Roadway overburden water area pre-splitting diversion and drainage method

Abstract

The application discloses a kind of roadway overburden water area pre-splitting diversion drainage methods, it is related to coal mine advanced exploration water drainage technical field.The method includes the following steps: S1, determine water area, if no exception, continue to excavate, there is exception, handle;S2, design hydraulic fracturing borehole parameter;S3, construction hydraulic fracturing borehole;S4, connect water injection system, verify hole sealing effect, carry out fracturing, record pressure data, continue to inject water and expand crack after crack, monitor outlet data, confirm crack communication confined water area;S5, install hole pipe sealing and drainage;S6, construction borehole on both sides, form diversion crack net;S7, design and construction water drainage borehole group, connect drainage system;S8, real-time monitoring drainage condition, complete and remove drainage system.The application solves the problem of water inrush of water drainage hole in confined water area, improves the safety and efficiency of water drainage in confined water area and roadway excavation, and realizes safe and efficient production of mine.

Description

Technical Field

[0001] This invention relates to the field of advanced water exploration and drainage technology in coal mines, specifically to a method for pre-fracture diversion and drainage of confined aquifers overlying roadways. Background Technology

[0002] As the depth of coal mining increases, roadways are prone to encountering confined water zones during excavation. Traditional drilling methods often involve directly drilling into these confined water zones. However, if the water pressure is too high, the water flow will directly gush out of the borehole, causing a water inrush accident that damages equipment, personnel, and roadway construction.

[0003] Currently, the solutions to the problem of water inrush during drilling in confined water areas mainly focus on drilling equipment, sealing devices, and processes. For example, Chinese Patent No. CN220566053U discloses a downhole water exploration and drainage anti-blowout device that can prevent water leakage by eliminating the gap between the drill rod and the drill rod during high-pressure water injection without hindering the rotation of the drill rod during drilling; Chinese Patent No. CN109488370A discloses a construction method for drilling holes for water exploration and drainage in limestone wells. By improving the casing sealing and grouting process, a single grouting can meet the pressure holding requirements, improving construction efficiency and safety; Chinese Patent No. CN210858807U discloses a pressure reducing device for high-pressure water drilling in coal mines. It uses an angled orifice pipe to achieve pressure relief and diversion of high-pressure water, thereby reducing water pressure and preventing high-pressure water from directly spraying out from the borehole wall; Chinese Patent No. CN111155929A discloses a high-water-pressure top-water directional drilling tool and drilling method for water prevention holes in coal mines. It ensures that the bottom-hole power drilling tool works normally and the output torque parameters do not change significantly under the condition of a large amount of water flowing into the hole from the high-water-pressure formation. While the aforementioned patents have solved the problem of water inrush in the exploration and drainage holes of confined water areas to some extent, the method of directly drilling into the confined water area for exploration and drainage remains unchanged. Furthermore, due to differences in pressure, drilling conditions, and personnel technical levels in different confined water areas of various mines, the applicability and safety of the aforementioned patents are still insufficient. Summary of the Invention

[0004] To address the aforementioned problems, this invention discloses a pre-fracture diversion and drainage method for confined aquifers overlying roadways. This method enables precise detection of confined aquifers overlying roadways, and the formation of a fracture network by hydraulic fracturing boreholes at the boundary of the confined aquifers to connect the confined aquifers and divert and depressurize them. Then, in conjunction with drainage boreholes, the method utilizes a drainage system to safely and efficiently detect and release water from the confined aquifers overlying roadways during tunnel excavation, thereby improving tunnel excavation efficiency.

[0005] A pre-fracturing and drainage method for confined aquifer overlying roadway, proposed according to the present invention, includes the following steps:

[0006] S1. Use the transient electromagnetic method to detect the water-bearing pressure area at the ultra-front end of the roadway heading. If the measurement results show no water-rich abnormal area, continue tunneling. If there is a water-rich abnormal area, determine the scope of the water-bearing pressure area according to the measurement results. Establish a spatial rectangular coordinate system with the heading face as point O. The forward direction along the tunneling direction is the X-axis, perpendicular to the tunneling direction is the Y-axis, and upward along the roof is the Z-axis. x1, x2, y1, y2, z1, z2 are the boundary coordinate values of the water-bearing pressure area detected by the transient electromagnetic method, where x1 < x2, y1 < y2, z1 < z2. The scope of the water-bearing pressure area is (x1~x2, y1~y2, z1~z2). When x1 is less than 30 m, continue tunneling the roadway. When x1 is not less than 30 m, perform steps S2 - S8 for water drainage operation;

[0007] S2. Design the parameters of the hydraulic fracturing borehole group according to the scope of the water-bearing pressure area and the specific geological conditions of the tunneling roadway;

[0008] S3. Use a drilling rig to construct the middle hydraulic fracturing boreholes according to the design parameters, and slot in the hydraulic fracturing boreholes;

[0009] S4. After the hydraulic fracturing boreholes are drilled, flush them with static water and install and connect the packer. After the packer is installed, conduct a pressure-holding test to verify the sealing effect. After determining that the packer can work properly, connect the hydraulic fracturing equipment for fracturing until the fracturing cracks connect to the water-bearing pressure area, and water flows into the hydraulic fracturing boreholes through the cracks, then stop fracturing;

[0010] S5. Withdraw the hydraulic fracturing equipment, install a hole pipe to seal the hydraulic fracturing boreholes, install a drainage system for water drainage, and record the data of the drainage system flowmeter;

[0011] S6. Repeat S3 - S5 to construct the hydraulic fracturing boreholes on both sides of the middle hydraulic fracturing boreholes to form a diversion crack network;

[0012] S7. Estimate the water volume according to the scope of the water-bearing pressure area, and record the data of the drainage system flowmeter. When the drainage volume reaches 1 / 5 of the estimated water volume, design and construct a water drainage borehole group to directly connect to the water-bearing pressure area. After the construction is completed, connect the drainage system for water drainage;

[0013] S8. Real-time monitor the water inrush pressure and water inrush volume through the pressure gauge at the water drainage borehole and the drainage system flowmeter, evaluate the water drainage effect. If data anomalies occur, stop the water drainage operation in time and plug the boreholes. After the water drainage is completed, remove the drainage system and seal the boreholes.

[0014] Preferably, in S1, when using the transient electromagnetic method to detect the pressurized water zone at the leading edge of the roadway face, the transmitting coil and the receiving coil are arranged in parallel and arranged in a fan-shaped multi-angle configuration for the roadway roof. The angle between the coil directly in front and the roadway floor is 30° and 60°, the angle between the side roof position and the roadway floor is 45°, and the angle between coils in different directions is 60°.

[0015] Preferably, in S2, the hydraulic fracturing borehole parameters include the location, diameter, and spacing of the hydraulic fracturing boreholes; the starting point of the hydraulic fracturing boreholes is set at 15m from the face of the tunneling face, facing the boundary of the confined water zone, with a total of three, and the diameter of the hydraulic fracturing boreholes is 65mm; the three hydraulic fracturing boreholes are arranged in the Y direction, and the distance between the starting points of adjacent hydraulic fracturing boreholes is 1.5m.

[0016] Preferably, in S2, the hydraulic fracturing borehole parameters also include the drilling inclination angle, borehole length, and the angle between the two hydraulic fracturing boreholes and the roadway cross-section; the pre-fracturing layer for hydraulic fracturing is the middle of the confined aquifer zone, i.e. The inclination angle α of the hydraulic fracturing borehole is determined by... Determine that R is the radius of the hydraulic fracturing fracture, and the calculation formula is:

[0017]

[0018] Where: q is the pumping rate; t is the pumping time; H is the suture height; v is Poisson's ratio; E is the elastic modulus; ρ is the average pumping pressure; p is the fracture closure pressure; C is the dynamic comprehensive filtration coefficient.

[0019] Considering that sufficient space should be left above the pre-splitting layer to place the sealing device, the drilling length is determined. m;

[0020] Angle between the hydraulic fracturing boreholes on both sides and the roadway cross section The calculation formula is:

[0021]

[0022] In the formula, Crack width D x When the radius is 0.01m, the fracture radius is determined by the relationship between the fracture width and the fracture root width: D x =0.01

[0023]

[0024] In the formula: The radius of the hydraulic fracturing crack; This represents the width at the root of the crack.

[0025] Preferably, in S3, the drilling rig is used to construct the hydraulic fracturing borehole in the middle according to the design parameters. When the ordinary drill bit is used to drill to the middle height of the confined water zone, the slotting drill bit is replaced to construct the slot. When the slotting drill bit reaches the bottom of the borehole, the slotting is made. During the slotting process, the progress of the slotting is judged by observing the water flowing out of the hydraulic fracturing borehole. After the slotting is completed, the slotting drill bit is withdrawn, and the ordinary drill bit is replaced to continue drilling until the hydraulic fracturing borehole is completed.

[0026] Preferably, in S5 and S7, the drainage system includes a water collector, a water guide pipe, a drainage system flow meter, a water storage tank, a water pump, a drain pipe, and a water tank. Water flows into the water collector through a borehole, and then is pumped out by the water pump through the water guide pipe and the water storage tank, and enters the water tank through the drain pipe.

[0027] Preferably, in S7, the parameters for the drainage borehole include determining the borehole location, diameter, inclination angle, length, and inter-bore angle; the starting point of the drainage borehole is set 5m from the face of the tunneling face, and construction is carried out towards the middle of the bottom boundary of the confined water zone, i.e. There are three drainage holes, each with a diameter of 65mm. These three drainage holes are arranged in a Y-direction, with a 1.5m distance between the starting points of adjacent holes. The inclination angle of the drainage holes is... Length of water-draining drill holes The angle between the two side drainage water drill holes and the middle drainage water drill hole is 30°.

[0028] Compared with the prior art, the advantages of the pre-fracturing and diversion method for confined aquifers overlying roadways disclosed in this invention are:

[0029] 1. This invention uses transient electromagnetic method to detect confined water areas in tunnel excavation sections, which can obtain water-rich areas of the overlying strata on the roof more directly and over a wider range. The obtained water-rich area range is more comprehensive and accurate, avoiding blind construction of water exploration holes, reducing construction time and workload, and reducing the occurrence of safety accidents.

[0030] 2. After determining the scope of the confined water zone, the present invention constructs hydraulic fracturing boreholes at the boundary of the water zone to perform hydraulic fracturing. The confined water zone is connected through the fracturing fractures. The confined water is depressurized by the fractures and then enters the borehole, avoiding direct drilling into the confined water zone and reducing the occurrence of water inrush accidents.

[0031] 3. To ensure the drainage effect, the present invention designs hydraulic fracturing borehole groups according to the radius and width of the fracturing cracks, so that a crack network can be formed between the boreholes, increasing the flow space; at the same time, after the water pressure of the pressurized water drops, the construction drainage boreholes are used to drain water into the pressurized water area simultaneously, improving drainage efficiency. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 Main view of the local water-rich area detected by transient electromagnetic method.

[0034] Figure 2 Top view of the local water-rich area detected by transient electromagnetic method.

[0035] Figure 3 Main view of the layout of hydraulic fracturing boreholes and drainage boreholes.

[0036] Figure 4 A top view showing the layout of hydraulic fracturing boreholes and drainage boreholes.

[0037] Figure 5 This is a front view schematic diagram of the drainage system.

[0038] Figure 6 This is a side view of the drainage system.

[0039] Figure 7 This is a schematic diagram of a hydraulic fracturing device.

[0040] In the diagram: 1-Confined water zone; 2-Transmitting coil; 3-Receiving coil; 4-Tunnel; 5-Drainage borehole; 6-Hydraulic fracturing borehole; 7-Sealing device; 8-Fracturing fracture; 9-Fracturing network; 10-High-pressure water pump; 11-High-pressure water pump pressure gauge; 12-Static water inlet pipeline; 13-Storage device; 14-Injection pipeline; 15-Water pump; 16-Storage device; 17-Collector; 18-Drainage pipe; 19-Water tank; 20-Water guide pipe; 21-Drainage system flow meter; 22-Injection steel pipe; 23-Groove opening; 24-Flow and water pressure monitoring instrument; 25-Manual pump; 26-Manual pump pressure gauge. Detailed Implementation

[0041] The specific embodiments of the present invention will be briefly described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0042] Figures 1-7 A preferred embodiment of the present invention is shown and analyzed in detail.

[0043] A pre-splitting diversion drainage method for the overlying confined water area of a roadway disclosed by the present invention includes the following steps:

[0044] S1. Use the transient electromagnetic method to detect the confined water area 1 at the ultra-front end of the roadway 4 heading face. If the measurement result shows no water-rich abnormal area, continue tunneling. If there is a water-rich abnormal area, determine the range of the confined water area 1 according to the measurement result; establish a spatial rectangular coordinate system with the tunneling heading face as point O, the forward direction along the tunneling direction as the X-axis, perpendicular to the tunneling direction as the Y-axis, and upward along the roof as the Z-axis. x1, x2, y1, y2, z1, z2 are the boundary coordinate values of the range of the confined water area 1 obtained by the transient electromagnetic method detection, x1 < x2, y1 < y2, z1 < z2, and the range of the confined water area 1 is (x1~x2, y1~y2, z1~z2). When x1 ≥ 30 m, continue tunneling the roadway 4. When x1 <> < 30 m, perform steps S2 - S8 for water drainage operation. As Figure 1 、 2 shown, when using the transient electromagnetic method to detect the confined water area 1 at the ultra-front end of the roadway 4 heading face, the transmitting coil 2 and the receiving coil 3 are arranged in parallel, and are arranged at multiple angles in a fan shape for the roof of the roadway 4. The angle between the coil directly in front and the floor of the roadway 4 is 30° and 60°. The transmitting coil 2 and the receiving coil 3 with an angle of 45° to the floor of the roadway 4 are arranged at both top positions, and the angle between different-direction coils is 60°.

[0045] S2. Design the parameters of six groups of hydraulic fracturing boreholes according to the range of the confined water area 1 and the specific geological conditions of the tunneling roadway 4. The parameters of the hydraulic fracturing boreholes 6 include the position, diameter, spacing, drilling inclination angle, borehole length of the hydraulic fracturing boreholes 6, and the angle between the two-side hydraulic fracturing boreholes 6 and the cross-section of the roadway 4.

[0046] As Figure 3 、 4 shown, the starting point of the hydraulic fracturing boreholes 6 is set at 15 m away from the tunneling working face heading face, and construction is carried out towards the boundary of the confined water area 1. There are three in total. The diameter of the hydraulic fracturing boreholes 6 is 65 mm; the three hydraulic fracturing boreholes 6 are arranged in the Y direction, and the spacing between the starting points of adjacent hydraulic fracturing boreholes 6 is 1.5 m. The pre-splitting horizon of the hydraulic fracturing is the middle part of the confined water area 1, that is , the inclination angle α of the hydraulic fracturing boreholes 6 is determined by , where R is the radius of the fracturing crack 8, and the calculation formula is:

[0047]

[0048] In the formula: q is the pumping rate; t is the pumping time; H is the fracture height; v is the Poisson's ratio; E is the elastic modulus; is the average pumping pressure; p is the fracture closure pressure; C is the dynamic comprehensive filtration loss coefficient;

[0049] Considering that a certain space should be left above the pre-splitting layer to place the sealing device 7, the drilling length is determined. m;

[0050] The angle between the hydraulic fracturing boreholes 6 on both sides and the cross section of roadway 4 The calculation formula is:

[0051]

[0052] In the formula, Crack width D x When the radius is 0.01m, the radius of the hydraulic fracturing fracture is determined by the relationship between the fracture width and the fracture root width: D x =0.01

[0053]

[0054] In the formula: The radius of the hydraulic fracturing fracture is 8. This represents the width at the root of the crack.

[0055] S3. Using the drilling rig according to the design parameters, construct the hydraulic fracturing borehole 6 in the middle. First, use a conventional drill bit to drill to the middle height of the pressurized water zone 1. Then, switch to a slotting drill bit to construct the slot opening 23. When the slotting drill bit is about to reach the end of the borehole, slow down the extension speed and reduce the drill rig's feed force to allow the slotting blades to open slowly, avoiding impact to the slotting drill bit. Slotting must be thorough; stop only after the slotting blades are fully open and have cut the borehole. During slotting, observe the water flowing out of the hydraulic fracturing borehole 6 to judge the progress. After completing the slotting, withdraw the slotting drill bit and replace it with a conventional drill bit to continue drilling until the hydraulic fracturing borehole 6 is completed. The slotting can be pre-created to determine the fracturing direction.

[0056] S4. After the hydraulic fracturing borehole 6 is drilled, it is flushed with static water and the sealing device 7 is installed and connected. After the sealing device 7 is installed, a pressure holding test is performed to verify its sealing effect. After confirming that the sealing device 7 can work normally, the hydraulic fracturing equipment is connected to carry out fracturing until the fracturing fracture 8 connects to the pressurized water zone 1, and water flows into the hydraulic fracturing borehole 6 through the fracture, at which point fracturing is stopped. Figure 7As shown, the equipment used includes a manual pump 25, a manual pump pressure gauge 26, a high-pressure water pump 10, a high-pressure water pump pressure gauge 11, a static pressure water inlet pipe 12, an energy storage device 13, a water injection pipe 14, a water injection steel pipe 22, and a flow and water pressure monitoring instrument 24. After the hydraulic fracturing borehole 6 is drilled, the sealing device 7 is installed and connected in the hydraulic fracturing borehole 6. After installation, static water is connected to test the sealing device 7 to check its tightness and the smoothness of the return water, ensuring normal operation. The manual pump 25 is connected to the accumulator 13 with a rubber hose, and then connected to the sealing device 7, using an "O" ring seal. Before starting to pressurize the manual pump 25, the shut-off valve is opened to allow static water to enter the accumulator 13. After the static water is full, the shut-off valve is closed. The manual pump 25 is pressurized to 10 MPa. The hydraulic fracturing borehole 6 is observed and the manual pump pressure gauge 26 is monitored to check whether the sealing device 7 can maintain pressure. If water flows out of the hydraulic fracturing borehole 6 or the pressure drops significantly, it indicates that the sealing has failed. All connections of the sealing device 7 and the sealing device 7 itself are checked to find and solve the problem, ensuring that the sealing device 7 works normally. During high-pressure water fracturing, use a type A crimp connection to connect the outlet of the high-pressure water pump 10 to the water injection pipeline 14, and then connect the water injection steel pipe 22, using an "O" ring for sealing; after checking that the connection is correct, turn on the water first and then the power to check whether the high-pressure water pump 10 is working properly. After the commissioning work is completed, the sealing device 7 is pushed to the set position by connecting the water injection steel pipe 22. After sealing and injecting water, fracturing is carried out from the slot of the hydraulic fracturing borehole 6. After fracturing begins, the pressure is slowly increased, and the data of the high-pressure water pump pressure gauge 11 and the manual pump pressure gauge 26 are recorded. The pressure is continuously increased until the pre-crack cracks open and the pressure suddenly drops. At this time, the pressure is maintained by water injection to allow the crack to continue to expand. The flow and pressure monitoring instrument 24 is observed to see if the water pressure rises and remains stable or if the fracturing time has reached 30 minutes. It is considered that the fracturing crack 8 has connected to the pressurized water zone 1 and the water flows into the hydraulic fracturing borehole 6 through the crack. Fracturing is then stopped. The fracturing equipment is removed, and the orifice pipe is installed to seal the hydraulic fracturing borehole 6. Then, the drainage system is installed to drain the water, and the data of the drainage system flow meter 21 is recorded.

[0057] S5. Remove the hydraulic fracturing equipment and install a borehole pipe to seal the hydraulic fracturing borehole 6. Install a drainage system to drain the water. (Example) Figure 5 , 6 As shown, the drainage system includes a water collector 17, a water guide pipe 20, a drainage system flow meter 21, a water storage tank 16, a water pump 15, a drain pipe 18, and a water tank 19. Water flows through the borehole into the water collector 17, then through the water guide pipe 20 and the water storage tank 16, where it is pumped by the water pump 15 and drained through the drain pipe 18 into the water tank 19. The water in the water tank 19 can provide a water source for subsequent hydraulic fracturing. The drainage system flow meter 21 is used to record drainage data.

[0058] S6. Repeat S3 to S5, construct hydraulic fracturing boreholes 6 on both sides of the central hydraulic fracturing borehole 6 according to the design parameters to form a flow-guiding fracture network 9.

[0059] S7. Based on the estimated water volume within the confined water zone 1, and recording the data from the drainage system flow meter 21, when the drainage volume reaches 1 / 5 of the estimated volume, design and construct 5 sets of drainage boreholes directly connected to the confined water zone 1. After construction, connect them to the drainage system for drainage. The parameters for the drainage boreholes 5 include determining the borehole location, diameter, inclination angle, length, and the angle between boreholes. The starting point of the drainage boreholes 5 is set 5m from the face of the tunneling face, facing the middle of the bottom boundary of the confined water zone 1. There are three drainage holes, each with a diameter of 65mm. These three drainage holes are arranged in a Y-direction, with a 1.5m distance between the starting points of adjacent holes. The inclination angle of the drainage holes is... Drainage hole length 5 The angle between the two side drainage holes 5 and the middle drainage hole 5 is 30°.

[0060] S8. Real-time monitoring of water pressure and flow rate is conducted using 5 pressure gauges at the drainage boreholes and 21 flow meters in the drainage system to evaluate the drainage effect. If any abnormal data is detected, the drainage operation is stopped immediately and the boreholes are sealed. After the drainage is completed, the drainage system is dismantled and the boreholes are sealed.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make and use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit and scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for pre-splitting and guiding and draining overburden water in a roadway, characterized in that, The method comprises the following steps: S1, using transient electromagnetic method to detect the pressure water area (1) of the heading advance end of the roadway (4), if the measurement result shows no water-rich abnormal area, continue to excavate, if there is a water-rich abnormal area, determine the range of the pressure water area (1) according to the measurement result; establish a space rectangular coordinate system with the heading advance point as O point, the front along the excavation direction as X axis, perpendicular to the excavation direction as Y axis, upward along the roof as Z axis, x1, x2, y1, y2, z1, z2 are the boundary coordinate values of the pressure water area (1) range obtained by transient electromagnetic method detection, x1 30 m, continue to excavate the roadway (4), x1 30 m, execute steps S2-S8 to perform water drainage operation; S2, designing the parameters of the hydraulic fracturing borehole (6) according to the range of the confined water area (1) and the specific geological conditions of the tunneling roadway (4); S3, constructing the middle hydraulic fracturing borehole (6) according to the design parameters, and slotting in the hydraulic fracturing borehole (6); S4, after the hydraulic fracturing borehole (6) is drilled, the hydraulic fracturing borehole (6) is flushed by using static pressure water, and a sealing device (7) is installed, after the sealing device (7) is installed, pressure maintaining test is performed to verify the sealing effect, after it is determined that the sealing device (7) can work normally, hydraulic fracturing equipment is connected to perform fracturing until the fracturing cracks (8) are connected to the confined water area (1), water flows into the hydraulic fracturing borehole (6) through the cracks, and the fracturing is stopped; S5, the hydraulic fracturing equipment is withdrawn, and a hole pipe is installed to seal the hydraulic fracturing borehole (6), a drainage system is installed to drain water, and the data of the flow meter (21) of the drainage system is recorded; S6, the hydraulic fracturing boreholes (6) on both sides of the middle hydraulic fracturing borehole (6) are constructed repeatedly to form a diversion crack network (9); S7, the water volume is estimated according to the range of the confined water area (1), and the data of the flow meter (21) of the drainage system is recorded, when the drainage volume reaches 1 / 5 of the estimated water volume, a drainage borehole (5) is designed and constructed to be directly connected to the confined water area (1), and after the construction is completed, the drainage system is connected to drain water; S8, the water gushing pressure and water gushing volume are monitored in real time through the pressure gauge at the drainage borehole (5) and the flow meter (21) of the drainage system, the drainage effect is evaluated, if the data is abnormal, the drainage operation is stopped in time, and the borehole is sealed, after the drainage is completed, the drainage system is removed, and the borehole is closed.

2. The method according to claim 1, wherein, In S1, when the transient electromagnetic method is used to detect the confined water area (1) at the front end of the tunnel (4), the transmitting coil (2) and the receiving coil (3) are arranged in parallel, and the tunnel (4) roof is arranged in a fan-shaped multi-angle manner, the angle between the front coil and the tunnel (4) floor is 30° and 60°, the angle between the side roof position and the tunnel (4) floor is 45°, and the angle between the different direction coils is 60°.

3. The method of claim 1, wherein the method is characterized by, In S2, the parameters of the hydraulic fracturing borehole (6) include the position, diameter and spacing of the hydraulic fracturing borehole (6); the starting point of the hydraulic fracturing borehole (6) is arranged at a position 15 m away from the tunneling face, and the hydraulic fracturing borehole (6) is constructed towards the boundary of the confined water area (1), there are three hydraulic fracturing boreholes (6), and the diameter of the hydraulic fracturing borehole (6) is 65 mm; the three hydraulic fracturing boreholes (6) are arranged in the Y direction, and the spacing between the starting points of the adjacent hydraulic fracturing boreholes (6) is 1.5 m.

4. The method according to claim 3, wherein, In S2, the parameters of the hydraulic fracturing borehole (6) further include a drilling inclination angle, a borehole length, and an angle between the two hydraulic fracturing boreholes (6) and the roadway (4) section; the pre-fracturing layer position of the hydraulic fracturing is the middle part of the confined water area (1), i.e. , the hydraulic fracturing borehole (6) inclination angle α is determined by , wherein R is the radius of the fracturing fracture (8), and the calculation formula is: where q is the pumping rate; t is the pumping time; H is the height of the fracture; v is the Poisson's ratio; E is the modulus of elasticity; is the average pumping pressure; p is the fracture closure pressure; C is the dynamic composite fluid loss coefficient; Considering that a certain space should be left above the pre-splitting horizon for placing the hole sealer (7), the length of the borehole is determined m; The included angle between the two hydraulic fracturing boreholes (6) and the roadway (4) cross section The calculation formula is: In the formula, Crack width D x When the radius is 0.01m, the radius of the hydraulic fracturing crack (8) is determined by the relationship between the crack width and the crack root width: D x =0.01 wherein: is the radius of the fracture (8); is the fracture tip width.

5. The method of claim 1, wherein the method is characterized by, In S3, the middle hydraulic fracturing borehole (6) is constructed according to the design parameters, a common drill bit is used to drill into the middle height of the confined water area (1), a slotting drill bit is replaced to construct a slotting opening (23), when the slotting drill bit reaches the bottom of the borehole, slotting is performed, the slotting process is judged by observing the water flowing out of the hydraulic fracturing borehole (6), after the slotting is completed, the slotting drill bit is withdrawn, a common drill bit is replaced to continue drilling, and the drilling of the hydraulic fracturing borehole (6) is completed.

6. The method of claim 1, wherein the method is characterized by, In S5 and S7, the drainage system comprises a water collector (17), a water guide pipe (20), a drainage system flow meter (21), a water reservoir (16), a water pump (15), a drain pipe (18), and a water sump (19). Water flows into the water collector (17) through the borehole, and then flows through the water guide pipe (20) and the water reservoir (16) and is pumped by the water pump (15) to the water sump (19) through the drain pipe (18).

7. The method of claim 1, wherein the method further comprises, In S7, the parameters of the water drainage borehole (5) include determining the borehole position, diameter, inclination, length and angle between boreholes; the starting point of the water drainage borehole (5) is set at 5 m away from the heading face, and is constructed towards the middle of the bottom boundary of the confined water area (1), that is , there are three water drainage boreholes, and the diameter of the borehole is 65 mm; the three water drainage boreholes (5) are arranged in the Y direction, and the distance between the starting points of adjacent water drainage boreholes (5) is 1.5 m; the inclination of the water drainage borehole (5) is , the length of the water drainage borehole (5) is , and the included angle between the two side water drainage boreholes (5) and the middle water drainage borehole (5) is 30°.

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