Hard rock mine goaf lateral stress regulation deep hole blasting roof unloading method

Abstract

The present application relates to the technical field of mine exploitation, and more particularly to a deep-hole blasting roof breaking and pressure releasing method for lateral stress regulation of a hard rock mine goaf, comprising the following steps: S100, obtaining a vertical distance H of a key layer from a mineral body; S200, determining a position h1 of a peak value of a working face advance support pressure, a support pressure influence range h2, a position h3 of a peak value of a goaf lateral support pressure, and a support pressure influence range h4; S300, determining a position of blasting pressure release in the key layer; S400, drilling a plurality of holes into the main control layer according to the position in step S300, filling explosives in the holes, and cutting off the key layer by using a blasting method after hole sealing; and S500, monitoring a working face stress and energy evolution law after roof blasting in real time, and then optimizing a design hole arrangement distance. The present application is beneficial to blocking a transmission path of overburden rock strata load of the goaf to the working face direction under the premise of maintaining the integrity of the roadway surrounding rock, so as to weaken the advance mining stress influence of the working face.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mine exploitation, and in particular to a deep-hole blasting roof breaking and pressure releasing method for lateral stress regulation and control of a hard rock mine goaf. BACKGROUND

[0002] Mine exploitation is a process of exploiting ore raw materials from underground or the ground surface, and is an important and complex process of the mining industry, involving multiple technologies and needing to be carried out on the premise of ensuring safety and environmental protection. The exploitation depth of mines in China is gradually increasing, which leads to an increase in the ground stress of mines, which makes more and more working faces face the problem of stress concentration, and is prone to rock-burst accidents.

[0003] The pressure releasing methods in the prior art mainly include hydraulic fracturing pressure release, conventional blasting pressure release, roof pre-splitting pressure release and the like. If hydraulic fracturing pressure release is used, it will lead to poor compatibility of the fracturing fluid with the stratum, large filtration loss of dense rock layers (such as argillaceous cover layers), difficulty of the fracturing fluid in effectively infiltrating, high wellhead pressure and difficulty in fracturing the stratum, and damage to the proppant flow conductivity and the natural fracture system. If conventional blasting pressure release is used, it will lead to incomplete pressure release, repeated hole reaming, delay of the mining and excavation progress, complex process, high safety risk and influence on the continuity of exploitation. If the roof pre-splitting pressure release method is used, it is difficult to break thick and hard roofs, and the increase in the cantilever length will significantly magnify the wall support pressure, which will exceed the strength limit of the filling body, cause the wall to collapse, the deformation of the roadway to multiply, and the pre-splitting zone and the roof fracture surface to be misaligned, and it is difficult to form a continuous weakened surface.

[0004] The working face exploitation will cause the overburden stratum of the goaf to generate an advanced support pressure, especially when the working face is advanced along the goaf, the lateral support pressure of the goaf on the side and the advanced support stress of the working face are superimposed, which will cause serious damage to the roadway on the side along the goaf. The distribution of the support stress is affected by multiple factors, such as the working face depth, the basic roof thickness, the immediate roof thickness and the lithology, and changes constantly with the working face advancing.

[0005] When the roadway is in the influence range of the advanced abutment pressure for a long time, it will bring great threat to the stability and safety of the roadway. Among them, the "advanced abutment pressure" refers to a stress concentration phenomenon in a certain range in front of the working face during the mining process of the mine, which is caused by the breaking of the rock mechanical balance. Under the action of this continuous stress, serious deformation of the roadway will occur, including rib spalling, roof falling and floor heave. "Rib spalling" refers to the collapse of the rock mass on both sides of the roadway due to the inability to withstand the surrounding stress; "roof falling" refers to the collapse of the roof rock mass of the roadway; "floor heave" refers to the upward bulging of the floor of the roadway due to pressure. If these deformation problems cannot be effectively controlled in time, serious accidents such as water inrush, rock burst and gas outburst will easily occur. For example, roof falling may damage the normal structure of the roadway, causing underground water to flow into the roadway and causing water inrush accidents; rock burst is caused by the sudden release of high stress accumulated in the rock mass, which causes the rock mass to suddenly eject, posing a great threat to personnel and equipment; gas outburst in a high-pressure gas area will easily cause serious consequences such as explosion, thus posing a great risk to the safety of personnel, and also causing great loss to the equipment, facilities and resources of the mine, affecting the normal production order of the mine, and bringing great economic burden and social influence.

[0006] Therefore, the technical personnel in the field are committed to developing a deep hole blasting top breaking pressure relief method for lateral stress regulation of hard rock mine goaf, which is beneficial to block the transmission path of the overburden load of the goaf to the working face direction under the premise of maintaining the integrity of the roadway surrounding rock, so as to weaken the influence of the advanced mining stress of the working face, thereby greatly improving the stability of the roadway and ensuring the purpose of safe mining. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a deep hole blasting top breaking pressure relief method for lateral stress regulation of hard rock mine goaf, which is beneficial to block the transmission path of the overburden load of the goaf to the working face direction under the premise of maintaining the integrity of the roadway surrounding rock, so as to weaken the influence of the advanced mining stress of the working face, thereby greatly improving the stability of the roadway and ensuring the purpose of safe mining.

[0008] The technical solution of the present application to solve the above technical problem is as follows:

[0009] A deep hole blasting top breaking pressure relief method for lateral stress regulation of hard rock mine goaf, comprising the following steps:

[0010] S100. According to the drill column chart obtained from the mine geological data or rock core experiment, the number of layers, thickness, lithology and physical and mechanical parameters of the rock layer above the ore body of the working face are obtained, and the vertical distance H of the key layer from the ore body is obtained according to the previous observation and analysis of the ground subsidence and roof falling of the goaf;

[0011] S200. Establishing a numerical simulation model of the working face and the gob on one side according to the overburden rock parameters obtained from the borehole column chart, and determining the peak position h1 of the abutment pressure in front of the working face, the influence range h2 of the abutment pressure, the peak position h3 of the lateral abutment pressure in the gob, and the influence range h4 of the lateral abutment pressure in the gob in combination with the microseismic monitoring data.

[0012] the peak position h1 of the abutment pressure in front of the working face;

[0013] the influence range h2 of the abutment pressure;

[0014] the peak position h3 of the lateral abutment pressure in the gob;

[0015] the influence range h4 of the lateral abutment pressure in the gob;

[0016] S300. Determining the position of blasting pressure relief at the key layer;

[0017] S400. Drilling a plurality of boreholes into the main control layer according to the position in step S300, filling explosives in the boreholes, and cutting off the key layer by using the blasting method after sealing the boreholes;

[0018] S500. Real-time monitoring the stress and energy evolution law of the working face after the roof blasting, and optimizing the design of the borehole layout distance.

[0019] The beneficial effects of the above scheme are: according to the borehole column chart obtained from the mine geological data or the rock coring experiment, the number of layers, thickness, lithology and physical and mechanical parameters of the rock layer above the ore body of the working face are comprehensively understood, and the vertical distance H of the key layer from the ore body is determined in combination with the relevant observation data of the previous gob. On this basis, the numerical simulation model is established by using the overburden rock parameters and combined with the microseismic monitoring data, the peak position h1 of the abutment pressure in front of the working face, the influence range h2, the peak position h3 of the lateral abutment pressure in the gob, and the influence range h4 are accurately determined, which provides a scientific and accurate basis for the determination of the blasting pressure relief position, and ensures that the blasting operation can be targeted to act on the key area, effectively improving the pressure relief effect;

[0020] By determining the blasting pressure relief position at the key layer, drilling a plurality of boreholes into the main control layer, filling explosives in the boreholes, and then blasting, the key layer can be cut off, and the transmission path of the load of the overburden rock layer in the gob to the working face direction is blocked, thereby significantly reducing the influence of the working face on the working face by the advanced mining stress, effectively avoiding problems such as serious deformation of the roadway caused by stress concentration, such as spalling, roof falling and floor heaving, greatly reducing the risk of major accidents such as water inrush, rock burst and gas outburst, and effectively ensuring the stability of the roadway and the safety of the mining process;

[0021] Real-time monitoring is conducted on the stress and energy evolution law of the working face after the roof blasting, the drilling arrangement distance is optimized in time according to the monitoring data, the blasting pressure relief scheme can be dynamically adjusted according to the actual stress change, the pressure relief effect is further improved, meanwhile, the problems of resource waste or insufficient pressure relief caused by unreasonable drilling arrangement can be avoided, the long-term stability and safety of the roadway in the mining process are ensured, and safe and efficient mining operation is beneficial to be realized.

[0022] Based on the above technical solutions, the application can be further improved as follows.

[0023] Further, in step S300, the following steps are specifically included:

[0024] S301. In front of the open-off cut, the working face length is L, every 10m, a blasting hole is arranged, wherein:

[0025] The number of drilling holes: N1=L / 10;

[0026] Drilling angle: alpha1=arctan alpha6; alpha6=H / h1;

[0027] Drilling depth: l1=H / sin alpha1;

[0028] S302. Along the two sides of the gob roadway, the drilling holes are arranged outward at the position h1 of the working face pre-support pressure peak value, and the arrangement range is within the open-off cut to the pre-support pressure influence range h2 of the working face;

[0029] Every 15m, a drilling hole is arranged on the side of the roadway along the goaf during the tunneling, and every 15m, a drilling hole is arranged on the side of the roadway along the goaf during the mining, two drilling holes are arranged every 15m on the side of the mining face, and the distance between the side of the roadway along the goaf and the goaf is l, wherein

[0030] On the side of the roadway along the goaf:

[0031] The number of drilling holes: N2=h2 / 7.5;

[0032] Drilling angle: alpha2=arctan alpha7; alpha7=H / l;

[0033] Drilling depth: l2=H / sin alpha2;

[0034] On the side of the mining face:

[0035] The number of drilling holes 1: N3=h2 / 15

[0036] Drilling hole 1 angle: alpha3=arctan alpha8; alpha8=H / h3;

[0037] Drilling hole 1 depth: l3=H / sin alpha3;

[0038] The number of drilling holes 2: N4=N3;

[0039] Drilling hole 2 angle: a4=arctan a9; a9=H / h4;

[0040] Drilling hole 2 depth: l4=H / sin a4;

[0041] S303. The entity pillar roadway is arranged outward at the position h1 of the peak value of the working face advance support pressure, the arrangement range is within the open-off cut to the working face advance support pressure influence range h2, and one blasting pressure relief drilling hole is arranged every 15m along the working face dip on each stope side, the arrangement parameters are the same as the drilling hole 2 on the stope side of the gob-side entry, and meanwhile, drilling holes are arranged every 7.5m along the working face trend in the middle part of the roadway according to the site anti-scour experience, wherein,

[0042] Drilling hole number: N5= h2 / 7.5;

[0043] Drilling hole angle: a5=80°;

[0044] Drilling hole depth: l5=H / sin a5.

[0045] The beneficial effects of the above further scheme are: the specific drilling hole parameters are determined according to the working face length, the advance support pressure related parameters and the like, the precise arrangement of the drilling holes is realized, the blasting energy can be precisely acted on the key stratum, the effect of the blasting roof breaking and pressure relief is effectively improved, and the resource waste or insufficient pressure relief caused by blind drilling hole arrangement is avoided.

[0046] The drilling hole arrangement of the entity pillar roadway not only depends on the advance support pressure parameters, but also arranges the drilling holes along the working face trend in the middle part of the roadway according to the site anti-scour experience, which comprehensively considers the theoretical calculation and the actual experience, so that the drilling hole arrangement is more scientific and reasonable, the pressure relief effect is further enhanced, and the stability and safety of the roadway are improved.

[0047] Further, in step S400, the hole diameter of the drilling hole is 76mm-89mm, the axial continuous coupling charging mode is used in the hole, the explosive is emulsion explosive or water-bond explosive, and the length of the grouting hole sealing section is greater than or equal to 1 / 3 of the hole depth.

[0048] The beneficial effects of the above further scheme are: the appropriate drilling hole diameter provides specific parameter standards for actual operation, facilitates construction operation and equipment selection, ensures the smooth progress and quality control of the drilling operation, and improves the reliability and consistency of the blasting operation.

[0049] The grouting hole sealing ensures the sealing quality, prevents the leakage of blasting gas, improves the blasting effect and safety, and enhances the cutting capacity of the blasting on the key layer and the pressure relief effect.

[0050] Further, in step S500, the real-time monitoring target is:

[0051] (a) Arranging a borehole stress meter on the roadway roof to monitor the plastic zone expansion range, the broken zone expansion to within 5m from the roadway side, and the stress peak shifting to a position ≥12m deep in the ore body;

[0052] (b) Continuously observing by using a microseismic monitoring system, and requiring that the energy release rate ≤10 3 J;

[0053] (c) The support pressure monitoring system records the periodic pressure step distance in real time, and the step distance shortening amplitude ≥5%.

[0054] The beneficial effects of the further scheme are: combining the borehole stress meter, the microseismic monitoring system and the support pressure monitoring system and other monitoring means, the key parameters such as stress, microseismic and support pressure of the working face after blasting are monitored in real time, the evolution law of the stress and energy of the working face after the roof blasting can be comprehensively and accurately obtained, and timely and reliable data support is provided for the subsequent optimization design of the borehole layout distance.

[0055] Further, in step S303:

[0056] The recovery side borehole arrangement of the entity pillar roadway needs to meet:

[0057] The borehole spacing is related to the working face advancing speed v, when v>5m / d, the spacing is adjusted to 10m.

[0058] The beneficial effects of the further scheme are: the dynamic adjustment mode can better adapt to the stress change in the working face advancing process, ensure that blasting pressure relief can be timely and effectively performed under different advancing speeds, improve the timeliness and effectiveness of pressure relief, and ensure the stability of the roadway in the rapid advancing process.

[0059] Further, after step S500, it further includes:

[0060] S601. The anchor net cable and the retractable U-shaped steel are jointly supported along the empty roadway, and the anchor cable pretightening force is ≥200kN;

[0061] S602. The floor is additionally provided with a φ153mm pressure relief hole, the inclination angle of the pressure relief hole is-45°, the pressure relief hole depth is 8m~10m, and the pressure relief hole spacing is 3m~5m.

[0062] The beneficial effects of the further scheme are: the support can effectively improve the support strength and stability of the roadway, enhance the deformation resistance of the roadway, provide more reliable support guarantee for the roadway after blasting pressure relief, and reduce the risk of roadway collapse. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 The step flow chart of a specific embodiment of the present application;

[0064] Figure 2 A plan view of a borehole arrangement for an embodiment of the present invention;

[0065] Figure 3 A plan view of a borehole arrangement for a working face inclination for an embodiment of the present invention;

[0066] Figure 4 A plan view of a borehole arrangement for a gob-side entry along a gob-side inclination for an embodiment of the present invention;

[0067] Figure 5 A sectional view of a borehole arrangement for a solid pillar entry along a solid pillar inclination for an embodiment of the present invention;

[0068] Figure 6 A sectional view of a borehole arrangement for a open-off cut along an open-off cut inclination for an embodiment of the present invention. DETAILED DESCRIPTION

[0069] The principles and features of the present invention are described below in conjunction with the accompanying drawings, in which the examples are presented only to explain the present invention and are not intended to limit the scope of the present invention.

[0070] In the description of the present invention, it should be understood that the terms "center", "length", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "inner", "outer", "peripheral side", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and therefore cannot be understood as indicating or implying that the system or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present invention.

[0071] In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0072] In the present invention, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0073] As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, a hard rock mine goaf lateral stress regulation deep hole blasting roof unloading method, comprising the following steps:

[0074] S100. According to the drill column chart obtained from the mine geological data or rock core experiment, the number of layers, thickness, lithology and physical and mechanical parameters of the rock stratum above the ore body of the working face are obtained, and the vertical distance H of the key layer from the ore body is obtained according to the previous observation and analysis of the ground subsidence and roof caving of the goaf;

[0075] S200. According to the overburden parameters obtained from the drill column chart, a numerical simulation model of the working face and one side of the goaf is established, and the

[0076] Working face advance support pressure peak position h1;

[0077] Advance support pressure influence range h2;

[0078] Goaf lateral support pressure peak position h3;

[0079] Goaf lateral support pressure influence range h4;

[0080] S300. Determine the position of blasting pressure relief at the key layer;

[0081] Specifically comprising the following steps:

[0082] S301. In front of the open-off cut, the working face length is L, every 10m, set 1 blasting hole, wherein:

[0083] Number of drill holes: N1=L / 10;

[0084] Drilling angle: α1=arctanα6; α6=H / h1;

[0085] Drilling depth: l1=H / sinα1;

[0086] S302. Along the two sides of the empty roadway, arrange outward at the working face advance support pressure peak position h1, and the arrangement range is within the open-off cut to the working face advance support pressure influence range h2;

[0087] Every 15m along the empty roadway side during excavation, and every 15m during mining, 1 drill hole is arranged on the empty roadway side, and 2 drill holes are arranged every 15m on the mining side, and the distance between the empty roadway and the goaf is l, wherein

[0088] Along the empty side:

[0089] Number of drill holes: N2= h2 / 7.5;

[0090] Drilling angle: α2=arctanα7; α7=H / l;

[0091] Drilling depth: l2=H / sinα2;

[0092] Stope side:

[0093] Drilling number: N3= h2 / 15

[0094] Drilling angle: α3=arctanα8; α8=H / h3;

[0095] Drilling depth: l3=H / sinα3;

[0096] Drilling number: N4= N3;

[0097] Drilling angle: α4=arctanα9; α9=H / h4;

[0098] Drilling depth: l4=H / sinα4;

[0099] S303. The entity pillar roadway is arranged outwardly at the position h1 of the peak value of the working face advance support pressure, the arrangement range is within the open-off cut to the working face advance support pressure influence range h2, one blasting pressure relief drilling is arranged every 15m along the working face dip at the stope side, the arrangement parameters are the same as the drilling 2 at the stope side of the gob-side entry, and meanwhile, combined with the site anti-scour experience, a drilling is arranged every 7.5m along the working face trend in the middle of the roadway, wherein,

[0100] Drilling number: N5= h2 / 7.5;

[0101] Drilling angle: α5=80°;

[0102] Drilling depth: l5=H / sinα5.

[0103] In the specific embodiment, based on the numerical simulation result, when the drilling spacing is less than 10m, the pressure relief effect is not obviously improved but the cost is significantly increased. When the drilling spacing is greater than 15m, the stress concentration area cannot be effectively covered, and therefore the spacing of 10m to 15m is preferred. And according to the site test and microseismic monitoring data, it is found that the spacing of 7.5m can effectively block the stress transmission path of the key stratum, in combination with the blasting influence radius R (obtained through test or experience formula), the drilling spacing is determined to be ≤ 2R, and the spacing of 7.5m / 10m / 15m is preferred to meet the requirement.

[0104] The drilling arrangement at the stope side of the entity pillar roadway needs to meet:

[0105] The drilling spacing is related to the working face advancing speed v, when v>5m / d, the spacing is adjusted to 10m.

[0106] S400. According to the position in step S300, a plurality of drillings are drilled into the main control layer, and explosives are filled in the drillings respectively, after sealing the drillings, the key stratum is cut off by using the blasting method.

[0107] In step S400, the borehole diameter is 76 mm ~ 89 mm, the axial continuous coupling charge mode is used in the borehole, the explosive is emulsion explosive or water-bond explosive, and the length of the grouting hole sealing section is ≥ 1 / 3 of the hole depth.

[0108] S500. Real-time monitoring of the stress and energy evolution law of the working face after roof blasting, and then optimizing the design of the drilling layout distance.

[0109] In step S500, real-time monitoring includes the following means:

[0110] (a) Drilling stress meters are arranged on the roadway roof to monitor the plastic zone expansion range. When the broken zone expands to within 5 m from the roadway side and the stress peak shifts to a position ≥ 12 m deep in the ore body, the stress peak shifts to a position ≥ 12 m deep in the ore body;

[0111] (b) Continuous observation is carried out using a microseismic monitoring system, and the energy release rate is required to be ≤ 10 3 J;

[0112] (c) The support pressure monitoring system records the periodic pressure step distance in real time, and the step distance shortening amplitude is ≥ 5%.

[0113] After step S500, it also includes:

[0114] S601. The anchor net cable and retractable U-shaped steel are used for combined support along the gob roadway, and the anchor cable pretightening force is ≥ 200 kN;

[0115] S602. φ153 mm pressure relief holes are added to the floor, the inclination angle of the pressure relief hole is -45°, the depth of the pressure relief hole is 8 m ~ 10 m, and the spacing between the pressure relief holes is 3 m ~ 5 m.

[0116] Example One

[0117] A hard rock roof coal mine, one side of the gob coal mining face faces serious stress concentration problems during the mining process, and often appears roadway deformation, rib spalling, roof falling and other phenomena, and there are safety hazards such as water inrush, rock burst and gas outburst. In order to solve this problem, it is decided to use the deep hole blasting roof breaking and pressure relief method.

[0118] Preparation: Collect detailed geological data of the mine, including the occurrence of mine coal seam, rock characteristics, etc. At the same time, carry out rock coring experiment, obtain drilling columnar chart, accurately understand the number of layers, thickness, lithology and physical and mechanical parameters of the rock layer above the mine coal seam of the working face. In addition, the observation data of the ground subsidence and roof caving in the goaf are sorted out, and the vertical distance H of the key layer from the mine coal seam is analyzed to be 30 m.

[0119] Numerical simulation model establishment and microseismic monitoring: According to the overburden parameters in the borehole column chart, the professional software was used to build the numerical simulation model of the working face and one side of the goaf. Combined with the data collected by the microseismic monitoring system installed on site, the peak position of the advanced abutment pressure h1=12 m, the influence range of the advanced abutment pressure h2=40 m, the peak position of the lateral abutment pressure of the goaf h3=8 m, and the influence range of the lateral abutment pressure of the goaf h4=15 m were determined.

[0120] Blasting pressure relief position determination: borehole arrangement in front of the open-off cut: the working face length L=100 m, in the area in front of the open-off cut, one blasting hole is set every 10 m, a total of N1=L / 10=10 boreholes. The borehole angle α1=arctan(H / h1)=arctan(30 / 12)=68°, the borehole depth l1=H / sinα1=30 / sin68°≈32.67 m.

[0121] Borehole arrangement along the sides of the roadway: along the sides of the roadway in the working face advanced abutment pressure peak position h1 outward, the range from the open-off cut to h2=40 m within. The roadway along the empty side is arranged every 15 m during the driving, and every 15 m during the mining; the mining side is arranged every 15 m. The distance between the roadway along the empty side and the goaf is l=10 m. The number of boreholes along the empty side N2=h2 / 7.5=40 / 7.5≈5.33, taking 6; the borehole angle α2=arctan(H / l)=arctan(30 / 10)=71.57°, the borehole depth l2=H / sinα2=30 / sin71.57°≈31.83 m. The number of borehole 1 on the mining side N3=h2 / 15=40 / 15≈2.67, taking 3; the borehole 1 angle α3=arctan(H / h3)=arctan(30 / 8)=73.3°, the borehole 1 depth l3=H / sinα3=30 / sin73.3°≈31.53 m. The number of borehole 2 N4=N3=3; the borehole 2 angle α4=arctan(H / h4)=arctan(30 / 15)=63.43°, the borehole 2 depth l4=H / sinα4=30 / sin63.43°≈33.54 m.

[0122] Solid coal roadway drilling arrangement: The solid coal roadway is arranged outward at the position h1 of the peak value of the working face advance support pressure, ranging from the open-off cut to within h2=40 m. A blasting pressure relief drill hole is arranged every 15 m along the working face dip on the recovery side. The arrangement parameters are the same as those of the drill hole 2 on the recovery side of the gateway along the goaf. At the same time, combined with the site anti-scour experience, a drill hole is arranged every 7.5 m along the working face trend in the middle of the gateway. The number of drill holes N5=h2 / 7.5=40 / 7.5≈5.33, taking 6; the drill hole angle α5=80°, and the drill hole depth l5=H / sinα5=30 / sin80°≈30.77 m.

[0123] The recovery side drill hole arrangement of the solid coal roadway meets: when the working face advancing speed v>5 m / d, the drill hole spacing is adjusted to 10 m, and α5=80°.

[0124] Drilling and blasting: According to the above determined position, a plurality of drill holes are drilled into the main control layer using a suitable drill, and the drill hole diameter is 80 mm. The axial continuous coupling charging method is used to fill the emulsion explosive in the drill hole, and the charging amount is determined according to the drill hole depth and diameter, and the length of the grouting hole sealing section is not less than 1 / 3 of the hole depth. After completing the charging and hole sealing, the blasting operation is carried out according to the blasting design parameters, and the key layer is cut off.

[0125] Real-time monitoring and optimization: Drill hole stress meter monitoring: Drill hole stress meters are arranged on the roof of the gateway to monitor the plastic zone expansion range in real time, and ensure that the broken zone is controlled within 5 m from the gateway side, and the stress peak value is successfully transferred to a position ≥12 m deep in the coal body.

[0126] Microseismic monitoring system observation: The microseismic monitoring system is used for continuous observation, and the electromagnetic radiation intensity is monitored in real time to ensure that its value is stable within ≤10 3 J, reflecting that the stress change of the rock stratum is in a controllable state.

[0127] Support pressure monitoring: The support pressure monitoring system records the periodic pressure step distance in real time, and it is observed that the step distance is shortened by ≥5%, indicating that the blasting pressure relief has a positive effect on the working face pressure.

[0128] According to these monitoring data, the drill hole arrangement distance is optimized and adjusted to further improve the pressure relief effect.

[0129] Support and floor pressure relief: Gateway along the goaf support: The anchor net cable and retractable U-shaped steel combined support is used in the gateway along the goaf, and the anchor cable pretightening force is strictly controlled at ≥200 kN, so as to ensure that the gateway has sufficient support strength, effectively resists the surrounding rock pressure, and guarantees the stability of the gateway.

[0130] The arrangement of the pressure relief hole of the floor: a φ153mm pressure relief hole is additionally arranged on the floor, the inclination angle of the pressure relief hole is -45°, the depth is 9m, and the interval is 4m. The pressure relief hole can effectively release the stress of the floor rock stratum, prevent deformation problems such as floor heave, and further improve the stress state of the roadway surrounding rock.

[0131] After the method is implemented, the problems such as spalling and roof fall of the working face roadway are obviously reduced, the stability of the roof is significantly improved, the safety hidden danger such as gas outburst is effectively controlled, and the working face recovery process is more safe and efficient.

[0132] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0133] The above only describes the preferred embodiments of the present application, and does not limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A hard rock mine goaf lateral stress regulation deep hole blasting roof breaking pressure relief method, characterized in that, It comprises the following steps: S100. According to the borehole column chart obtained from the mine geological data or stratum coring experiment, the number of layers, thickness, lithology and physical and mechanical parameters of the stratum above the ore body of the working face are obtained, and the vertical distance H of the key layer from the ore body is obtained according to the previous observation and analysis of the ground subsidence and roof caving of the goaf; S200. The numerical simulation model of the working face and one side of the goaf is established according to the overburden rock parameters obtained from the borehole column chart, and the microseismic monitoring data are combined to determine The position of the peak value of the advance abutment pressure h1 of the working face; The influence range h2 of the advance abutment pressure; The position of the peak value of the lateral abutment pressure h3 of the goaf; The influence range h4 of the lateral abutment pressure of the goaf; S300. The position of blasting pressure relief is determined in the key layer; S400. According to the position in step S300, a plurality of drill holes are drilled into the main control layer, and explosives are filled in the drill holes respectively, and after sealing, the key layer is cut off by using the blasting method; S500. The stress and energy evolution law of the working face after roof blasting is monitored in real time, and then the drilling arrangement distance is optimized; In the step S300, the following steps are specifically included: S301. In front of the open-off cut, the length of the working face is L, and every 10m, one blasting hole is drilled, wherein: The number of drill holes: N1=L / 10; Drilling angle: α1=arctanα6; α6=H / h1; Drilling depth: l1=H / sinα1; S302. Along the sides of the roadway, the position of the peak value of the advance abutment pressure h1 of the working face is arranged outward, and the arrangement range is within the advance abutment pressure influence range h2 of the working face from the open-off cut; Every 15m during the excavation of the roadway along the goaf, and every 15m during the mining, one drill hole is arranged on the goaf side, and every 15m on the mining side, two drill holes are arranged, and the distance of the roadway along the goaf from the goaf is l, wherein On the goaf side: The number of drill holes: N2=h2 / 7.5; Drilling angle: α2=arctanα7; α7=H / l; Drilling depth: l2=H / sinα2; On the mining side: The number of drill holes 1: N3=h2 / 15 Drilling angle 1: α3=arctanα8; α8=H / h3; Drilling depth 1: l3=H / sinα3; The number of drill holes 2: N4=N3; Drilling angle 2: α4=arctanα9; α9=H / h4; Drilling depth 2: l4=H / sinα4; S303. The roadway of the solid pillar is arranged outward at the position of the peak value of the advance abutment pressure h1 of the working face, and the arrangement range is within the advance abutment pressure influence range h2 of the working face from the open-off cut, and every 15m along the inclination of the working face on the mining side, one blasting pressure relief drill hole is arranged, and the arrangement parameters are the same as the drill hole 2 on the mining side of the roadway along the goaf, and at the same time, combined with the site anti-scour experience, every 7.5m along the strike of the working face in the middle of the roadway, a drill hole is arranged, wherein, The number of drill holes: N5=h2 / 7.5; Drilling angle: α5=80°; Drilling depth: l5=H / sinα5.

2. The deep hole blasting roof breaking and pressure relief method for regulating lateral stress of a hard rock mine goaf according to claim 1, characterized in that: In step S400, the borehole diameter is 76mm-89mm, the axial continuous coupling charging mode is used in the borehole, the explosive is emulsion explosive or water-bonded explosive, and the length of the grouting and hole sealing section is greater than or equal to 1 / 3 of the hole depth.

3. The hard rock mine goaf lateral stress regulation deep hole blasting roof breaking and pressure releasing method according to claim 1, characterized in that: In step S500, the real-time monitoring target is: (a) arranging a borehole stress meter on the roadway roof to monitor the plastic zone expansion range, the broken zone expansion to within 5m from the roadway side, and the stress peak shifting to a position greater than or equal to 12m deep in the ore body; (b) Continuous observation with a microseismic monitoring system, with a requirement that the energy release rate be <10 3 J; (c) the support pressure monitoring system records the periodic pressure step distance in real time, and the step distance shortening amplitude is greater than or equal to 5%.

4. The hard rock mine goaf lateral stress regulation deep hole blasting roof breaking and pressure releasing method according to claim 1, characterized in that, In step S303: The arrangement of the recovery side borehole of the entity pillar roadway needs to meet: The borehole spacing is related to the working face advancing speed v, when v>5m / d, the spacing is adjusted to 10m.

5. The hard rock mine goaf lateral stress regulation deep hole blasting roof breaking and pressure releasing method according to claim 1, characterized in that, After step S500, it further includes: S601. The combined support of anchor net cable and retractable U-shaped steel is used in the gob roadway, and the anchor cable pretightening force is greater than or equal to 200kN; S602. The φ153mm pressure relief hole is additionally arranged on the floor, the inclination angle of the pressure relief hole is-45°, the pressure relief hole depth is 8m-10m, and the pressure relief hole spacing is 3m-5m.

Images