A method for controlling water hazard by drilling and draining water in mine goaf to prevent water accumulation

Abstract

The present invention discloses a method for controlling water hazard of goaf area water accumulation by drilling and draining to prevent water from being blocked. According to geological conditions, the occurrence of overburden aquifers and aquicludes, the development of overburden fissures caused by mining, and the exploration results of electrical methods and geophysical prospecting, water accumulation in the goaf is controlled through dynamic supply sources and static water storage spaces, thus forming a systematic and complete method for controlling water hazard in goaf area. A specific method for controlling water hazard in goaf area water accumulation is provided, which comprises three parts: isolation scheme design, blocking water bursting points and water pressure reduction, thereby blocking the replenishment effect of dynamic supply sources on water accumulation in goaf area. Water pressure reduction is achieved by draining the aquifers in the top and bottom plates of the goaf through waterproof holes in the top plate and waterproof holes in the bottom plate, thereby reducing hydraulic pressure and thus reducing water filling volume and water bursting risk. The technical problems of heavy workload and safety hazards caused by untimely water drainage in goaf water drainage technology are solved.

Description

Technical Field

[0001] The invention belongs to the field of coal mine water hazard prevention and control, and relates to a water hazard control method, in particular to a water hazard control method for preventing water accumulation and draining water through drilling in a mine goaf area. Background Art

[0002] In recent years, as coal resources have shifted from shallow to mid-level development to deep to ultra-deep mining, the number of mined seams at the top of coal seams has steadily increased, and the overburden structure and geological structure have become increasingly complex. Repeated mining and the mining of multiple layers and groups of coal seams have led to water accumulation within the goaf at the top of the coal seams. When mining of the lower coal group disturbs the seams, the mining-induced fissures connect to the water in the upper goaf. The accumulated water in the goaf then flows through the mining fissures, causing underground water inrush accidents. Water in the old goaf caused by water accumulation in coal mine mining areas is characterized by huge instantaneous water inrush, severe damage, and corrosiveness, and has long been one of the main types of water hazards that threaten coal mine production safety.

[0003] Before the working face is normally mined, draining the water in the goaf by drilling holes on the ground is an effective measure to control water hazards in the goaf. Since the water in the goaf is highly mineralized and rich in rock debris, during the goaf water drainage construction process, the rock debris can easily flow through the drainage boreholes with the drainage water, thereby accumulating inside the drainage boreholes and blocking the drainage boreholes, resulting in a reduction in drainage volume, which in turn affects the drainage work. The existing goaf drainage technology uses repeated drilling and sweeping methods to clear the drainage boreholes. Not only does it increase the drilling workload and cause delays in the drainage period, but it also causes the water in the goaf to not be drained in time, which in turn increases the risk of water inrush from old goaf water hazards, seriously threatening underground production safety.

[0004] Based on existing mine water drainage technology, it is urgent to develop an efficient, rapid, and long-lasting method for draining water from goafs. To this end, the present invention proposes a method for draining water from goafs by preventing water from blocking the boreholes. The invention also designs an anti-blocking drilling device for draining water from goafs. This device aims to eliminate impurities such as rock debris from clogging the drainage boreholes during the drainage process, thereby affecting the drainage process and improving the utilization rate of the water discharged through the boreholes. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for controlling water hazards in mine goaf areas by drilling and draining water to prevent water accumulation and blockage, so as to solve the technical problems of large workload and safety hazards caused by untimely drainage in goaf drainage technology.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for preventing water from accumulating in a mine goaf by drilling and draining water, specifically comprising the following steps:

[0008] Step 1: Determine the dynamic recharge source and static water storage space of water accumulation in the goaf based on geological conditions, the occurrence of overburden aquifers and aquicludes, the development of overburden fractures caused by mining, and the results of electrical and geophysical exploration.

[0009] Step 2: Based on the electrical and geophysical exploration results of step 1, determine the water level, layer, and head in the goaf, and estimate the amount of water in the goaf. ;

[0010] The amount of water accumulated in the goaf The estimated formula is as follows:

[0011]

[0012] Where:

[0013] M Indicates the mining thickness of the coal seam, m;

[0014] L Indicates the strike length of the mining face, m;

[0015] h Indicates the water head height in the goaf, m;

[0016] α represents the coal seam inclination, º;

[0017] K Indicates the water filling coefficient of the goaf, ranging from 0.3 to 0.5.

[0018] Step 3: Determine and implement a flood control plan for waterlogging in the goaf;

[0019] The water hazard control scheme for water accumulation in the goaf includes an isolation scheme, a water inrush point blocking scheme, and a water pressure reduction scheme;

[0020] The isolation scheme is to block the dynamic water supply source of the goaf, specifically including cutting off the surface hydraulic connection, cutting off the water supply source and leaving coal rock pillars for zoning blocking;

[0021] The solution for blocking the water inrush point is to block the dynamic recharge source of the goaf determined in step 1, specifically by grouting to block the recharge channel of the strong aquifer and the strong recharge water source to the goaf, so that an aquiclude is formed between the strong aquifer and the strong recharge water source and the goaf;

[0022] The water pressure reduction scheme is to reduce the water pressure of the top plate and bottom plate through the top plate through the water holes and the bottom plate through the water holes;

[0023] Step 4: Use drilling or natural electric field method to detect water accumulation in the goaf and judge the blocking effect of the water hazard control plan in step 3;

[0024] The method for drilling and detecting water accumulation in goaf areas specifically includes the following contents:

[0025] The change in the borehole water pressure index value in the drainage monitoring system installed in the mine is used to judge. If the borehole water pressure index value decreases and remains unchanged, it proves that the treatment effect is good, and the process proceeds to step five. If the borehole water pressure index value remains constant, it indicates that the dynamic supply source of water accumulation in the goaf is not completely blocked, and the process returns to step three.

[0026] The monitoring parameters of the drainage water monitoring system also include the water output of the borehole, specifically including the water quality and water output of the borehole;

[0027] Step 5: Determine the drainage plan for the water in the goaf;

[0028] The drainage plan for the goaf water accumulation includes determining the drainage capacity, the maximum drainage volume of a single hole and the number of holes drilled;

[0029] The drainage capacity is greater than the maximum amount of water that should be discharged from the goaf. Q 放max The calculation formula is as follows:

[0030]

[0031] in:

[0032] Q 放max Indicates the maximum amount of water that should be released from the goaf, m 3 / s;

[0033] a Indicates the strike length of the goaf;

[0034] b Indicates the oblique length of the goaf;

[0035] H Indicates the distance between the drainage water level in the goaf and the rock layer at the bottom of the goaf;

[0036] t Indicates the allowed drainage time, s;

[0037] Q 补 Indicates dynamic water filling volume, m 3 / s;

[0038] The calculation formula for the maximum drainage capacity of a single hole is as follows:

[0039]

[0040] in:

[0041] Indicates the maximum drainage volume of a single hole, m 3 / s;

[0042] c Indicates the flow coefficient, generally ranging from 0.6 to 0.62;

[0043] S 钻 Indicates the cross-sectional area of ​​the borehole, m 2 ;

[0044] g represents the acceleration due to gravity, which is 9.8 m / s 2 ;

[0045] Indicates 0.4~0.5 times the water head height at the borehole outlet, m;

[0046] The calculation formula for the number of drilling holes is as follows:

[0047]

[0048] Where:

[0049] N The number of boreholes required to drain water from the goaf;

[0050] Q 放max Indicates the maximum amount of water that should be released from the goaf;

[0051] g represents the acceleration due to gravity, which is 9.8 m / s 2 ;

[0052] Step six: drain water according to the drainage plan for the goaf determined in step five.

[0053] The present invention also includes the following technical features:

[0054] The drainage scheme for the goaf water determined in step 5 is carried out to drain water, specifically comprising the following steps:

[0055] Step 6.1, determining the number n of filter tubes of the anti-blocking drilling device, and then determining the anti-blocking drilling device;

[0056] L = H / sin α

[0057] n=L / l+ 1

[0058] in:

[0059] H Indicates the distance between the drainage water level in the goaf and the rock layer at the bottom of the goaf;

[0060] α is the angle between the rock layer at the bottom of the goaf and the filter pipe;

[0061] L is the total length of the filter tube;

[0062] l is the filter tube length, ranging from 1.5 to 3 m;

[0063] Step 6.2, deploying the anti-blocking drilling device into the borehole through the drill rod;

[0064] After the drilling project is completed and the bottom plate of the goaf is drilled, a water drainage and anti-blocking drilling device is installed in the borehole, a thruster is installed in front of the drill rod, and the drill is re-drilled. The water drainage and anti-blocking drilling device is pushed into the goaf along the drilling advancement direction;

[0065] When the top of the topmost filter pipe exceeds the water level in the goaf, stop advancing, lift the drill rod, and pull the drill rod out of the hole. At this time, the locking wing of the anti-retraction structure is inserted into the wall of the hole, and the locking wing cannot be reversely compressed to close to the filter pipe. The water drainage and anti-blocking drilling device is completely fixed.

[0066] Step 6.3, using an anti-blocking drilling device to drain water;

[0067] The accumulated water in the goaf flows into the drill hole through the filter holes of the filter tube. The accumulated water in the goaf passes through the filter holes smoothly and flows out, filtering out the rock debris and impurities in the accumulated water in the goaf until the goaf water drainage project is completed.

[0068] The anti-blocking drilling device includes a plurality of fixedly connected filter tubes, each of which is provided with an anti-retraction structure on the top, and a propeller is fixedly installed on the bottom filter tube, one end of which is connected to the filter tube through a propeller head, and the other end of which is provided with a thread;

[0069] The anti-retreat structure includes a fixing plate fixed on the outer wall of the filter tube, a welding ridge is fixedly provided in the middle of the fixing plate, and a symmetrically distributed clamping wing is rotatably provided on the top of the fixing plate. One end of a spring is provided in the axial middle part of each clamping wing, and the other end of the spring is fixedly provided on one side of the welding ridge; the angle between the filter tube and the clamping wing is less than 90°.

[0070] A plurality of filter holes are evenly arranged on the filter tube.

[0071] The filter tube is a welded tube or a geological tube with a diameter less than 89 mm and a length of 1.5 to 3 m.

[0072] Compared with the prior art, the present invention has the following beneficial technical effects:

[0073] (I) The present invention controls water accumulation in goafs through dynamic supply sources and static water storage spaces, thereby forming a systematic and complete method for controlling water hazards in goafs. The goaf water hazard control scheme fully considers the mine drainage capacity and the mine water tank capacity to control the water discharge flow rate for design. A specific goaf water hazard control scheme consisting of three parts, namely, isolation scheme design, blocking water burst points, and water pressure reduction, is provided to block the dynamic supply source from replenishing water in goafs. The water pressure reduction is achieved by reducing the water-bearing layers of the goaf top and bottom plates through the waterproof holes in the top plate and the waterproof holes in the bottom plate, thereby reducing the hydraulic pressure and thus reducing the water filling volume and the risk of water bursts. The technical problems of heavy workload and safety hazards caused by untimely water drainage in goaf drainage technology are solved.

[0074] (II) The filter tube in the anti-blocking drilling device of the present invention has low production cost and simple construction process, which avoids increasing the difficulty and construction cost of the water drainage technology in the goaf. Even if the filter tube is not recovered in the later stage, it will not cause technical problems such as blockage or closure of the drilling hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 Ideas on water hazard control by drilling and draining water to prevent water accumulation in mine goaf areas;

[0076] Figure 2 This is a structural diagram of a drilling device for draining water and preventing blockage in goaf areas;

[0077] Figure 3 It is a schematic diagram of the propeller structure;

[0078] Figure 4 1. It is a schematic diagram of the structure of the anti-retreat device;

[0079] Figure 5 This is a schematic diagram of the filter pipe inside the goaf where water accumulates.

[0080] The meanings of the numbers in the figure are: 1-filter tube, 2-anti-recoil structure, 3-propeller, 4-propeller head, 5-thread, 6-bottom stratum of goaf; 7-water accumulation in goaf;

[0081] 201-fixed plate, 202-welding ridge, 203-clamping wing, 204-spring.

[0082] The specific contents of the present invention are further explained in detail below with reference to the embodiments. DETAILED DESCRIPTION

[0083] Since the geometric characteristics of the goaf are extremely irregular, the rock layer at the bottom of the goaf is selected at the lowest point around the drainage borehole at the bottom of the goaf to ensure that the filter pipe can penetrate the water inside the goaf.

[0084] It should be noted that, unless otherwise specified, all components in the present invention are components known in the art.

[0085] The present invention provides a method for controlling water hazard by drilling and draining water in a mine goaf to prevent water accumulation, which specifically includes the following steps:

[0086] A method for preventing water from accumulating in a mine goaf by drilling and draining water, specifically comprising the following steps:

[0087] Step 1: Determine the dynamic recharge source and static water storage space of water accumulation in the goaf based on geological conditions, the occurrence of overburden aquifers and aquicludes, the development of overburden fractures caused by mining, and the results of electrical and geophysical exploration.

[0088] Step 2: Based on the electrical and geophysical exploration results of step 1, determine the water level, layer, and head in the goaf, and estimate the amount of water in the goaf. ;

[0089] Water accumulation in goaf The estimated formula is as follows:

[0090]

[0091] Where:

[0092] M Indicates the mining thickness of the coal seam, m;

[0093] L Indicates the strike length of the mining face, m;

[0094] h Indicates the water head height in the goaf, m;

[0095] α represents the coal seam inclination, º;

[0096] K Indicates the water filling coefficient of the goaf, ranging from 0.3 to 0.5.

[0097] Step 3: Determine and implement a flood control plan for waterlogging in the goaf;

[0098] The water hazard control plan for water accumulation in the goaf includes isolation plan, blocking water inrush point plan and water pressure reduction plan;

[0099] The isolation plan is to block the dynamic water supply source of the goaf, specifically including cutting off the surface hydraulic connection, cutting off the water supply source and leaving coal rock pillars for zoning blocking;

[0100] In the above scheme, the dynamic recharge source in the first step is blocked as much as possible from recharging the water in the goaf;

[0101] The solution for blocking the water inrush point is to block the dynamic recharge source of the goaf determined in step 1. Specifically, the recharge channel of the strong aquifer and the strong recharge water source to the goaf is blocked by grouting, so that an aquiclude is formed between the strong aquifer and the strong recharge water source and the goaf.

[0102] The water pressure reduction scheme is to reduce the water pressure of the top and bottom plates through the top plate through-layer drainage holes and the bottom plate through-layer drainage holes respectively.

[0103] In the above scheme, the hydraulic pressure is reduced, thereby reducing the water filling volume and the risk of water inrush.

[0104] Step 4: Use drilling or natural electric field method to detect water accumulation in the goaf and judge the blocking effect of the water hazard control plan in step 3;

[0105] The methods for drilling to detect water accumulation in goaf areas include the following:

[0106] The change in the borehole water pressure index value in the drainage monitoring system installed in the mine is used to judge. If the borehole water pressure index value decreases and remains unchanged, it proves that the treatment effect is good, and the process proceeds to step five. If the borehole water pressure index value remains constant, it indicates that the dynamic supply source of water accumulation in the goaf is not completely blocked, and the process returns to step three.

[0107] The monitoring parameters of the drainage water volume monitoring system also include the borehole water output, specifically including the borehole water quality and borehole water output;

[0108] In the above technical solution, the drainage water volume monitoring system is a conventional device used for underground water level monitoring, such as a flow valve.

[0109] Step 5: Determine the drainage plan for the water in the goaf;

[0110] The drainage plan for water accumulation in the goaf includes determining the drainage capacity, the maximum drainage volume of a single hole and the number of holes to be drilled;

[0111] The drainage capacity is greater than the maximum amount of water that should be released in the goaf. Q 放max The calculation formula is as follows:

[0112]

[0113] in:

[0114] Q 放max Indicates the maximum amount of water that should be released from the goaf, m 3 / s;

[0115] a Indicates the strike length of the goaf;

[0116] b Indicates the oblique length of the goaf;

[0117] H Indicates the distance between the drainage water level in the goaf and the rock layer at the bottom of the goaf;

[0118] t Indicates the allowed drainage time, s;

[0119] Q 补 Indicates dynamic water filling volume, m 3 / s;

[0120] The calculation formula for the maximum drainage volume of a single hole is as follows:

[0121]

[0122] in:

[0123] Indicates the maximum drainage volume of a single hole, m 3 / s;

[0124] c Indicates the flow coefficient, generally ranging from 0.6 to 0.62;

[0125] S 钻 Indicates the cross-sectional area of ​​the borehole, m 2 ;

[0126] g represents the acceleration due to gravity, which is 9.8 m / s 2 ;

[0127] Indicates 0.4~0.5 times the water head height at the borehole outlet, m;

[0128] The calculation formula for the number of drill holes is as follows:

[0129]

[0130] Where:

[0131] N The number of boreholes required to drain water from the goaf;

[0132] Q 放max Indicates the maximum amount of water that should be released from the goaf;

[0133] g represents the acceleration due to gravity, which is 9.8 m / s 2 ;

[0134] Step six: drain water according to the drainage plan for the goaf determined in step five.

[0135] In the above technical scheme, the water accumulation in the goaf is controlled through dynamic supply sources and static water storage spaces, forming a systematic and complete method for goaf water hazard control; the goaf water hazard control scheme fully considers the mine drainage capacity and the mine water tank capacity to control the water discharge flow rate for design; a specific goaf water hazard control scheme consisting of three parts is set up, including isolation scheme design, blocking water inrush points and water pressure reduction, which blocks the replenishment effect of dynamic supply sources on water accumulation in the goaf; water pressure reduction is to reduce the water-bearing layers on the top and bottom plates of the goaf through the roof through-layer waterproof holes and the bottom plate through-layer waterproof holes to reduce the hydraulic pressure, thereby reducing the water filling volume and the risk of water inrush; it solves the technical problems of large workload in goaf water drainage technology and safety hazards caused by untimely drainage.

[0136] Specifically, drainage is carried out according to the drainage plan for the goaf water determined in step 5, which specifically includes the following steps:

[0137] Step 6.1, determining the number n of filter tubes of the anti-blocking drilling device, and then determining the anti-blocking drilling device;

[0138] L = H / sin α

[0139] n=L / l+ 1

[0140] in:

[0141] H Indicates the distance between the drainage water level in the goaf and the rock layer at the bottom of the goaf;

[0142] α is the angle between the rock layer at the bottom of the goaf and the filter pipe;

[0143] L is the total length of the filter tube;

[0144] l is the filter tube length, ranging from 1.5 to 3 m;

[0145] Step 6.2, deploying the anti-blocking drilling device into the borehole through the drill rod;

[0146] After the drilling project is completed and the bottom plate of the goaf is drilled, a water drainage and anti-blocking drilling device is installed in the borehole, a thruster is installed in front of the drill rod, and the drill is re-drilled. The water drainage and anti-blocking drilling device is pushed into the goaf along the drilling advancement direction;

[0147] When the top of the topmost filter pipe exceeds the water level in the goaf, stop advancing, lift the drill rod, and pull the drill rod out of the hole. At this time, the locking wing of the anti-retraction structure is inserted into the wall of the hole, and the locking wing cannot be reversely compressed to close to the filter pipe. The water drainage and anti-blocking drilling device is completely fixed.

[0148] Step 6.3, using an anti-blocking drilling device to drain water;

[0149] The accumulated water in the goaf flows into the drill hole through the filter holes of the filter tube. The accumulated water in the goaf passes through the filter holes smoothly and flows out, filtering out the rock debris and impurities in the accumulated water in the goaf until the goaf water drainage project is completed.

[0150] In the above technical method, during the drainage process of the goaf, under the action of the dynamic water flow of the drainage water, the goaf drainage and anti-blocking drilling device is subjected to a downward force. With the support of the anti-retreat structure wing, the goaf drainage device is fixed in place, preventing rock chips and impurities from entering the borehole wall and blocking the drainage borehole, thereby achieving continuous drainage of the drainage borehole.

[0151] The anti-retreat structure 4 can be compressed along the advancing direction. During the process of the goaf water drainage and anti-blocking drilling device advancing toward the goaf, the angle between the anti-retreat structure 4 and the filter tube 1 is <90º, and the anti-retreat structure 4 is compressed toward the filter tube side by the extrusion stress. When the goaf water drainage and anti-blocking drilling device is advanced to the designed position determined in step 1, the anti-retreat structure 4 is supported by the directional force of the borehole wall under the action of its own gravity, and the anti-retreat structure 4 cannot shift, thereby preventing the goaf water drainage and anti-blocking drilling device from shifting.

[0152] Specifically, the anti-blocking drilling device includes a plurality of fixedly connected filter tubes 1. The top of each filter tube 1 is provided with an anti-retraction structure 2. A propeller 3 is fixedly installed on the bottom filter tube 1. One end of the propeller 3 is connected to the filter tube 1 through a propeller head 4. The other end of the propeller 3 is provided with a thread 5.

[0153] The anti-retraction structure 2 includes a fixing plate 201 fixed to the outer wall of the filter tube 1. A welded ridge 202 is fixedly provided in the middle of the fixing plate. The top of the fixing plate 201 is rotatably provided with symmetrically distributed locking wings 203. One end of a spring 204 is provided in the axial middle of each locking wing 203, and the other end of the spring 204 is fixedly provided on one side of the welded ridge 202. The angle between the filter tube 1 and the locking wings 203 is less than 90°.

[0154] Specifically, a plurality of filter holes are evenly arranged on the filter tube.

[0155] Preferably, the filter holes on the filter tube are 10 mm.

[0156] Specifically, the filter tube is a welded tube or a geological tube with a diameter less than 89 mm and a length of 1.5 to 3 m.

Claims

1. A method for preventing water from clogging up the goaf of a mine by drilling and draining water, characterized in that: The specific steps include: Step 1: Determine the dynamic recharge source and static water storage space of water accumulation in the goaf based on geological conditions, the occurrence of overburden aquifers and aquicludes, the development of overburden fractures caused by mining, and the results of electrical and geophysical exploration. Step 2: Based on the electrical and geophysical exploration results of step 1, determine the water level, layer, and head in the goaf, and estimate the amount of water in the goaf. ; The amount of water accumulated in the goaf The estimated formula is as follows: Where: M Indicates the mining thickness of the coal seam, m; L Indicates the strike length of the mining face, m; h Indicates the water head height in the goaf, m; α represents the coal seam inclination, °; K Indicates the water filling coefficient of the goaf, ranging from 0.3 to 0.5; Step 3: Determine and implement a flood control plan for waterlogging in the goaf; The water hazard control scheme for water accumulation in the goaf includes an isolation scheme, a water inrush point blocking scheme, and a water pressure reduction scheme; The isolation scheme is to block the dynamic water supply source of the goaf, specifically including cutting off the surface hydraulic connection, cutting off the water supply source and leaving coal rock pillars for zoning blocking; The solution for blocking the water inrush point is to block the dynamic recharge source of the goaf determined in step 1, specifically by grouting to block the recharge channel of the strong aquifer and the strong recharge water source to the goaf, so that an aquiclude is formed between the strong aquifer and the strong recharge water source and the goaf; The water pressure reduction scheme is to reduce the water pressure of the top plate and bottom plate through the top plate through the water holes and the bottom plate through the water holes; Step 4: Use drilling or natural electric field method to detect water accumulation in the goaf and judge the blocking effect of the water hazard control plan in step 3; The method for drilling and detecting water accumulation in goaf areas specifically includes the following contents: The change in the borehole water pressure index value in the drainage monitoring system installed in the mine is used to judge. If the borehole water pressure index value decreases and remains unchanged, it proves that the treatment effect is good, and the process proceeds to step five. If the borehole water pressure index value remains constant, it indicates that the dynamic supply source of water accumulation in the goaf is not completely blocked, and the process returns to step three. The monitoring parameters of the drainage water monitoring system also include the water output of the borehole, specifically including the water quality and water output of the borehole; Step 5: Determine the drainage plan for the water in the goaf; The drainage plan for the goaf water accumulation includes determining the drainage capacity, the maximum drainage volume of a single hole and the number of holes drilled; The drainage capacity is greater than the maximum amount of water that should be discharged from the goaf. Q 放max The calculation formula is as follows: in: Q 放max Indicates the maximum amount of water that should be released from the goaf, m 3 / s; a Indicates the strike length of the goaf; b Indicates the oblique length of the goaf; H Indicates the distance between the drainage water level in the goaf and the rock layer at the bottom of the goaf; t Indicates the allowed drainage time, s; Q 补 Indicates dynamic water filling volume, m 3 / s; The calculation formula for the maximum drainage capacity of a single hole is as follows: in: Indicates the maximum drainage volume of a single hole, m 3 / s; c Indicates the flow coefficient, generally ranging from 0.6 to 0.62; S 钻 Indicates the cross-sectional area of ​​the borehole, m 2 ; g represents the acceleration due to gravity, which is 9.8 m / s 2 ; Indicates 0.4~0.5 times the water head height at the borehole outlet, m; The calculation formula for the number of drilling holes is as follows: Where: N The number of boreholes required to drain water from the goaf; Q 放max Indicates the maximum amount of water that should be released from the goaf; g represents the acceleration due to gravity, which is 9.8 m / s 2 ; Step 6: Drain water according to the drainage plan for the goaf determined in step 5; The anti-blocking drilling device comprises a plurality of fixedly connected filter tubes (1), the top of each filter tube (1) is provided with an anti-retraction structure (2), a propeller (3) is fixedly mounted on the bottom filter tube (1), one end of the propeller (3) is connected to the filter tube (1) via a propeller head (4), and the other end of the propeller (3) is provided with a thread (5); The anti-retreat structure (2) comprises a fixing plate (201) fixed on an outer wall of the filter tube (1), a welding ridge (202) fixedly provided in the middle of the fixing plate, symmetrically distributed locking wings (203) rotatably provided on the top of the fixing plate (201), one end of a spring (204) provided in the axial middle of each locking wing (203), and the other end of the spring (204) fixedly provided on one side of the welding ridge (202); the angle between the filter tube (1) and the locking wing (203) is less than 90°.

2. The method for preventing water from clogging up the mine goaf by drilling and draining water as claimed in claim 1, characterized in that: The drainage scheme for the goaf water determined in step 5 specifically includes the following steps: Step 6.1, determining the number n of filter tubes of the anti-blocking drilling device, and then determining the anti-blocking drilling device; L = H / sin α n=L / l+ 1 in: H Indicates the distance between the drainage water level in the goaf and the rock layer at the bottom of the goaf; α is the angle between the rock layer at the bottom of the goaf and the filter pipe; L is the total length of the filter tube; l is the filter tube length, ranging from 1.5 to 3 m; Step 6.2, deploying the anti-blocking drilling device into the borehole through the drill rod; After the drilling project is completed and the bottom plate of the goaf is drilled, a water drainage and anti-blocking drilling device is installed in the borehole, a thruster is installed in front of the drill rod, and the drill is re-drilled. The water drainage and anti-blocking drilling device is pushed into the goaf along the drilling advancement direction; When the top of the topmost filter pipe exceeds the water level in the goaf, stop advancing, lift the drill rod, and pull the drill rod out of the hole. At this time, the locking wing of the anti-retraction structure is inserted into the wall of the hole, and the locking wing cannot be reversely compressed to close to the filter pipe. The water drainage and anti-blocking drilling device is completely fixed. Step 6.3, using an anti-blocking drilling device to drain water; The accumulated water in the goaf flows into the drill hole through the filter holes of the filter tube. The accumulated water in the goaf passes through the filter holes smoothly and flows out, filtering out the rock debris and impurities in the accumulated water in the goaf until the goaf water drainage project is completed.

3. The method for preventing water from clogging up the mine goaf by drilling and draining water as claimed in claim 1, characterized in that: The filter tube (1) is evenly provided with a plurality of filter holes.

4. The method for controlling water hazard by drilling and draining water to prevent water accumulation in the goaf of a mine as described in claim 1, wherein the filter tube (1) is a welded tube or a geological tube with a diameter less than 89 mm and a length of 1.5 to 3 m.

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