Blasting parameter screening method and system in one-time well completion blasting of blind raise

Abstract

The invention belongs to the technical field of underground blasting, and discloses a blasting parameter screening method and system in one-time well completion blasting of a blind raise. The method comprises the steps that a slotting mode is determined, and then the slotting mode, the number of empty holes, the hole distance between the empty holes and charging holes and the filling length parameters are determined; explosive load calculation, wherein reasonable explosive loads and non-coupling coefficients of the slotting holes and the peripheral holes are determined according to numerical simulation calculation and blasting funnel test results; delay time is determined, the optimal influence time of inter-hole delay on the explosion stress wave superposition effect is calculated in a numerical simulation mode, and the damage effect of stress waves on rocks is optimal; and filling and charging are conducted, due to the fact that upward non-coupling charging is adopted, a reasonable charging mode is determined to ensure the accuracy of the charging amount and the explosive position, and reasonable filling is set to ensure that the explosive energy fully acts on the exploded rock mass. The safety of well completion operation can be greatly improved; the maximum utilization of resources is realized, and the economic benefit is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of underground blasting, and in particular relates to a method and system for screening blasting parameters in a blind well primary well completion blasting. Background Art

[0002] Regarding underground blasting technology, domestic and foreign scholars have formed a scientific and complete system. They have conducted in-depth research from rock property testing to the design of different blasting parameters and have achieved certain research results. In terms of rock mechanics parameter calibration, Peng Jianyu conducted relevant experimental and numerical simulation studies on the formation of blasting funnels of rocks under static stress, the fracture behavior of sandstone under the impact load of Hopkinson bar under static stress, and the blasting and crushing behavior of cement mortar samples under static stress. He studied the phenomena and laws in the dynamic fracture process of rocks under static stress and revealed the destruction mechanism of rocks under dynamic and static loads. In terms of blasting funnels, Wang Peng and others used ANSYS / LS-DYNA nonlinear three-dimensional dynamic finite element software to numerically simulate the stress distribution and propagation mechanism of rocks under multi-hole same-segment blasting. The stress distribution cloud maps at different times and the stress-time history curves of typical units were obtained. According to the results, the stress wave propagation law and the formation process of blasting funnels were studied, and the relevant factors affecting the formation of blasting funnels were discussed. In terms of rock explosiveness classification, Xue Jianguang and others established an attribute identification model for distinguishing rock explosiveness classification in engineering blasting; they selected rock density, tensile strength, impact dynamic load strength and rock integrity coefficient as identification indicators for attribute identification, effectively solving the problem of judging the difficulty of rock explosiveness.

[0003] In the research on key technologies for one-time blasting of upward blind shafts, the key to the one-time well completion technology of upward fan-shaped cutting shafts lies in the arrangement of the middle slot holes and the surrounding polished holes, selecting a reasonable center slot hole diameter and hole layout method to ensure the slot quality, and calculating blasting parameters such as the peripheral hole uncoupling coefficient, hole spacing and delay time to ensure that the cutting well size and quality meet the subsequent construction requirements.

[0004] Through the above analysis, the problems and defects of the existing technology are as follows: in the existing technology of one-time well completion technology for fan-shaped cutting wells, the control effect on relevant parameters such as the number of well expansion holes, delay time, and charge amount is poor, and it cannot ensure that the well completion size and the stability of the surrounding retained rock mass meet the design requirements. Summary of the invention

[0005] In order to overcome the problems existing in the related art, the disclosed embodiments of the present invention provide a method and system for screening blasting parameters in a blind shaft primary well completion blasting.

[0006] The technical solution is as follows: A method for screening blasting parameters in a blind well primary well blasting, comprising the steps of:

[0007] S1, determine the slotting method, select the slotting scheme suitable for lithium ore rock according to the mining operation equipment and numerical simulation calculation and analysis results, and conduct field tests to determine the parameters of slotting form, number of empty holes, distance between empty holes and charging holes, and filling length;

[0008] S2, calculate the charge amount, determine the charge amount and uncoupling coefficient of the slot hole and surrounding holes through numerical simulation calculation and blasting funnel test results;

[0009] S3, determine the delay time, use numerical simulation to calculate the influence time of the inter-hole delay on the superposition of the explosion stress wave, and realize the destruction of the rock by the stress wave;

[0010] S4, filling and charging, determine the charging method to ensure the accuracy of the charging amount and the position of the explosives, and set up reasonable filling to ensure that the explosive energy fully acts on the blasted rock mass.

[0011] In step S2, the decoupling coefficient is the ratio of the borehole diameter to the charge diameter; the decoupling coefficient is 1.5 to 3.0; the peripheral hole spacing is 10 to 20 times the borehole diameter; the borehole density coefficient of the peripheral holes is 0.8 to 1.0; the charge concentration of the peripheral holes is 70 to 120 kg / m in soft rock, 100 to 150 kg / m in medium hard rock, and 150 to 250 kg / m in hard rock.

[0012] Further, the method for determining the uncoupling coefficient includes:

[0013] According to the preliminarily determined ratio of the uncoupled blasthole diameter to the charge diameter, the uncoupling coefficient of the rock mass is preset. After the uncoupled charge type explosive material model is determined, the established JWL state equation of explosion and the LINEAR-POLYNOMIAL state equation of air fluid are used to calculate whether the tangential tensile stress generated by the uncoupled charge type explosive material model with different uncoupling coefficients is greater than the tensile strength of the rock. The ratio of the uncoupled blasthole diameter to the charge diameter of the rock mass and the uncoupling coefficient that meet the energy and resolution are determined as the optimized uncoupled charge type explosive material model to generate directional fracture parameters.

[0014] Furthermore, for the uncoupled charge explosive material model with different uncoupled coefficients, whether the tangential tensile stress generated by the excitation is greater than the tensile strength of the rock is calculated, including:

[0015] (1) During the explosion process, the explosive material model is simplified to an incompressible Newtonian explosion fluid, and the differential equation of motion of the explosion fluid is obtained based on Newton's second law. The continuity equation is derived from the mass conservation equation in the volume element, and the formula for the instantaneous tangential tensile stress generated by the explosion fluid is obtained. The tangential tensile stress distribution of the fluid in the calculated slot hole should be coupled with the flow field and pressure field.

[0016] (2) After the explosive material model explodes, the tangential tensile stress generated during the conversion into air fluid is determined by the tangential tensile stress pressure conduction equation;

[0017] (3) During the generation of explosive cracks, the rock mass is simplified into a rigid deformation model. Before the rock mass reaches the fracture strength, the tangential tensile stress-strain generated by the explosive material model is linearly related. After the stress reaches the fracture strength of the rock mass, it remains constant. The final strain is the sum of the fracture strain and the crack strain.

[0018] In step (1), the differential equation of motion of the explosion fluid is obtained according to Newton's second law, and the expression is:

[0019]

[0020] Where ρ' is the density of the explosion fluid, o, c, f are the pressure velocity components of the explosion fluid in the x, y, z axes respectively, e is the explosion movement time of the explosion fluid, h is the unit volume pressure of the explosion fluid, kx, ky, kz are the explosion pressure acceleration components in the three coordinate axis directions respectively, δ is the density of the explosion fluid after the explosion movement, is the Laplace operator.

[0021] In step (1), the continuity equation derived from the mass conservation equation in the volume element is used to obtain the formula for the instantaneous tangential tensile stress generated by the explosion fluid, which is expressed as follows:

[0022]

[0023] Where, I is the dispersion of the explosion fluid;

[0024] The tangential tensile stress distribution of the fluid in the computational slot hole should be coupled with the flow field and the pressure field, and the energy equation is as follows:

[0025]

[0026] In the formula, is the slope of the tangential tensile stress-pressure curve of the explosive material model, A is the tangential tensile stress, and J is the pressure conductivity of the explosive material model.

[0027] In step (2), after the explosive material model explodes, the tangential tensile stress generated during the conversion into air fluid is determined by the tangential tensile stress pressure conduction equation, which is expressed as:

[0028]

[0029] Where r is the internal energy of the explosive material model.

[0030] In step (3), the final strain is the sum of the fracture strain and the crack strain, expressed as:

[0031]

[0032] In the formula, is the theoretical stress of rock mass, E is the modulus of rupture, is the theoretical strain of rock mass, η s is the stress when cracks occur in the rock mass, is the strength of the rock mass at fracture, They are the corresponding strain when the rock mass breaks and the subsequent crack strain.

[0033] In step S3, the extension time is determined, including the steps of:

[0034] S301, through the three-dimensional lithium ore rock structure map, determine the blast hole axial height difference D and the straight line distance l between the blast hole explosion center in the blasting area of ​​the ore rock pre-blasting area; measure the shear wave velocity u of the blasting vibration wave in the rock mass h and the longitudinal wave velocity u z ; Determine the structural influence coefficient G through blasting vibration monitoring 2 and the influence coefficient of the blasthole axial height χ;

[0035] The vibration damping ratio in the same precise time-delay controlled blasting is the same. The blasting vibration velocity is affected by the axial height condition of the blasthole. The blasting vibration velocity is expressed as:

[0036] U (s) = sinθ×G 2 (D / l) χ

[0037] Where U (s) is the blasting vibration velocity, θ is the angle formed by the axial height difference D of the blasthole and the straight-line distance l;

[0038] S302, according to the calculation formula of blasting vibration velocity, the vibration frequency of the center of mass of the lithium ore rock mass body conforms to the dimensional analysis theorem and the π theorem. According to the straight-line distance between the ore rock pre-blasting area and the blast hole blast center and the axial height difference of the blast hole, the vibration frequency q of the center of mass of the lithium ore rock mass body is calculated as:

[0039] q=F·G 2 (D / l) χ

[0040] Where F is the frequency coefficient;

[0041] S303, by setting the delay time between holes, the adjacent vibration waveforms are N / 4 cycles apart when they arrive at the designated blasthole node, where N is an integer, so that the peaks of the two waveforms meet when the waveforms arrive at the position, thereby superimposing the amplitudes. The delay time between holes is calculated as follows:

[0042] According to the calculation formula of the centroid vibration frequency of lithium ore rock mass, the distance between the ore rock pre-blasting area and the blast hole is l 1 ,l 2 …l n ,l 1 <l 2 <… <l n , the axial height difference of the blast hole is D 1 ,D 2 …D n , the blast hole detonation time is s 1 ,s 2 …s n ,s 1 2 <… n ; At the same time, the distance difference between the blasthole and the pre-blasting area of ​​the ore rock is Δl = l n -l n-1 , the interval time between holes is Δs=s n -s n-1 ; The expression is:

[0043]

[0044] In the formula, l n is the distance between the ore pre-blasting area and the nth blast hole, l n-1 is the distance between the ore rock pre-blasting area and the n-1th blast hole, s n is the detonation time of the nth blast hole, s n-1 is the detonation time of the n-1th blast hole.

[0045] Another object of the present invention is to provide a blasting parameter screening system in a blind well primary well blasting, the system implements the blasting parameter screening method in a blind well primary well blasting, the system comprising:

[0046] The slotting method determination module is used to select the slotting scheme suitable for lithium ore and conduct field tests according to the mining operation equipment and numerical simulation calculation and analysis results, and determine the parameters of slotting form, number of empty holes, distance between empty holes and charging holes, and filling length;

[0047] The module for determining the uncoupling coefficient is used to determine the charge amount and uncoupling coefficient of the slot hole and the surrounding holes through numerical simulation calculations and blasting funnel test results;

[0048] The hole-to-hole delay determination module is used to calculate the influence time of the hole-to-hole delay on the superposition of the explosion stress wave by numerical simulation, so as to achieve the destruction of the rock by the stress wave;

[0049] ​​The filling and charging module is used to determine the charging method to ensure the accuracy of the charging amount and the position of the explosives, and to set reasonable filling to ensure that the explosive energy fully acts on the blasted rock mass.

[0050] Combined with all the above technical solutions, the beneficial effects of the present invention are as follows: the blind shaft one-time well completion blasting parameter design of the present invention can realize the one-time well completion technology of the upward blind shaft, which can greatly improve the safety of well completion operations; maximize resource utilization and improve economic benefits. The present invention performs relevant calculations on the size and number of hollow holes in the one-time well completion blasting technology of the upward blind shaft to ensure that there is enough compensation space during blasting. Strict control of relevant parameters such as the number of well expansion holes, delay time, and charge amount ensures that the well completion size and the stability of the surrounding retained rock mass meet the design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the description, serve to explain the principles of the present disclosure;

[0052] Figure 1 It is a flow chart of a method for screening blasting parameters in a blind well primary well completion blasting provided by an embodiment of the present invention;

[0053] Figure 2 It is a schematic diagram of a blasting parameter screening system in a blind well primary well completion blasting provided by an embodiment of the present invention;

[0054] In the figure: 1. Module for determining the grooving method; 2. Module for determining the uncoupling coefficient; 3. Module for determining the delay between holes; 4. Module for filling and charging. DETAILED DESCRIPTION

[0055] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0056] Embodiment 1, as Figure 1 As shown, the method for screening blasting parameters in a blind well primary blasting provided by the embodiment of the present invention includes:

[0057] S1, determine the slotting method, select the slotting scheme suitable for lithium ore rock according to the mining operation equipment and numerical simulation calculation and analysis results, and conduct field tests to determine the parameters of slotting form, number of empty holes, distance between empty holes and charging holes, and filling length;

[0058] S2, calculate the charge amount, determine the charge amount and uncoupling coefficient of the slot hole and surrounding holes through numerical simulation calculation and blasting funnel test results;

[0059] S3, determine the delay time, use numerical simulation to calculate the influence time of the inter-hole delay on the superposition of the explosion stress wave, and realize the destruction of the rock by the stress wave;

[0060] S4, filling and charging, determine the charging method to ensure the accuracy of the charging amount and the position of the explosives, and set up reasonable filling to ensure that the explosive energy fully acts on the blasted rock mass.

[0061] Exemplarily, in step S2, the uncoupling coefficient in the blasting parameters refers to the ratio of the borehole diameter to the charge diameter. In controlled blasting, the uncoupling coefficient is a very important parameter, which is mainly used for pre-splitting blasting and smooth blasting. Its purpose is to protect the integrity of the blasting, to prevent cracking and reduce cracks, and to maintain the stability of the rock mass. The value of the uncoupling coefficient is generally between 1.5 and 3.0. At this time, the impact pressure (or stress generated) on the rock of the borehole wall can be no greater than the ultimate compressive strength of the rock, avoiding the formation of a crushing circle, thereby leaving a half-borehole mark. At the same time, the tangential tensile stress generated on the borehole centerline is greater than the tensile strength of the rock, resulting in directional cracks.

[0062] In smooth blasting, when the non-coupling coefficient of the peripheral holes is 2 to 5, the smooth blasting effect is the best; the peripheral hole spacing is generally 10 to 20 times the diameter of the blast hole; the blast hole density coefficient of the peripheral holes is generally 0.8 to 1.0; the charge concentration of the peripheral holes is generally 70 to 120 kg / m in soft rock, 100 to 150 kg / m in medium-hard rock, and 150 to 250 kg / m in hard rock;

[0063] Exemplarily, the method for determining the uncoupling coefficient includes:

[0064] According to the ratio of the uncoupled blasthole diameter to the charge diameter determined initially, a series of corresponding uncoupling coefficients are preset for the rock mass. After the uncoupled charge type explosive material model is determined, the established JWL state equation of explosion action and the LINEAR-POLYNOMIAL state equation of air fluid are used to calculate whether the tangential tensile stress generated by the uncoupled charge type explosive material model with different uncoupling coefficients is greater than the tensile strength of the rock. The ratio of the uncoupled blasthole diameter to the charge diameter and the uncoupling coefficient that meet the energy and resolution are determined as the optimized uncoupled charge type explosive material model to generate directional fracture parameters.

[0065] Exemplarily, using the established JWL state equation of explosion and the LINEAR-POLYNOMIAL state equation of air fluid to calculate whether the tangential tensile stress generated by the uncoupled charge type explosive material model with different uncoupled coefficients is greater than the tensile strength of the rock includes:

[0066] (1) During the explosion process, the explosive material model is simplified to an incompressible Newtonian explosion fluid, and the motion differential equation of the explosion fluid is obtained according to Newton's second law:

[0067]

[0068] Where p' is the density of the explosion fluid, o, c, f are the pressure velocity components of the explosion fluid in the x, y, z axes respectively, e is the explosion time of the explosion fluid, h is the unit volume pressure of the explosion fluid, kx, ky, kz are the explosion pressure acceleration components in the three coordinate axis directions respectively, δ is the density of the explosion fluid after the explosion, is the Laplace operator.

[0069] According to the continuity equation derived from the mass conservation equation in the volume element, the formula for the instantaneous tangential tensile stress pressure generated by the explosion fluid is obtained:

[0070]

[0071] Where, I is the dispersion of the explosion fluid;

[0072] The tangential tensile stress distribution of the fluid in the computational slot hole should be coupled with the flow field and the pressure field, and the energy equation is as follows:

[0073]

[0074] In the formula, is the slope of the tangential tensile stress-pressure curve of the explosive material model, A is the tangential tensile stress, and J is the pressure conductivity of the explosive material model.

[0075] In step (2), after the explosive material model explodes, the tangential tensile stress generated during the conversion into air fluid is determined by the tangential tensile stress pressure conduction equation, which is expressed as:

[0076]

[0077] Where r is the internal energy of the explosive material model.

[0078] In step (3), the final strain is the sum of the fracture strain and the crack strain, expressed as:

[0079]

[0080] In the formula, is the theoretical stress of rock mass, E is the modulus of rupture, is the theoretical strain of rock mass, η s is the stress when cracks occur in the rock mass, is the strength of the rock mass at fracture, They are the corresponding strain when the rock mass breaks and the subsequent crack strain.

[0081] Exemplarily, in step S3, the extension time determination includes:

[0082] S301, through the three-dimensional lithium ore rock structure map, determine the blast hole axial height difference D and the straight line distance l between the blast hole explosion center in the blasting area of ​​the ore rock pre-blasting area; measure the shear wave velocity u of the blasting vibration wave in the rock mass h and the longitudinal wave velocity u z ; Determine the structural influence coefficient G through blasting vibration monitoring 2 and the influence coefficient of the blasthole axial height χ;

[0083] Assuming that the vibration damping ratio in the same precise time-delay controlled blasting is the same, the blasting vibration velocity is affected by the axial height condition of the blasthole, and the blasting vibration velocity is expressed as:

[0084] U (s) = sinθ×G 2 (D / l) χ

[0085] Where U (s) is the blasting vibration velocity, θ is the angle formed by the axial height difference D of the blasthole and the straight-line distance l;

[0086] S302, according to the calculation formula of blasting vibration velocity, the vibration frequency of the center of mass of the lithium ore rock mass body conforms to the dimensional analysis theorem and the π theorem. According to the straight-line distance between the ore rock pre-blasting area and the blast hole blast center and the axial height difference of the blast hole, the vibration frequency q of the center of mass of the lithium ore rock mass body is calculated as:

[0087] q=F·G 2 (D / l) χ

[0088] Where F is the frequency coefficient;

[0089] S303, by setting the delay time between holes, the adjacent vibration waveforms are N / 4 cycles apart when they arrive at the designated blasthole node, where N is an integer, so that the peaks of the two waveforms meet when the waveforms arrive at the position, thereby superimposing the amplitudes. The delay time between holes is calculated as follows:

[0090] According to the calculation formula of the centroid vibration frequency of lithium ore rock mass, the distance between the ore rock pre-blasting area and the blast hole is l 1 ,l 2 …l n ,l1 <l 2 <… <l n , the axial height difference of the blast hole is D 1 ,D 2 …D n , the blast hole detonation time is s 1 ,s 2 …s n ,s 1 2 <… n ; At the same time, the distance difference between the blasthole and the pre-blasting area of ​​the ore rock is Δl = l n -l n-1 , the interval time between holes is Δs=s n -s n-1 ; The expression is:

[0091]

[0092] In the formula, l n is the distance between the ore pre-blasting area and the nth blast hole, l n-1 is the distance between the ore rock pre-blasting area and the n-1th blast hole, s n is the detonation time of the nth blast hole, s n-1 is the detonation time of the n-1th blast hole.

[0093] Coupled charge: In this structure, the explosive does not completely explode the blast hole, but there is a certain gap between it and the hole wall. Air-spaced charge is a typical uncoupled charge, which uses air as a spacing medium to increase the height of the charge column, reduce the amount of charge, prolong the action time of the explosive gas in the blast hole, increase the action area of ​​the explosive gas, and reduce the damage of the explosion shock wave to the blast hole wall.

[0094] For example, there are two charging methods: forward charging and reverse charging. The primer is located at the eye opening, the energy-gathering hole faces the eye bottom, and the explosion transmission direction is from the eye opening to the eye bottom. This type of charging is forward charging, and the blasting operation with forward charging is forward blasting. Reverse charging is the opposite.

[0095] In blasting operations, reverse blasting is superior to forward blasting; it can fully utilize the energy of explosives and delay the movement of mud.

[0096] ​​High blasting efficiency. The explosive roll is located at the bottom of the eye, which can ensure that the explosive reacts fully and has large explosion energy, which is conducive to overcoming the clamping effect of the rock at the bottom of the eye. Due to the groove effect of forward blasting, the farther away from the explosive roll, the smaller the detonation speed and the smaller the blasting effect, which is not conducive to overcoming the clamping effect of the rock at the bottom of the eye. If a blind shot occurs, forward blasting is prone to blind shots, and the primer can explode outside the blasthole; while reverse blasting will not throw the explosive outside the blasthole. Judging from the flame produced by the blasting, the flame produced by reverse blasting is longer than that produced by forward blasting without gun mud. Taking into account the actual level and quality of underground workers, when millisecond blasting is used in the mining working face of high-gas mines and high-gas areas of low-gas mines, if reverse detonation is used, safety technical measures must be formulated.

[0097] Set up reasonable filling, including:

[0098] Continuous charging: Explosives are continuously loaded along the axial direction of the blasthole. When the hole depth exceeds 8m, two detonating charges (bombs) are generally arranged, one is placed 0.3-0.5m from the bottom of the hole, and the other is placed 0.5m from the top of the charge column. The advantage is simple operation; the disadvantage is that the charge column is low, and large pieces are easily produced in the uncharged part of the hole mouth.

[0099] Segmented charging: The charge column in the deep hole is divided into several sections and separated by air, rock slag or water. The advantage is that the charging height is increased and the rate of large pieces at the hole mouth is reduced; the disadvantage is that the construction is troublesome.

[0100] Bottom hole interval charging: a section of the bottom of the deep hole is left without charging, and air is used as the interval medium; in addition, there are water intervals and flexible material intervals. Air interval charging at the bottom of the hole is also called bottom hole air cushion charging.

[0101] Mixed charge: A mixed charge of high-strength explosives at the bottom of the hole and ordinary explosives at the top.

[0102] Embodiment 2, in order to further describe the technical features related to the present invention, is as follows:

[0103] (1) Static and dynamic tests on lithium ore rock mass and blastability classification.

[0104] (1.1) Static test and blasting shock wave test.

[0105] Static mechanical tests are carried out on ores with different lithology and different degrees of joint development to obtain mechanical parameters such as static tensile and compressive strength, and blasting vibration wave tests are carried out to obtain basic parameters such as wave velocity, thereby providing data support for subsequent tests.

[0106] (1.2) Dynamic mechanical properties test of rock mass.

[0107] a. Carry out dynamic mechanical properties test of ore rock, conduct dynamic compression and dynamic tensile test by SHPB dynamic impact test device, obtain dynamic crushing energy consumption curve of ore rock, and clarify the influence of the degree of development of ore rock joints on rock crushing block size and energy consumption.

[0108] b. Conduct dynamic mechanical properties tests on rock mass with confining pressure, carry out dynamic mechanical tests under uniaxial and triaxial confining pressure, obtain the stress changes and deformation characteristics of rock mass in the dynamic destruction process under geostress conditions, obtain the deformation characteristics and time curve of rock mass in the dynamic excavation process, and clarify the influence of dynamic changes of confining pressure on the mechanical properties of lithium ore rock.

[0109] (1.3) Explosibility classification.

[0110] By sorting out and analyzing many parameters such as rock compressive strength, bulk density, rock integrity and engineering geological parameters, a weight model was established through mathematical analysis software to determine the key parameters affecting rock blastability. A simple and effective lithium ore blastability classification standard was established based on the actual situation at the mine site, providing a standardized reference and system design basis for subsequent blasting parameter design.

[0111] (2) Explosion funnel test.

[0112] (2.1) Design a blasting funnel test based on the dynamic mechanical properties of the ore rock to determine the optimal unit consumption of different types of surrounding rock and ore rock and the influence of different joint development degrees on the degree of rock crushing and fragment throwing.

[0113] (2.2) Based on the results of the single-hole blasting funnel test, a multi-hole blasting funnel test was designed and a multi-hole slot blasting test was conducted to determine the effects of parameters such as hole spacing and delay time on important evaluation parameters such as the blasting funnel volume and depth.

[0114] (3) Optimization of blasting parameters for tunnel excavation.

[0115] (3.1) Optimization of slot hole blasting parameters.

[0116] (3.1.1) Research on optimization of slot blasting parameters for rock mass with developed joints. For rock mass with developed joints during tunnel excavation construction, slot blasting tests are carried out. Through numerical simulation and field tests, important parameters such as reasonable charge amount, uncoupling coefficient, number of empty holes, hole spacing, delay time, etc. in slot blasting for rock mass with developed joints are determined to improve the slotting quality and provide sufficient additional space for subsequent blasting.

[0117] (3.1.2) Research on optimization of slot hole blasting parameters for lithium ore cohesive rock mass. In order to solve the problems of high bulk rate and low rock crushing degree in the blasting process of lithium ore rock during tunnel excavation construction, slot hole blasting test was carried out. Through numerical simulation calculation and field test, important parameters such as reasonable amount of explosives, number of empty holes, hole spacing, delay time, etc. in the slot blasting of cohesive rock mass were determined to improve the slotting quality and provide sufficient additional space for subsequent blasting.

[0118] (3.2) Optimization of peripheral smooth blasting parameters.

[0119] (3.2.1) Research on optimization of smooth blasting parameters around rock masses with developed joints. Smooth blasting tests are carried out on rock masses with developed joints during tunnel excavation. Through numerical simulation and field tests, important parameters such as reasonable charge amount, uncoupling coefficient, hole spacing, and delay time in smooth blasting of rock masses with developed joints are determined to improve half-porosity and footage length, ensure the integrity of the surrounding rock of the tunnel, and enhance the safety and stability of the surrounding rock.

[0120] (3.2.2) Research on optimization of smooth blasting parameters around lithium ore viscous rock mass. In order to solve the problems of low explosiveness and low rock fragmentation during blasting of lithium ore rock in tunnel excavation construction, smooth blasting tests were carried out. Through numerical simulation calculations and field tests, important parameters such as reasonable amount of explosives, uncoupling coefficient, hole spacing, delay time, etc. in smooth blasting of viscous rock mass were determined to improve the semi-porosity and footage length, ensure the integrity of the tunnel surrounding rock, and improve the safety and stability of the surrounding rock.

[0121] (3.3) Research on full-section blasting design for tunnel excavation blasting;

[0122] (3.3.1) Research on optimization of blasting parameters for tunnel excavation in rock mass with developed joints. Combined with blasting funnel test and slotting and smooth blasting test, a reasonable tunnel excavation blasting network design is formulated. Through numerical simulation and field test, the optimal combination of parameters such as charge amount, hole spacing, delay time, and uncoupling coefficient is selected to ensure that important indicators such as tunnel advance and tunnel boundary during the construction of tunnel excavation in rock mass with developed joints meet the relevant design requirements.

[0123] (3.3.2) Research on optimization of blasting parameters for lithium mine viscous rock tunnel excavation. Combined with blasting funnel test and slotting and smooth blasting test, a reasonable tunnel excavation blasting network design is formulated. Through numerical simulation and field test, the optimal combination of parameters such as charge dosage, hole spacing, delay time, uncoupling coefficient, etc. is selected to ensure that important indicators such as tunnel advance and tunnel boundary during lithium mine viscous rock tunnel excavation construction meet relevant design requirements.

[0124] (4) Research on key technologies for single-shot blasting of upward blind shafts.

[0125] The key to the one-time well completion technology construction of upward fan-shaped cutting wells lies in the arrangement of the middle slot holes and the surrounding polished holes. The reasonable center slot hole diameter and hole arrangement method are selected to ensure the slotting quality, and the blasting parameters such as the non-coupling coefficient of the surrounding holes, hole spacing and delay time are calculated to ensure that the size and quality of the cutting well meet the subsequent construction requirements.

[0126] 1) Study on slotting blasting parameters.

[0127] a. Determine the scope of the explosion stress wave fissure zone. Slot blasting is carried out under the condition of only one free surface, and it is difficult to break the rock by blasting. The present invention can regard its rock breaking effect as the superposition of the blasting effects of each slot hole. The slot hole charges detonated at the same time form radial and circumferential cracks around the blast hole, and converge into a spatial crack network in the slot cavity, which cuts the rock into fragments and throws them out under the expansion of the detonation gas. Therefore, to ensure that the rock is fully broken, the arrangement circle diameter of the slot hole must meet the design requirements.

[0128] b. Deep hole linear slotting uses the space of empty holes to provide free surface and compensation space for the blasted rock. Therefore, the reserved space for each slotting blasting should meet the rock crushing requirements. The blasting compensation space requirements of the ore rock are determined through numerical simulation and field tests to ensure the ore rock crushing effect. The number of intermediate empty holes and the hole layout are determined through field tests.

[0129] 2) Study on blind shaft blasting parameters.

[0130] After the project is launched, 3-5 optimization schemes will be comprehensively determined based on the mine rock mechanics parameters, numerical simulation results, and calculation results of the blasting stress wave fracture circle determination method and the compensation space method, and field test research will be carried out.

[0131] a. Determine the slotting method. At present, the commonly used slotting methods in mines include nine-hole slotting, prism-shaped slotting, barrel-shaped slotting, etc. According to the existing operating equipment in the mine and the results of numerical simulation calculation and analysis, the best slotting scheme suitable for lithium ore rock is selected and field tests are carried out to determine the slotting form, number of empty holes, distance between empty holes and charging holes, filling length and other parameters.

[0132] b. Calculation of charge quantity: determine the reasonable charge quantity and decoupling coefficient of the slot hole and surrounding holes through numerical simulation calculation and blasting funnel test results.

[0133] c. Determine the delay time and use numerical simulation to calculate the optimal impact time of the inter-hole delay on the superposition of the explosion stress wave, so that the destructive effect of the stress wave on the rock can be optimized.

[0134] d. Filling and charging. Since upward uncoupled charging is used, it is necessary to study reasonable charging methods to ensure the accuracy of charging quantity and explosive position, and set reasonable filling to ensure that the explosive energy fully acts on the blasted rock mass.

[0135] Embodiment 3, the related technologies involved in the present invention also include:

[0136] (1) Static and dynamic mechanical properties test of rock.

[0137] Analysis of rock foundation mechanical properties: In order to obtain the basic mechanical parameters of the rock in the underground mine study area, the YAW-600 pressure testing machine was used to conduct static tests on the rock to determine the mechanical parameters of the specimen, such as uniaxial compression strength, conventional triaxial compression strength, shear resistance, tension, elastic modulus, etc. The experimental process was carried out in accordance with the test method recommended by the "Railway Engineering Rock Test Code" (TB10115-2014). The RSM-SY5 blasting vibration wave tester and its matching longitudinal wave transducer were used to measure the longitudinal wave velocity of the rock.

[0138] This test requires applying different axial pressures and confining pressures to the rock specimens, and requires equipment with active confining pressure loading function. Therefore, a three-dimensional SHPB test system from a university was finally selected, which can apply active confining pressure in the range of 0-100MPa and axial static pressure in the range of 0-200MPa to the rock specimens, can generate an impact load of 0-500MPa, and can achieve a wide range of high strain rate (100-103s-1) loading. The test was completed in a rock mechanics laboratory of a university.

[0139] (2) Classification of explosiveness of mineral rocks.

[0140] Rock blastability refers to the resistance of rock to blasting or the difficulty of blasting rock. It is a comprehensive reflection of the physical and mechanical properties of rock under dynamic load. Explosibility classification is to divide rock into grades of blastability based on quantitative indicators of rock blastability. It is an important basis for formulating blasting quotas, selecting blasting parameters, and conducting blasting design. It is also one of the scientific bases for the management of mining enterprises. Engineering practice has proved that the establishment of reasonable classification standards has a significant effect on improving the quality of blasting construction, accelerating project progress, and reducing construction costs. Therefore, it is of great significance to accurately classify the blastability of rock mass. The commonly used quantitative methods are as follows:

[0141] 1) Pusch rock solidity classification.

[0142] Pusch classification method. The rock strength coefficient f represents the relative value of rock resistance to crushing. Because rock has the strongest compressive resistance, 1 / 10 of the rock's uniaxial compressive strength limit is taken as the rock's strength coefficient. The calculation formula of the rock strength coefficient is simple and clear. The f value can be used to predict the rock's ability to resist crushing and its stability after drilling. According to the rock strength coefficient f, the rock can be divided into 10 levels. The higher the level, the easier it is to break.

[0143] 2) Single factor classification method for explosiveness.

[0144] a. Classification by wave impedance.

[0145] The wave impedance of rock is the product of the longitudinal wave velocity and the rock density. It means the unit movement velocity of the center of mass of the rock body during blasting, and the magnitude of the stress that can be derived in the rock. AH Khanukayev studied the wave impedance of rock as the basis for blasting classification, which is a major progress in the study of rock blasting, because this indicator is measured in the rock mass on site, and the test instrument and test method are relatively simple. A large number of experimental studies have shown that the wave impedance of rock mass is not only related to the physical and mechanical properties of rock, but also depends on the fracture structure characteristics of rock.

[0146] b. Estimate the size of the blasting blocks.

[0147] Different unit consumption of explosives will produce different bulk rates. Rubtsov stipulated the following standard blasting conditions: the diameter of the blasthole is not greater than 0.02 times the step height, the number of single-row blasting holes is not less than 5, the super-depth is not greater than 0.15 times the chassis resistance line, the blasthole proximity coefficient is 1, No. 6 waterproof ammonium nitrate explosive is used, continuous charging, the filling coefficient is 0.5, and instantaneous detonation.

[0148] c. Standard explosive consumption q classification.

[0149] Rizhewski suggested that the explosiveness of rock be determined by the standard explosive consumption q, which is closely related to the cracks.

[0150] d. Optimal blasting funnel index.

[0151] CW Livingston developed a method to determine rock explosiveness through blasting funnel experiments when studying the law of loose blasting funnels. Livingston used the relationship that the minimum resistance line is proportional to the cube root of the amount of explosive.

[0152] 3) Multi-factor classification method for explosiveness.

[0153] a. Comprehensive explosiveness classification.

[0154] This classification method combines multiple factors such as explosive consumption, rock strength and rock mass cracks, with explosive consumption as the main factor. The standard conditions for explosive consumption are: step height 10-15m, blast hole diameter 243mm. Ammonium ladder explosive, explosion heat 4190KJ / Kg. A large amount of statistical data shows that the deviation (mean square error) of explosive consumption is proportional to the 2 / 3 power of explosive consumption.

[0155] b. Comprehensive classification of rock explosiveness.

[0156] This classification method mainly considers the volume of the blasting funnel, the distribution of blasting fragments, and the relationship between rock wave impedance and rock blastability. The standard conditions are as follows: directly select a representative rock section at the blasting site of the mine to be classified, and drill vertical holes on a relatively complete rock mass with a free surface. The blasthole diameter is 45mm, the hole depth is 1m, and the hole spacing is 2m; No. 2 rock ammonium nitrate explosive is used, the charge amount per hole is 0.45Kg, continuous charging, gun mud plugging, and one No. 8 detonator is detonated. Test method: Before charging, use a blasting vibration wave meter to measure the elastic longitudinal wave velocity of the rock mass. After charging and blasting, measure the large block rate (greater than 300mm), small block rate (less than 50mm), and average qualified rate (accumulated average value of fragments of 50-100mm, 100-200mm and 200-300mm) of the blasting pile rock, and measure and calculate the volume of the blasting funnel.

[0157] 4) Rock blastability classification using grey system theory.

[0158] a. Selection of grading indicators.

[0159] There are dozens of factors that affect the quality of rock blasting, and their combined effect determines the quality of rock blasting. However, due to the different purposes of theoretical analysis and field tests, and the limitations of various objective conditions, it is impossible and unnecessary to reflect all the influencing factors. Therefore, how to simply and reliably determine the main factors affecting the quality of rock blasting from many factors has become a basic problem in the theoretical and applied research of rock blasting, and is also a prerequisite for accurately controlling and predicting the quality of blasting. In the actual engineering system, only part of the attributes or properties of the system are often known, while the other part of the properties are unknown or uncertain. Therefore, the rock engineering geological system can be considered as a gray system. When it is required to judge the blastability level of the system, according to the gray system theory, this is actually a hierarchical decision clustering problem. At this time, the gray parameter is used to describe the system, that is, the grading index of the blastability level is expressed by the gray number. In this way, the gray clustering method in the gray system theory can be used to judge the blastability of rock.

[0160] The following two principles are followed: (1) it can reflect the explosive properties of the rock mass more comprehensively from different aspects; (2) it can be easily obtained through experiments or field tests. The rock strength coefficient f, the wave impedance of the rock, the unit consumption of explosives and the average crack spacing of the rock mass can be used as evaluation indicators for the explosiveness of the rock.

[0161] b. Grey clustering classification of rock blastability.

[0162] Let k = 1, 2, 3, 4, 5 be typical categories, i = Ⅰ, Ⅱ, Ⅲ, Ⅳ be clustering elements, and j = 1#, 2#, 3#, 4# be clustering indices. Grey clustering classification method is to distinguish the categories to which clustering elements belong under clustering indices.

[0163] Firstly, according to the research results and habits of rock blastability classification, rocks are divided into five typical categories according to the difficulty of blastability, namely, easy to explode, medium to explode, difficult to explode and extremely difficult to explode. According to the grey system theory, they are regarded as typical categories k, k{1, 2, 3, 4, 5}, and the factors affecting rock blastability are summarized into four indicators as clustering indicators j, j(1#, 2#, 3#, 4#), and the rock mass to be evaluated is regarded as clustering elements i, i{Ⅰ, Ⅱ, Ⅲ, Ⅳ}.

[0164] It is very important to choose a classification method for the explosiveness level of the lithium ore rock blasting project in Dangba Mining Area, which directly affects whether the explosiveness can be accurately used to guide the construction.

[0165] (3) Explosion funnel test.

[0166] 1) Single hole blasting funnel test.

[0167] The blastholes are arranged on the waistline of the test tunnel, that is, 1.2m away from the tunnel floor. The rock drill drills 18 (two groups) Φ40mm blastholes vertically on the tunnel side, with a drilling spacing of 1.5m. The designed blasthole depths are: 0.40m, 0.65m, 0.50m, 0.55m, 0.60m, 0.65m, 0.70m, 0.80m, 0.90m; the blastholes are arranged vertically on the free surface.

[0168] In order to ensure the reliability of the data obtained from the blasting funnel test, the rock powder left in the blasthole should be blown clean with water before charging, and the blasthole filling should be strictly filled in accordance with the design requirements. Therefore, after charging, it must be filled with gun mud that meets the safety requirements and tamped. Gun mud is commonly used in a ratio of 1:3 mud and sand, with a humidity of 18% to 20%. This kind of gun mud has both good plasticity and a large friction coefficient. The blasting is initiated by digital electronic detonators, and one hole is blasted each time. Through the single-hole blasting funnel test, the optimal blasting funnel depth is sought;

[0169] 2) The purpose of conducting variable hole spacing multi-hole same-section blasting funnel test is to study the blasting conditions of the ore and rock at the bottom of the blasting funnel formed when the hole spacing of two adjacent blast holes changes, so as to determine the reasonable range of the hole bottom distance and provide a basis for the subsequent design of the parameters of the deep stope blasting hole network. The optimal blasting funnel depth obtained from the single hole blasting funnel test was selected as the charging depth, and the variable hole spacing same-section blasting funnel test was carried out to calculate the unit explosive consumption q under the same-section blasting condition. In the variable hole spacing same-section blasting test, the blast hole spacing was designed to be a multiple of the optimal blasting funnel radius, and multi-hole same-section blasting was carried out, and the blast holes were perpendicular to the tunnel side.

[0170] 3) According to the blasting principle, when the charge is blasted, when the minimum resistance line is less than or equal to the radius of its destruction zone, the rock will be thrown or exploded, and when the resistance line is greater than its destruction radius, the charge will only produce internal explosion and cannot blast the charge to the rock on the free surface. Therefore, the resistance line is an important parameter of blasting. Based on this, the design lowers the parameters of horizontal medium and deep hole blasting, ore-gathering slot blasting, and eastern boundary deep hole blasting.

[0171] (4) Slot blasting parameters.

[0172] a. Determine the scope of the explosion stress wave fracture zone. Slot blasting is carried out under the condition of only one free surface. It is difficult to break the rock by blasting. Its rock breaking effect can be regarded as the superposition of the blasting effects of each slot hole. The slot hole charges detonated at the same time form radial and circumferential fractures around the blast hole, and converge into a spatial fracture network in the slot cavity, which cuts the rock into fragments and throws them out under the expansion of the detonation gas. Therefore, to ensure that the rock is fully broken, the arrangement diameter of the slot hole must meet the design requirements.

[0173] b. Deep hole linear slotting uses the space of empty holes to provide free surface and additional space for the blasted rock. Therefore, the reserved space for each slotting blasting should meet the requirements of rock crushing and expansion. The blasting additional space requirements of the ore rock are determined through numerical simulation and field tests to ensure the ore rock crushing effect. The number of intermediate empty holes and the hole layout are determined through field tests.

[0174] (5) Numerical simulation technology.

[0175] Based on the above research results, blasting plans for different blasting areas were determined, and industrial experiments were carried out to statistically analyze the blasting effects and verify the optimal blasting parameter group.

[0176] 1) Research on tunnel excavation blasting parameters and process optimization.

[0177] a. First of all, on-site construction personnel must be required to carry out construction according to the accurate hole layout position to ensure that the qualified rate of the slot holes and peripheral holes constructed meets the design requirements.

[0178] b. Optimize the blasting sequence of blast holes. Through the analysis of the current blasting network, it is found that there are unreasonable places in the blasting sequence of blast holes, which is easy to cause problems such as blasting clamping. The blasting sequence and delay time of the blast holes must be adjusted. The blast holes should be detonated in the order of forming a small free surface to transfer a large free surface.

[0179] c. Based on the basic theory, rock blastability classification and numerical simulation research results, optimization research is conducted on parameters such as blasting hole depth, angle, and hole bottom distance to reduce the probability of adverse effects of blasting and ensure production safety.

[0180] A university laboratory is equipped with relatively complete test equipment, including DH3817 dynamic and static strain test system, RSM-SY5 (T) non-metallic blasting vibration wave detector, digital super blasting vibration wave flaw detector (CTS-2000Plus), IDT high-speed camera, press, three-dimensional dynamic and static combination SHPB and other experimental and testing equipment, which can provide support for the static load and cyclic dynamic load combined impact mechanics test of the present invention. Based on the physical and mechanical parameters and explosiveness levels measured by different minerals and rocks, the present invention studies different blasting parameter combinations for various blasting operation requirements in different regions and environments, and can provide system support for mine blasting operations;

[0181] By studying the influence of relevant parameters such as explosive consumption, minimum resistance line and uncoupling coefficient on blasting effect, and establishing corresponding calculation models, it can enrich the theory of broken rock movement and guide the development of parameter optimization work.

[0182] The blasting parameter design system of the present invention can reduce the economic investment of enterprises in underground mine blasting, reduce production costs, improve operation efficiency, and improve safety and economy. It has important theoretical and practical significance for ensuring safe production in mines and improving economic benefits.

[0183] (6) Material constitutive model and parameter determination

[0184] a. Rock mass constitutive model and parameters: The rock material model adopts "*MAT_PLASTIC_KINEMATIC" or "MAT_HJC" and other constitutive models. The specific parameters will be determined according to the static and dynamic mechanical test results of the rock after the project is carried out.

[0185] b. Explosive material model: In ANSYS / LS-DYNA, the explosive material model uses the high-energy explosive material model "*MAT_HIGH_EXPLOSIVE_BURN" and uses the JWL state equation to simulate the explosion of explosives during the blasting process. Its parameters are shown in Table 1.

[0186] Table 1 Explosive material model parameters

[0187]

[0188] The JWL state equation relationship when the explosive explodes is:

[0189]

[0190] Where P is pressure, ω, R 1 ,R 2 are all material constants, V is the relative volume, E 0 is the internal energy per unit volume; the parameters are shown in Table 2.

[0191] Table 2 Parameters of JWL state equation

[0192] Mat A / (Gpa) B / (Gpa) <![CDATA[R 1 ]]> <![CDATA[R 2 ]]> ω E / (Gpa) <![CDATA[V 0 ]]> Explosives 214 1.82 4.16 0.96 0.3 4.192 0

[0193] c. Air material model

[0194] The air material model uses the blank material “*MAT_NULL”, and its parameters are shown in Table 3.

[0195] Table 3 Air material model parameters

[0196] Mat <![CDATA[ρ(kg·m -3 )]]> pc mu Terod cerod ym pr rock 1.29 0 0 0 0 0 0

[0197] The LINEAR-POLYNOMIAL state equation of air fluid is:

[0198] P=C 0 +C 1 μ+C 2 μ 2 +C 3 μ 3 +(C 4 +C 5 μ+C 6 μ 2 )E 0

[0199]

[0200] In the formula, C 0 ,C 1 ,C 2 ,C 3 ,C 4 ,C 5 ,C 6 are real constants, ρ is the standard density, ρ 0 is the reference density, E 0 is the internal energy per unit volume; the parameters in the formula are shown in Table 4.

[0201] Table 4 Parameters of LINEAR-POLYNOMIAL equation of state

[0202] Mat <![CDATA[C 0 ]]> <![CDATA[C 1 ]]> <![CDATA[C 2 ]]> <![CDATA[C 3 ]]> <![CDATA[C 4 ]]> <![CDATA[C 5 ]]> <![CDATA[C 6 ]]> <![CDATA[E 0 ]]> <![CDATA[V 0 ]]> Air <![CDATA[-1E -6 ]]> 0 0 0 0.4 0.4 0 <![CDATA[2.5E -6 ]]> 0

[0203] Embodiment 2, as Figure 2 As shown, the blasting parameter screening system in the blind well primary well completion blasting provided by the embodiment of the present invention comprises:

[0204] The slotting method determination module 1 is used to select a slotting scheme suitable for lithium ore and conduct field tests according to the mining operation equipment and numerical simulation calculation and analysis results, and determine the parameters of the slotting form, the number of empty holes, the distance between the empty holes and the charging holes, and the filling length;

[0205] The decoupling coefficient determination module 2 is used to determine the charge amount and decoupling coefficient of the slot hole and the surrounding holes through numerical simulation calculation and blasting funnel test results;

[0206] The hole delay determination module 3 is used to calculate the influence time of the hole delay on the superposition of the explosion stress wave by numerical simulation, so as to achieve the destruction of the rock by the stress wave;

[0207] The packing and charging module 4 is used to determine the charging method to ensure the accuracy of the charging amount and the position of the explosives, and to set reasonable packing to ensure that the energy of the explosives fully acts on the blasted rock mass.

[0208] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for screening blasting parameters in a blind well primary blasting, characterized in that: The method comprises the steps of: S1, determine the slotting method, select the slotting scheme suitable for lithium ore rock according to the mining operation equipment and numerical simulation calculation and analysis results, and conduct field tests to determine the parameters of slotting form, number of empty holes, distance between empty holes and charging holes, and filling length; S2, calculate the charge amount, determine the charge amount and uncoupling coefficient of the slot hole and surrounding holes through numerical simulation calculation and blasting funnel test results; S3, determine the delay time, use numerical simulation to calculate the influence time of the inter-hole delay on the superposition of the explosion stress wave, and realize the destruction of the rock by the stress wave; S4, filling and charging, determine the charging method to ensure the accuracy of the charging amount and the position of the explosives, and set up reasonable filling to ensure that the explosive energy fully acts on the blasted rock mass.

2. The method for screening blasting parameters in blind well primary blasting according to claim 1, characterized in that: In step S2, the decoupling coefficient is the ratio of the borehole diameter to the charge diameter; the decoupling coefficient is 1.5 to 3.0; the peripheral hole spacing is 10 to 20 times the borehole diameter; the borehole density coefficient of the peripheral holes is 0.8 to 1.0; the charge concentration of the peripheral holes is 70 to 120 kg / m in soft rock, 100 to 150 kg / m in medium hard rock, and 150 to 250 kg / m in hard rock.

3. The method for screening blasting parameters in blind well primary blasting according to claim 2, characterized in that: Methods for determining the uncoupling coefficient include: According to the preliminarily determined ratio of the uncoupled blasthole diameter to the charge diameter, the uncoupling coefficient of the rock mass is preset. After the uncoupled charge type explosive material model is determined, the established JWL state equation of explosion and the LINEAR-POLYNONIAL state equation of air fluid are used to calculate whether the tangential tensile stress generated by the uncoupled charge type explosive material model with different uncoupling coefficients is greater than the tensile strength of the rock. The ratio of the uncoupled blasthole diameter to the charge diameter of the rock mass and the uncoupling coefficient that meet the energy and resolution are determined as the optimized uncoupled charge type explosive material model to generate directional fracture parameters.

4. The method for screening blasting parameters in blind well primary blasting according to claim 3, characterized in that: For uncoupled charge explosive material models with different uncoupled coefficients, the tangential tensile stress generated by the excitation is calculated to see whether it is greater than the tensile strength of the rock, including: (1) During the explosion process, the explosive material model is simplified to an incompressible Newtonian explosion fluid, and the differential equation of motion of the explosion fluid is obtained based on Newton's second law. The continuity equation is derived from the mass conservation equation in the volume element, and the formula for the instantaneous tangential tensile stress generated by the explosion fluid is obtained. The tangential tensile stress distribution of the fluid in the calculated slot hole should be coupled with the flow field and pressure field. (2) After the explosive material model explodes, the tangential tensile stress generated during the conversion into air fluid is determined by the tangential tensile stress pressure conduction equation; (3) During the generation of explosive cracks, the rock mass is simplified into a rigid deformation model. Before the rock mass reaches the fracture strength, the tangential tensile stress-strain generated by the explosive material model is linearly related. After the stress reaches the fracture strength of the rock mass, it remains constant. The final strain is the sum of the fracture strain and the crack strain.

5. The method for screening blasting parameters in blind well primary blasting according to claim 4, characterized in that: In step (1), the differential equation of motion of the explosion fluid is obtained according to Newton's second law, and the expression is: Where ρ' is the density of the explosion fluid, o, c, f are the pressure velocity components of the explosion fluid in the x, y, z axes respectively, e is the explosion movement time of the explosion fluid, h is the unit volume pressure of the explosion fluid, kx, ky, kz are the explosion pressure acceleration components in the three coordinate axis directions respectively, δ is the density of the explosion fluid after the explosion movement, is the Laplace operator.

6. The method for screening blasting parameters in blind well primary blasting according to claim 5, characterized in that: In step (1), the continuity equation derived from the mass conservation equation in the volume element is used to obtain the formula for the instantaneous tangential tensile stress generated by the explosion fluid, which is expressed as follows: Where, I is the dispersion of the explosion fluid; The tangential tensile stress distribution of the fluid in the computational slot hole should be coupled with the flow field and the pressure field, and the energy equation is as follows: In the formula, is the slope of the tangential tensile stress-pressure curve of the explosive material model, A is the tangential tensile stress, and J is the pressure conductivity of the explosive material model.

7. The method for screening blasting parameters in blind well primary blasting according to claim 6, characterized in that: In step (2), after the explosive material model explodes, the tangential tensile stress generated during the conversion into air fluid is determined by the tangential tensile stress pressure conduction equation, which is expressed as: Where r is the internal energy of the explosive material model.

8. The method for screening blasting parameters in blind well primary blasting according to claim 7, characterized in that: In step (3), the final strain is the sum of the fracture strain and the crack strain, expressed as: In the formula, is the theoretical stress of rock mass, E is the modulus of rupture, is the theoretical strain of rock mass, η s is the stress when cracks occur in the rock mass, is the strength of the rock mass at fracture, They are the corresponding strain when the rock mass breaks and the subsequent crack strain.

9. The method for screening blasting parameters in blind well primary blasting according to claim 1, characterized in that: In step S3, the extension time is determined, including the steps of: S301, through the three-dimensional lithium ore rock structure map, determine the blast hole axial height difference D and the straight line distance l between the blast hole explosion center in the blasting area of ​​the ore rock pre-blasting area; measure the shear wave velocity u of the blasting vibration wave in the rock mass h and the longitudinal wave velocity u z ; The structural influence coefficient G2 and the blasthole axial height influence coefficient χ are determined through blasting vibration monitoring; The vibration damping ratio in the same precise time-delay controlled blasting is the same. The blasting vibration velocity is affected by the axial height condition of the blasthole. The blasting vibration velocity is expressed as: U (s) =sinθ×G2(D / l) χ Where U (s) is the blasting vibration velocity, θ is the angle formed by the axial height difference D of the blasthole and the straight-line distance l; S302, according to the calculation formula of blasting vibration velocity, the vibration frequency of the center of mass of the lithium ore rock mass body conforms to the dimensional analysis theorem and the π theorem. According to the straight-line distance between the ore rock pre-blasting area and the blast hole blast center and the axial height difference of the blast hole, the vibration frequency q of the center of mass of the lithium ore rock mass body is calculated as: q=F·G2(D / l) χ Where F is the frequency coefficient; S303, by setting the delay time between holes, the adjacent vibration waveforms are N / 4 cycles apart when they arrive at the designated blasthole node, where N is an integer, so that the peaks of the two waveforms meet when the waveforms arrive at the position, thereby superimposing the amplitudes. The delay time between holes is calculated as follows: According to the calculation formula of the vibration frequency of the center of mass of lithium ore rock mass, the distance between the pre-blasting area of ​​ore rock and the blasthole is l1, l2…l n , l1<l2<…<l n , the axial height difference of the blasthole is D1, D2…D n , the blast hole detonation time is s1, s2…s n , s1 <s2<…<s n ; At the same time, the distance difference between the blasthole and the pre-blasting area of ​​the ore rock is Δl = l n -l n-1 , the interval time between holes is Δs=s n -s n-1 ; The expression is: In the formula, l n is the distance between the ore pre-blasting area and the nth blast hole, l n-1 is the distance between the ore rock pre-blasting area and the n-1th blast hole, s n is the detonation time of the nth blast hole, s n-1 is the detonation time of the n-1th blast hole.

10. A blasting parameter screening system for blind well primary well blasting, characterized in that: The system implements the method for screening blasting parameters in a blind well primary blasting as claimed in any one of claims 1 to 9, and the system comprises: The slotting method determination module (1) is used to select a slotting scheme suitable for lithium ore and conduct field tests based on mining equipment and numerical simulation analysis results to determine the parameters of the slotting form, the number of empty holes, the distance between the empty holes and the charging holes, and the filling length; The decoupling coefficient determination module (2) is used to determine the charge amount and decoupling coefficient of the cut hole and the surrounding holes through numerical simulation calculation and blasting funnel test results; The hole delay determination module (3) is used to calculate the influence time of the hole delay on the superposition effect of the explosion stress wave by numerical simulation, so as to achieve the destruction of the rock by the stress wave; The packing and charging module (4) is used to determine the charging method to ensure the accuracy of the charging amount and the explosive position, and to set reasonable packing to ensure that the explosive energy fully acts on the blasted rock mass.

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