on the RHT constitutive model proposed in this invention. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] Reference Figure 1 , a numerical simulation analysis method for open-pit mine blasting based on the RHT constitutive model, comprising the following steps: S1. Establish open-pit mine blasting model: Based on the actual geological conditions of the open-pit mine and the blasting design requirements, use ANSYS software to create a three-dimensional model and determine the model's geometric dimensions, blasthole arrangement, and charge structure parameters; S2. Determine material parameters: Sampling and testing the physical and mechanical properties of rocks at the open-pit mine site to obtain rock parameters. The rock material parameters are determined using the RHT constitutive model. The explosive material parameters are determined based on the type of explosives used on site. The parameters of other related materials, such as air and filling materials, are also determined. S3. Select the calculation algorithm and set the boundary conditions: Use the ALE algorithm for simulation calculation, apply non-reflective boundary conditions on the side and bottom surfaces of the model, and set a free boundary condition on the top; S4. Perform numerical simulation calculations: Set the solution control parameters in ANSYS / LS-DYNA software, submit the solver for calculation, and observe the blasting process of the model; S5. Analyze simulation results: Extract stress data at key locations in the model, plot stress time history curves, and analyze stress variation patterns; observe rock damage and analyze the scope and extent of damage; set vibration monitoring points to monitor the vibration velocity and frequency during blasting, plot vibration velocity time history curves, and analyze the impact on the surrounding environment and buildings; S6. Verify the simulation results: Compare and analyze the numerical simulation results with the on-site blasting test results. If the simulation results are consistent with the test results, the simulation method is feasible; if there is a deviation, adjust and optimize the model parameters and re-perform the simulation calculation until the simulation results are satisfactorily consistent with the test results.

[0021] In step S1, the geometric dimensions of the model and the blasthole arrangement parameters are determined according to the actual situation of the open-pit mine, including the blasthole diameter, step chassis resistance line, step height, blasthole depth, blasthole overdepth, blockage length, charge height, hole spacing, step slope angle, etc.

[0022] In step S2, the rock material parameters include strain rate parameters, state equation parameters, damage parameters, and failure surface parameters, which are determined by testing the physical and mechanical properties of the rock and calculating using relevant formulas.

[0023] In step S5, the degree and scope of rock damage caused by blasting are evaluated through stress analysis, the rock crushing effect is understood through damage analysis, and the impact on the surrounding environment and buildings is evaluated through blasting vibration analysis.

[0024] In step S1, a mapping grid is used to divide the rock material portion, a sweeping grid is used to divide the air material and the explosive material, and the grid around the blasthole is encrypted to improve the calculation accuracy.

[0025] In step S2, the state equation of the explosive material adopts the Jones-Wilkins-Lee equation, and the parameters in the equation are determined through test data or empirical formulas.

[0026] In step S5, the post-processing function of the software is used to visualize the damaged area of ​​the rock, intuitively display the damage range and extent, and evaluate it through quantitative indicators, including damage area ratio and damage depth.

[0027] In step S6, in addition to comparing the rock fragmentation size and blasting vibration velocity, the blast pile morphology and foundation condition parameters are also compared to comprehensively evaluate the consistency of the simulation results with the field blasting test results.

[0028] In step S4, multiple simulations are performed by adjusting the control parameters multiple times, and the stress, damage, and vibration-related data in the simulation results of different groups are compared. The parameter combination that makes the simulation results most consistent with the actual engineering needs is selected as the final simulation parameter to optimize the simulation process.

[0029] In step S5, the vibration velocity data obtained from the vibration monitoring points are processed using a spectrum analysis method to obtain the frequency distribution characteristics of the blasting vibration. Combined with the natural frequencies of the rock and surrounding buildings, the impact of the blasting vibration on the rock crushing effect and the stability of the surrounding buildings is evaluated. Example

[0030] For example, in an open-pit mine, the bench height is 12m, the blasthole diameter is 150mm, the hole spacing is 6.0m, the row spacing is 5.0m, the blasthole overdepth is 1.5m, the charge height is 9.5m, and the plug length is 4m. The rock is primarily migmatite; its physical and mechanical parameters are as follows: density 2.65g / cm³, wave velocity 3826m / s, compressive strength 76.5MPa, tensile strength 6.03MPa, internal friction angle 37.48°, elastic modulus 45.17GPa, and Poisson's ratio 0.28. S1. Establish open-pit mine blasting model: ANSYS software was used to create a three-dimensional model. The length, width, and height of the model, as well as the position and parameters of the blastholes, were set according to the actual project dimensions. The model was then meshed. Mapped meshing was used for the rock material portion, and the mesh size around the blastholes was 20 cm to ensure calculation accuracy. Sweep meshing was used for the air and explosive materials, with an air cell size of 20 cm and an explosive cell size of 10 cm.

[0031] S2. Determine material parameters: Rock material parameters: The parameters of the RHT constitutive model were determined based on the physical and mechanical parameters of the migmatite. The strain rate parameters are βc = 0.016, βt = 0.021; the P-α equation of state parameters are A1 = 38.8 GPa, A2 = 47.3 GPa, A3 = 9.9 GPa, and B0 = B1 = 1.22; the damage parameters are D1 = 0.04, D2 = 1.0; and the failure surface parameters are A = 2.53 and N = 0.71.

[0032] Explosive material parameters: Emulsion explosives were used as the experimental explosives. The *MAT_HIGH_EXPLOSIVE_BURN model was selected in the software. The equation of state was defined by Jones-Wilkins-Lee (JWL) with the following parameters: density of 1.22 g / cm3, detonation velocity of 0.5122 cm / μs, A=2.762 MPa, B=0.0844 MPa, R1=5.2, R2=2.1, ω=0.5, and E=0.0387 MPa.

[0033] Air material parameters: The air material model uses MAT_NULL, the density takes the standard density of 1.29×10−3 g / cm3, the state equation is defined by EOS_LINEAR_POLYOMIAL, and the corresponding constant parameters are set.

[0034] S3. Select calculation algorithm and set boundary conditions: The ALE algorithm was selected for simulation calculations, and non-reflecting boundary conditions were applied to the side and bottom surfaces of the model, and free boundary conditions were set on the top.

[0035] S4. Perform numerical simulation calculations: The solution control parameters are set in ANSYS / LS-DYNA software, and numerical simulation calculations are performed to simulate the blasting process under different delayed detonation times.

[0036] S5. Analyze simulation results: Stress Analysis: Five stress monitoring points were set up in the model, located at the borehole mouths and on the perpendicular bisector of the borehole line. Stress data for each monitoring point was extracted for different delay initiation times, and stress time history curves were plotted. The results show that as the delay initiation time between holes increases from 16ms to 31ms, the average maximum effective stress at each monitoring point decreases, then increases, and then decreases again. At a delay of 25ms, the average maximum effective stress reaches its peak, promoting better blasting and fragmentation of the rock.

[0037] Damage analysis: The rock damage was observed through the software post-processing function. It was found that the damage of the charging structure with an upper water medium interval of 1m and a lower water medium interval of 1m was evenly distributed along the blasthole and the range was regular, which can significantly improve the blasting effect and reduce the foundation.

[0038] Blasting Vibration Analysis: Five vibration monitoring points were set up to monitor vibration velocity during the blasting process. Vibration velocity time history curves were plotted to analyze the effects of different delay initiation times on blasting vibration. The results showed that the average maximum vibration velocity at each monitoring point gradually decreased with increasing delay initiation time. Taking into account the actual conditions at the test stope, a 25ms delay between holes was determined to be the optimal delay for simulation calculations.

[0039] S6. Verify simulation results: Field blasting tests were conducted at the open-pit mine, using a 25ms inter-hole delay and a 65ms inter-row delay. The rock fragmentation of the blast pile was measured, and images of the top and front surfaces of the blast pile were acquired, processed, and analyzed using split-desktop software. The results showed that the rock fragmentation on the top surface was predominantly smaller than 5 cm, accounting for 57.08%, with the largest fragment size being 24.36 cm. The rock fragmentation on the front surface of the blast pile was predominantly smaller than 10 cm, accounting for 39.41%, and between 10 and 20 cm, accounting for 33.97%. Fragments larger than 50 cm accounted for a very small proportion, with the largest fragment size being 70.05 cm. The overall blasting performance was good, consistent with the numerical simulation results, validating the accuracy and reliability of the simulation method.

[0040] In summary, we can see that the present invention adopts the RHT constitutive model, which can accurately describe the damage evolution process of rock under dynamic loads, more accurately characterize tensile damage, and improve the accuracy of numerical simulation; through the precise measurement and reasonable determination of rock material parameters, and the optimization selection of calculation algorithms and boundary conditions, the simulation results are closer to the actual blasting situation, providing a more reliable basis for blasting engineering design; combining numerical simulation and field tests, the blasting effect is analyzed and verified in many aspects, which can not only optimize the blasting parameters and improve the blasting quality, but also reduce the impact of blasting vibration on the surrounding environment, with significant economic and social benefits; and the simulation analysis method of the present invention is universal and can be applied to simulation studies of different geological conditions and blasting projects, providing strong technical support for the development of open-pit mine blasting technology.

[0041] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A numerical simulation analysis method for open-pit mine blasting based on the RHT constitutive model, characterized in that: The following steps are involved: S1. Establish open-pit mine blasting model: Based on the actual geological conditions of the open-pit mine and the blasting design requirements, use ANSYS software to create a three-dimensional model and determine the model's geometric dimensions, blasthole arrangement, and charge structure parameters; S2. Determine material parameters: Sampling and testing the physical and mechanical properties of rocks at the open-pit mine site to obtain rock parameters. The rock material parameters are determined using the RHT constitutive model. The explosive material parameters are determined based on the type of explosives used on site. The parameters of other related materials, such as air and filling materials, are also determined. S3. Select the calculation algorithm and set the boundary conditions: Use the ALE algorithm for simulation calculation, apply non-reflective boundary conditions on the side and bottom surfaces of the model, and set a free boundary condition on the top; S4. Perform numerical simulation calculations: Set the solution control parameters in ANSYS / LS-DYNA software, submit the solver for calculation, and observe the blasting process of the model; S5. Analyze simulation results: Extract stress data at key locations in the model, plot stress time history curves, and analyze stress variation patterns; observe rock damage and analyze the scope and extent of damage; set vibration monitoring points to monitor the vibration velocity and frequency during blasting, plot vibration velocity time history curves, and analyze the impact on the surrounding environment and buildings; S6. Verify the simulation results: Compare and analyze the numerical simulation results with the on-site blasting test results. If the simulation results are consistent with the test results, the simulation method is feasible; if there is a deviation, adjust and optimize the model parameters and re-perform the simulation calculation until the simulation results are satisfactorily consistent with the test results.

2. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S1, the geometric dimensions of the model and the blasthole arrangement parameters are determined according to the actual situation of the open-pit mine, including blasthole diameter, step chassis resistance line, step height, blasthole depth, blasthole overdepth, blockage length, charge height, hole spacing, step slope angle, etc.

3. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S2, the rock material parameters include strain rate parameters, state equation parameters, damage parameters, and failure surface parameters, which are determined by testing the physical and mechanical properties of the rock and calculating using relevant formulas.

4. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S5, the degree and scope of rock damage caused by blasting are evaluated through stress analysis, the rock crushing effect is understood through damage analysis, and the impact on the surrounding environment and buildings is evaluated through blasting vibration analysis.

5. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S1, a mapping grid is used to divide the rock material portion, a sweeping grid is used to divide the air material and the explosive material, and the grid around the blast hole is encrypted to improve the calculation accuracy.

6. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S2, the state equation of the explosive material adopts the Jones-Wilkins-Lee equation, and the parameters in the equation are determined through test data or empirical formulas.

7. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S5, the damaged area of ​​the rock is visualized using the post-processing function of the software to intuitively display the damage range and extent, and is evaluated using quantitative indicators, including damage area ratio and damage depth.

8. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S6, in addition to comparing the rock fragmentation size and blasting vibration velocity, the blast pile morphology and foundation condition parameters are also compared to comprehensively evaluate the consistency between the simulation results and the on-site blasting test results.

9. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S4, multiple groups of simulations are performed by adjusting the control parameters multiple times, and the stress, damage and vibration related data in the simulation results of different groups are compared. The parameter combination that makes the simulation results most consistent with the actual engineering needs is selected as the final simulation parameters to optimize the simulation process.

10. The method for numerical simulation analysis of open-pit mine blasting based on the RHT constitutive model according to claim 1, characterized in that: In step S5, the vibration velocity data obtained from the vibration monitoring points are processed using a spectrum analysis method to obtain the frequency distribution characteristics of the blasting vibration. Combined with the natural frequencies of the rock and surrounding buildings, the impact of the blasting vibration on the rock crushing effect and the stability of the surrounding buildings is evaluated.

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