Water-rich tunnel water and mud bursting blocking and draining assembly type structure and safe construction method

Abstract

The present application relates to the technical field of tunnel, especially to a water-rich tunnel water and mud bursting blocking and draining assembly type structure and safe construction method. The water-rich tunnel water and mud bursting blocking and draining assembly type structure comprises a prefabricated concrete slab, a drainage pipe mounting hole, a pore water pressure gauge mounting hole, a drainage sleeve positioning hole and a grouting positioning hole are arranged in the prefabricated concrete slab, the drainage pipe mounting hole is located at the center position of the prefabricated concrete slab, the pore water pressure gauge mounting hole is located at the bottom of the drainage pipe mounting hole, and the grouting positioning hole is located at the outside of the drainage pipe mounting hole. The water-rich tunnel water and mud bursting blocking and draining assembly type structure and safe construction method provided by the present application utilizes the deep drainage sleeve to realize the discharge of high-pressure water in the deep surrounding rock, deep interception and blocking of water and mud bursting supply; the prefabricated concrete slab is used to quickly block the water and mud bursting position, the excess water is discharged through the reserved drainage hole, the shotcrete sealing of the working face is not needed, the exposure time of the surrounding rock is reduced, the personnel are avoided from facing the high-pressure water impact, and the on-site assembly and disassembly are convenient.

Description

Technical Field

[0001] This invention relates to the field of tunnel technology, and in particular to a prefabricated structure for plugging and draining water and mud in water-rich tunnels and a safe construction method therefor. Background Technology

[0002] The western region is characterized by numerous mountains and valleys, with well-developed karst formations and faults, posing a constant threat of water and mud inrushes during tunnel construction. These inrushes primarily occur because the insulating rock mass between the tunnel working face (face and excavation outline) and the hazardous structure is too thin. Under construction disturbance, this insulating rock mass suddenly ruptures, leading to a large-scale outburst of mud and water mixture. Prolonged mud and water outbursts can also trigger other disasters, such as softening and instability of the surrounding rock, the formation of underground cavities, surface subsidence, groundwater depletion, and destruction of surface vegetation.

[0003] Due to the complex causes and occurrence conditions of water and mud inrush disasters in tunnels, existing theoretical analyses and numerical simulations are insufficient to accurately simulate the real tunnel environment and the occurrence process of water and mud inrush. Furthermore, advanced geological prediction methods used in the field, such as seismic wave reflection, ground-penetrating radar, and advanced drilling, are significantly affected by environmental interference and personnel experience, making it difficult to accurately identify the water and mud inrush structures ahead of the tunnel face. Therefore, water and mud inrush problems are unavoidable during construction. Currently, the main treatment solutions for water and mud inrush are "grouting consolidation and lining reinforcement." However, for high-pressure, water-rich tunnels, the grout is dispersed by high-pressure water before solidification, resulting in poor grouting effects. Therefore, an improved solution that addresses the shortcomings of existing technologies is needed. Summary of the Invention

[0004] Therefore, it is necessary to provide a prefabricated structure and safe construction method for plugging and draining water and mud in water-rich tunnels, in order to solve the technical problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A prefabricated structure for plugging and draining water and mud in water-rich tunnels, including

[0007] A precast concrete slab has drainage pipe installation holes, pore water pressure gauge installation holes, drainage sleeve positioning holes, and grouting positioning holes inside. The drainage pipe installation holes are located at the center of the precast concrete slab, the pore water pressure gauge installation holes are located at the bottom of the drainage pipe installation holes, the grouting positioning holes are located outside the drainage pipe installation holes, and the drainage sleeve positioning holes are located inside the four corners of the precast concrete slab.

[0008] Drainage sleeve, located inside the positioning hole of the drainage sleeve;

[0009] Drain pipe, located inside the drain pipe mounting hole;

[0010] The rubber sealing ring is located inside the drain pipe mounting hole and the pore water pressure gauge mounting hole;

[0011] The pore water pressure gauge is located inside the mounting hole of the pore water pressure gauge.

[0012] The reading instrument is connected to the pore water pressure gauge via a data cable;

[0013] Grout stopper, used to be inserted into the inside of the grouting positioning hole;

[0014] Double-layer steel mesh is located inside the precast concrete slab.

[0015] As a preferred embodiment of the prefabricated structure for blocking and draining water and mud in a water-rich tunnel provided by the present invention, the precast concrete slab is a square structure or an irregular shape.

[0016] As a preferred embodiment of the prefabricated structure for blocking and draining water and mud in a water-rich tunnel provided by the present invention, the precast concrete slab is a square structure located in the middle of the tunnel face.

[0017] As a preferred embodiment of the prefabricated structure for plugging and draining water and mud in a water-rich tunnel provided by the present invention, the precast concrete slab is an irregularly shaped structure located at the edge of the tunnel face.

[0018] As a preferred embodiment of the prefabricated structure for blocking and draining water and mud in a water-rich tunnel provided by the present invention, the tail of the drainage sleeve extends out of the drainage sleeve positioning hole, and a pad, a washer and a nut are installed in sequence at one end of the drainage sleeve.

[0019] A safe construction method for a prefabricated structure for plugging and draining water and mud in water-rich tunnels, applicable to any of the above, comprises the following steps:

[0020] S1: After a sudden water or mud inrush occurs in the tunnel, initial shotcrete leveling is carried out around the location of the sudden water or mud inrush to form a shotcrete leveling layer, so that the precast concrete slabs can be tightly bonded to the surrounding rock.

[0021] S2: After the shotcrete leveling, advanced horizontal geological drilling rigs are used to drill holes around the locations of water and mud inrush. Drainage sleeves are used to follow the drilling in a synchronous manner. The drilling direction is parallel to the outer normal direction of the face, and the drilling spacing is consistent with the spacing of the drainage sleeve positioning holes in the precast concrete slab.

[0022] S3: Extend the end of the last section of the drain sleeve in step S2 out of the drain sleeve positioning hole;

[0023] S4: After the drainage sleeve is installed in step S3, drain the water after setting it aside;

[0024] S5: When the water pressure and volume of the water and mud sprayed in step S4 decrease, the precast concrete slab is lifted by a robotic arm and positioned outside the drainage sleeve through the positioning hole of the drainage sleeve. Then the precast concrete slab is pressed tightly and attached to the sprayed concrete leveling layer.

[0025] Place the pad on the outside of the drainage sleeve and fit it tightly against the precast concrete slab. Then place the washer and nut, and tighten the nut with a pneumatic wrench to complete the installation of the precast concrete slab.

[0026] S6: Insert the rubber sealing ring into the drainage pipe installation hole of the precast concrete slab, screw the drainage pipe into the corresponding rubber sealing ring, and discharge the water from the water and mud protrusion points.

[0027] S7: Place the rubber sealing ring into the pore water pressure gauge installation hole of the precast concrete slab, and screw the pore water pressure gauge into the corresponding rubber sealing ring. If there is no water seepage around the rubber sealing ring corresponding to the pore water pressure gauge, it indicates that the seal is good and proceed to the next step. Otherwise, remove the pore water pressure gauge and rubber sealing ring and reinstall them.

[0028] S8: Lead out the data cable of the pore water pressure gauge, connect the data cable interface to the reading instrument, and determine the water pressure generated by the sudden water and mud on the precast concrete slab by the value of the reading.

[0029] S9: Use an advanced horizontal geological drilling rig to drill holes in the reserved grouting positioning holes;

[0030] S10: After drilling is completed in step S9, install a grout stop plug on the reserved grouting positioning hole, insert the grouting pipe to perform advanced grouting at the working face, and stop grouting after the grouting pressure reaches the design pressure and remains stable for a period of time, and seal the grouting positioning hole; repeat the operation until all grouting is completed.

[0031] S11: After the pore water pressure gauge is installed, the water pressure behind the precast concrete slab is continuously monitored. If the water pressure decreases and reaches a safe value after the pre-grouting at the working face is completed, the treatment of water and mud inrush is completed.

[0032] S12: After the water and mud inrush is treated, the precast concrete slab is removed, and the drainage sleeve is pulled out mechanically to proceed to the next step of construction.

[0033] In a preferred embodiment of the safe construction method of the prefabricated structure for blocking and draining water and mud in a water-rich tunnel provided by the present invention, in step S5, a double-layer steel mesh is provided inside the precast concrete slab.

[0034] As a preferred embodiment of the safe construction method of the prefabricated structure for blocking and draining water and mud in a water-rich tunnel provided by the present invention, in step S12, if multiple precast concrete slabs are used for assembly, they are disassembled according to the principle of "top to bottom, periphery to center".

[0035] It is clear without a doubt that the technical solution described above in this application can solve the technical problem that this application aims to address.

[0036] Meanwhile, through the above technical solutions, the present invention has at least the following beneficial effects:

[0037] This invention provides a prefabricated structure and safe construction method for blocking and draining water and mud inrushes in water-rich tunnels. It utilizes a deep drainage sleeve to discharge high-pressure water deep within the surrounding rock, achieving deep interception and blocking the replenishment of water and mud inrushes. Precast concrete slabs are used to quickly seal the locations of water and mud inrushes, with excess water draining through pre-reserved drainage holes, eliminating the need for shotcrete sealing of the tunnel face, reducing the exposure time of the surrounding rock, and preventing personnel from facing the impact of high-pressure water. Grouting positioning holes are used to pre-grout and seal the locations of water and mud inrushes at the tunnel face, reinforcing the surrounding rock. Pore water is also utilized... The pressure gauge monitors the water pressure behind the precast concrete slab to assess the treatment of water and mud inrushes, providing guidance for subsequent research and construction. It also integrates rapid sealing, grouting reinforcement, and monitoring measurement. The prefabricated structure for plugging and draining water and mud inrushes is reusable, with reasonable component dimensions, eliminating the need for large assembly equipment. On-site assembly and disassembly are convenient, significantly reducing the cost and treatment time for water and mud inrushes. After the water and mud inrushes are plugged and drained, the precast concrete slab can be partially or completely disassembled for normal construction, greatly ensuring construction safety. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a partial assembly cross-sectional view of the prefabricated structure for blocking and draining water and mud at the working face of the present invention.

[0040] Figure 2 This is a schematic diagram of the prefabricated structure for blocking and draining water and mud at the working face according to the present invention.

[0041] Figure 3 This is a partial assembly diagram of the prefabricated structure for blocking and draining water and mud at the working face of the present invention;

[0042] Figure 4This is an overall assembly diagram of the upper step of the prefabricated structure for blocking and draining water and mud at the working face of the present invention.

[0043] Figure 5 This is a graph showing the pore water pressure monitoring results of the present invention;

[0044] Figure 6 This is a schematic diagram of the precast concrete slab structure of the present invention;

[0045] Figure 7 This is a schematic diagram of the arrangement of the reinforcing mesh in the precast concrete slab of the present invention.

[0046] In the diagram: 1. Precast concrete slab; 2. Drainage sleeve; 3. Gasket; 4. Washer; 5. Nut; 6. Drainage pipe; 7. Rubber sealing ring; 8. Pore water pressure gauge; 9. Reading instrument; 10. Grout stop plug; 11. Drainage pipe installation hole; 12. Pore water pressure gauge installation hole; 13. Drainage sleeve positioning hole; 14. Grouting positioning hole; 15. Double-layer steel mesh; 16. Shotcrete leveling layer; 17. Grouting fluid. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0048] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0049] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0050] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] Example 1

[0052] Reference Figures 1-7 A prefabricated structure for plugging and draining water and mud in water-rich tunnels, including

[0053] The precast concrete slab 1 has a pre-drainage pipe installation hole 11 located at the center of its surface. A pore water pressure gauge installation hole 12 is also pre-drained inside the slab, located at the bottom of the drainage pipe installation hole 11. Four grouting positioning holes 14 are pre-drained around the drainage pipe installation hole 11. Four drainage sleeve positioning holes 13 are pre-drained at the four corners of the slab. A double-layer steel mesh 15 is installed inside the slab to improve its tensile strength. The slab is fitted tightly against the location of water and mud inrush at the working face, and through partial or overall assembly, it allows for rapid sealing, drainage, and reinforcement of the surrounding rock inrush at the working face.

[0054] Preferably, the precast concrete slab 1 is a square or irregular shape. The square shape is used in the middle part of the tunnel face, and the irregular shape is used in the edge part of the tunnel face. The curvature of the irregular shape is consistent with the tunnel excavation outline.

[0055] The rubber sealing ring 7 is placed inside the drain pipe mounting hole 11 and the pore water pressure gauge mounting hole 12 to prevent leakage around the drain pipe mounting hole 11 and the pore water pressure gauge mounting hole 12.

[0056] Drainage casing 2 is a wall-protecting casing used in drilling with an advanced horizontal geological drilling rig. Drainage casing 2 is inserted into the drainage casing positioning hole 13 along with the drill bit of the advanced horizontal geological drilling rig. The tail of the last section of drainage casing 2 is milled with threads, and the tail of the last section of drainage casing 2 extends 15-20cm to install the pad 3, washer 4, and nut 5. It is mainly used to drain high-pressure water from deep within the working face and to install precast concrete slabs 1.

[0057] The drainage sleeve positioning hole 13 is connected to the drainage sleeve 2 and is used to install the precast concrete slab 1.

[0058] Grouting positioning hole 14 is used to determine the grouting and sealing position. Drilling and grouting are performed in the grouting positioning hole 14.

[0059] The grout stopper 10 is used to insert into the grouting positioning hole 14 to prevent grout from returning.

[0060] Washer 4 and nut 5 are tightened to the end of the last drainage sleeve 2 to fix the precast concrete slab 1 to the excavated face.

[0061] A pore water pressure gauge 8, along with a rubber sealing ring 7, is installed in the reserved pore water pressure gauge mounting hole 12 and connected to a reading instrument 9 via a data cable. It is used to measure the water pressure behind the precast concrete slab 1.

[0062] The reading instrument 9 is connected to the pore water pressure gauge 8 and is used to display the pore water pressure value.

[0063] Drain pipe 6, along with rubber sealing ring 7, is installed in the reserved drain pipe installation hole 11 to drain the mud and water mixture behind the precast concrete slab 1.

[0064] In this embodiment, Figure 2 In this context, P0 represents the pore water pressure, and F... S This refers to the axial force of the anchor bolt.

[0065] Example 2

[0066] Based on the above-described embodiment one, a safe construction method is disclosed, the steps of which are as follows:

[0067] Step 1: After a water or mud inrush occurs in the tunnel, initial shotcrete leveling is performed around the location of the water or mud inrush, forming a shotcrete leveling layer 16. This ensures that the precast concrete slab 1 can adhere tightly to the surrounding rock, preventing mud and water from seeping out from behind the precast concrete slab 1. In this embodiment, C25 shotcrete is used for the initial shotcrete, with a shotcrete thickness of 8cm. In other embodiments, the thickness of the initial shotcrete is adjusted according to the roughness of the surrounding rock after excavation.

[0068] Step 2: After leveling with shotcrete, use an advanced horizontal geological drilling rig to drill holes around the location of water and mud inrush. When drilling, use drainage sleeve 2 to follow the drilling in a synchronous manner. A total of four holes are set up. The drilling direction is parallel to the outer normal direction of the working face. The spacing between the holes is consistent with the spacing of the drainage sleeve positioning holes 13 in the precast concrete slab 1. The rectangular frame formed by the four holes should cover the area of ​​water and mud inrush as much as possible.

[0069] In this embodiment, the borehole spacing is 1.8m*1.8m, the borehole frame completely covers the area of ​​water and mud inrush, the borehole depth is 10-20m, and the borehole diameter is 70-80mm.

[0070] Step 3: Drainage casing 2 is inserted into the hole along with the drill bit. Drainage casing 2 is a wall-protecting casing used in advanced horizontal geological drilling. The last section of drainage casing 2 has threads milled at its tail, which extends 15-20cm to accommodate the pad 3, washer 4, and nut 5. The drill bit is then removed from drainage casing 2, leaving it inside the hole to discharge high-pressure water. This is primarily used to drain high-pressure water from deep within the working face, reducing water pressure at locations of water and mud inrushes.

[0071] Step 4: After the drainage sleeve 2 is installed, leave it for a period of time and then drain the water. The drainage sleeve 2 will intercept and release the high-pressure water deep in the surrounding rock, block the supply of water and mud inrush, and reduce the water pressure and volume ejected from the water and mud inrush location at the working face.

[0072] Step 5: After the water pressure and volume from the sudden water and mud spray have significantly decreased, lift the precast concrete slab 1 with a robotic arm, aligning the drainage sleeve positioning hole 13 of the precast concrete slab 1 with the reserved drainage sleeve 2. After the drainage sleeve 2 is inserted into the drainage sleeve positioning hole 13, press the precast concrete slab 1 tightly against the shotcrete leveling layer 16 to prevent mud and water from seeping out from the edges. Place the pad 3 on the drainage sleeve 2, ensuring it fits tightly against the precast concrete slab 1. Then place the washer 4 and nut 5, and tighten the nut 5 using a pneumatic wrench. Secure the precast concrete slab 1 with the nut 5, completing the installation of the precast concrete slab 1.

[0073] Furthermore, the precast concrete slab 1 in step five is made of C30 concrete. The dimensions of the precast concrete slab 1 are: length 200cm, width 200cm, and thickness 10cm. A double-layer steel mesh 15 with φ6@100 gauge is installed inside the precast concrete slab 1, with a spacing of 60mm between the two layers. The precast concrete slab 1 has a 60mm diameter drainage pipe installation hole 11, a 40mm diameter pore water pressure gauge installation hole 12, and a 45mm diameter grouting positioning hole 14.

[0074] Step Six: Insert the rubber sealing ring 7 into the drainage pipe mounting hole 11 of the precast concrete slab 1, then screw the drainage pipe 6 into the corresponding rubber sealing ring 7 to begin draining water from the water and mud leakage points. The rubber sealing ring 7 is made of soft rubber, and there is only one ring. The outer diameter of the rubber sealing ring 7 is 60mm, and the inner diameter is 50mm. The drainage pipe 6 is made of steel, with an outer diameter of 50mm and a wall thickness of 2mm.

[0075] Step 7: Insert the rubber sealing ring 7 into the pore water pressure gauge mounting hole 12 of the precast concrete slab 1. Then screw the pore water pressure gauge 8 into the corresponding rubber sealing ring 7 and observe the sealing condition. After the rubber sealing ring 7 is supported, it should completely fill the gap between the pore water pressure gauge mounting hole 12 and the pore water pressure gauge 8. Observe for several minutes. If there is no water seepage around the rubber sealing ring 7, the seal is good and the next step can be carried out. Otherwise, remove the pore water pressure gauge 8 and the rubber sealing ring 7 and reinstall them. The rubber sealing ring 7 is made of soft rubber, and there is only one. The outer diameter of the rubber sealing ring 7 is 40mm and the inner diameter is 30mm. The pore water pressure gauge 8 is a vibrating wire pore water pressure gauge with a water pressure measurement range of 1MPa. Before using the pore water pressure gauge 8, remove the permeable stone at the front end and soak the permeable stone in water to remove the internal air. The permeable stone should not be in contact with air before the pore water pressure gauge 8 is installed.

[0076] Step 8: Lead out the data cable of the pore water pressure gauge 8, keeping the data cable interface away from areas prone to sudden water or mud inrush and construction disturbances, in a safe area to prevent the data cable interface from being submerged or broken. Connect the data cable interface to the reading instrument 9. The water pressure generated by the sudden water or mud inrush on the precast concrete slab 1 can be determined by the reading value. A handheld data acquisition device is used for the reading instrument 9. Connect the external connection port of the pore water pressure gauge 8 to the reading instrument 9 and record the initial water pressure on the reading instrument 9.

[0077] Step 9: Drill holes in the reserved grouting positioning holes 14 using an advanced horizontal geological drilling rig. The drilling depth is determined according to the actual situation, and can be 3 to 20m. The drilling depth is 8m. After drilling is completed, use high-pressure water to clean the hole. If the water flow in the hole is large, the hole may not need to be cleaned.

[0078] Step 10: After drilling, clean the hole and grout. Install the grout stop plug 10 on the reserved grouting positioning hole 14, insert the grouting pipe, and perform pre-grouting at the working face. Stop grouting after the grouting pressure reaches the design pressure and remains stable for a period of time, and seal the grouting positioning hole 14. Proceed to the next hole for grouting until all grouting is completed. The grouting fluid 17 uses a cement-water glass dual-liquid grout, with the addition of an early-strength agent and an expansion agent. The grouting design pressure is 1.5 MPa. After reaching the design pressure, maintain the pressure for 20 minutes. The grout injection rate should not exceed 1 L / min. Stop grouting, pull out the grouting pipe, and seal the grouting positioning hole 14.

[0079] Step 11: After the pore water pressure gauge 8 is installed, the water pressure behind the precast concrete slab 1 is continuously monitored and the monitoring curve is plotted. If the water pressure begins to decrease and reaches the design safety value after the pre-grouting at the working face is completed, the treatment of water and mud inrush is completed.

[0080] Step Twelve: After treating the sudden water and mud inrush, remove the precast concrete slab 1 and mechanically pull out the drainage sleeve 2 to proceed to the next stage of construction. If multiple precast concrete slabs 1 are used for assembly, dismantle them according to the principle of "top to bottom, perimeter to center," based on... Figure 4 The items are removed and stacked neatly in ascending order of size, according to the markings, for continuous use.

[0081] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A safe construction method for a prefabricated structure for plugging and draining water and mud in water-rich tunnels, characterized in that, The safe construction method adopts a prefabricated structure for plugging and draining water and mud in water-rich tunnels. This prefabricated structure includes: A precast concrete slab (1) is provided with a drainage pipe installation hole (11), a pore water pressure gauge installation hole (12), a drainage sleeve positioning hole (13), and a grouting positioning hole (14); a grout stop plug (10) for inserting into the grouting positioning hole (14); and a double-layer steel mesh (15) located inside the precast concrete slab (1). The steps of the safe construction method are as follows: S1: After a sudden water or mud inrush occurs in the tunnel, initial shotcrete leveling is carried out around the location of the sudden water or mud inrush to form a shotcrete leveling layer (16), so that the precast concrete slab (1) is tightly bonded to the surrounding rock. S2: After the shotcrete leveling, advanced horizontal geological drilling rigs are used to drill holes around the locations of sudden water and mud inrush. When drilling, drainage sleeves (2) are used to follow up synchronously. The drilling direction is parallel to the direction of the outer normal of the face, and the drilling spacing is consistent with the spacing of the drainage sleeve positioning holes (13) in the precast concrete slab (1). S3: Extend the end of the last section of the drain sleeve (2) in step S2 out of the drain sleeve positioning hole (13). S4: After the drainage sleeve (2) is installed in step S3, drain the water after setting it aside; S5: When the water pressure and volume of the water and mud sprayed in step S4 decrease, the precast concrete slab (1) is lifted by a mechanical arm and positioned on the outside of the drainage sleeve (2) through the positioning hole (13) of the drainage sleeve. Then the precast concrete slab (1) is pressed tightly and attached to the sprayed concrete leveling layer (16). Place the pad (3) on the outside of the drainage sleeve (2) and fit it tightly against the precast concrete slab (1). Then place the washer (4) and nut (5), and tighten the nut (5) with a pneumatic wrench to complete the installation of the precast concrete slab (1). S6: Place the rubber sealing ring (7) into the drain pipe installation hole (11) of the precast concrete slab (1) and screw the drain pipe (6) into the corresponding rubber sealing ring (7); S7: Place the rubber sealing ring (7) into the pore water pressure gauge installation hole (12) of the precast concrete slab (1), and screw the pore water pressure gauge (8) into the corresponding rubber sealing ring (7). If there is no water seepage around the rubber sealing ring (7) corresponding to the pore water pressure gauge (8), it indicates that the seal is good and the next step is carried out. Otherwise, remove the pore water pressure gauge (8) and the rubber sealing ring (7) and reinstall them. S8: Lead out the data line of the pore water pressure gauge (8), connect the data line interface to the reading instrument (9), and judge the water pressure generated by the water and mud inrush on the precast concrete slab (1) by the value of the reading; S9: Drill holes using an advanced horizontal geological drilling rig in the reserved grouting positioning holes (14); S10: After drilling is completed in step S9, install a grout stop plug (10) on the reserved grouting positioning hole (14), insert the grouting pipe to perform advanced grouting at the working face, and stop grouting after the grouting pressure reaches the design pressure and remains stable for a period of time, and seal the grouting positioning hole (14); repeat the operation until all grouting is completed. S11: After the pore water pressure gauge (8) is installed, the water pressure behind the precast concrete slab (1) is continuously monitored. If the water pressure decreases and reaches a safe value after the grouting is completed at the working face, the treatment of water and mud inrush is completed. S12: After the water and mud inrush is treated, the precast concrete slab (1) is removed, and the drainage sleeve (2) is pulled out by mechanical means to carry out the next construction step.

2. The safe construction method of the prefabricated structure for plugging and draining water and mud in water-rich tunnels according to claim 1, characterized in that: The drainage pipe installation hole (11) is located at the center of the precast concrete slab (1), the pore water pressure gauge installation hole (12) is located at the bottom of the drainage pipe installation hole (11), the grouting positioning hole (14) is located outside the drainage pipe installation hole (11), and the drainage sleeve positioning hole (13) is located inside the four corners of the precast concrete slab (1). The drain sleeve (2) is located inside the drain sleeve positioning hole (13); The drain pipe (6) is located inside the drain pipe mounting hole (11); The rubber sealing ring (7) is located inside the drain pipe mounting hole (11) and the pore water pressure gauge mounting hole (12); The pore water pressure gauge (8) is located inside the pore water pressure gauge mounting hole (12); The reading instrument (9) is connected to the pore water pressure gauge (8) via a data cable.

3. The safe construction method of the prefabricated structure for plugging and draining water and mud in a water-rich tunnel according to claim 1, characterized in that, The precast concrete slab (1) is a square structure or an irregular structure.

4. The safe construction method of the prefabricated structure for plugging and draining water and mud in water-rich tunnels according to claim 1, characterized in that, The precast concrete slab (1) is a square structure and is located in the middle of the working face.

5. A safe construction method for a prefabricated structure for plugging and draining water and mud in a water-rich tunnel according to claim 1, characterized in that, The precast concrete slab (1) is an irregularly shaped structure located at the edge of the working face.

6. The safe construction method of the prefabricated structure for plugging and draining water and mud in a water-rich tunnel according to claim 1, characterized in that, The end of the drain sleeve (2) extends out of the drain sleeve positioning hole (13), and a pad (3), a washer (4) and a nut (5) are installed in sequence at one end of the drain sleeve (2).

7. A safe construction method for a prefabricated structure for plugging and draining water and mud in a water-rich tunnel according to claim 1, characterized in that, In step S5, a double-layer steel mesh (15) is provided inside the precast concrete slab (1).

8. A safe construction method for a prefabricated structure for plugging and draining water and mud in a water-rich tunnel according to claim 1, characterized in that, In step S12, if multiple precast concrete slabs (1) are used for assembly, they are disassembled according to the principle of "top to bottom, periphery to center".

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