A deep-buried tunnel groundwater seepage safety control system and method integrating discharge and injection

Abstract

The application discloses a deep-buried tunnel underground water seepage safety control system and method, and relates to the technical field of tunnel construction safety control. The system comprises a drainage and injection integrated pipe, a water collecting and purifying system and a water injection and pressurizing system. The drainage and injection integrated pipe comprises a water injection pipe and multiple main body pipes. A first main body pipe penetrates a reinforced ring layer of a tunnel and communicates with surrounding rock outside the reinforced ring layer. One end of the first main body pipe close to the surrounding rock is a first section concentric flower pipe. One end of the first main body pipe close to the tunnel center is a solid pipe. The first main body pipe and a second main body pipe are water-stopping sealed through a first flange and a water-stopping structure. The water injection pipe at least penetrates the first main body pipe and the first flange. A last main body pipe with a top end away from the reinforced ring layer is a second section concentric flower pipe. The end of the first main body pipe communicates with the water collecting and purifying system. The end of the water injection pipe communicates with the water injection and pressurizing system. The water collecting and purifying system communicates with the water injection and pressurizing system.

Description

A groundwater seepage safety control system and method integrating drainage and injection in deep buried tunnels Technical Field

[0001] This invention relates to the field of tunnel construction safety control technology, specifically to a groundwater seepage safety control system and method for deep buried tunnels that integrates drainage and injection. Background Technology

[0002] In the construction of highways, railways, and long-distance water conveyance projects in my country, tunnels account for a high proportion. These tunnels traverse complex geological structures and groundwater conditions, leading to frequent water inrush incidents during construction and causing significant loss of life and property. To ensure tunnel construction safety, it is necessary to reduce the groundwater head near the tunnel perimeter to a sufficiently low level or reinforce the loose layers of the tunnel to improve its resistance to groundwater pressure. Currently, the main method for addressing groundwater seepage safety in tunnels is drainage-grouting sealing. However, when the tunnel is deep, the groundwater pressure outside the tunnel perimeter is high, and the strata are highly water-rich, conventional grouting sealing techniques are insufficient to provide sufficiently safe construction conditions. In such cases, continuous drainage is the primary method to achieve safe construction conditions. Although drainage measures can reduce the groundwater pressure outside the reinforced tunnel perimeter to a safe level, providing conditions for tunnel construction, continuous groundwater discharge will cause serious damage to the regional groundwater environment and surface water and ecosystems. This impact can be catastrophic and irreversible, especially when the tunnel passes through ecologically sensitive areas. Balancing tunnel construction safety with regional water ecological environment protection is a major technical challenge currently facing deep-buried tunnel construction, and remains a blank area. Summary of the Invention

[0003] The present invention provides a groundwater seepage safety control system and method for deep buried tunnels that integrates drainage and injection, which solves the above-mentioned problems.

[0004] This invention provides an integrated drainage and injection system for groundwater seepage safety control in deep buried tunnels, comprising: an integrated drainage and injection pipe, a water collection and purification system, and a water injection and pressurization system;

[0005] The integrated injection and drainage pipe includes an injection pipe and multiple main pipe sections;

[0006] The first section of the main pipe passes through the reinforced layer of the tunnel and is connected to the surrounding rock outside the reinforced layer; the end of the first section of the main pipe closest to the surrounding rock is the first section of the concentric pipe; the end of the first section of the main pipe closest to the center of the tunnel is the solid pipe.

[0007] The first main pipe section and the second main pipe section are sealed with water by the first flange and the water-stopping structure;

[0008] The water injection pipe must pass through at least the first main pipe section and the first flange;

[0009] The last section of the main tube, furthest from the reinforcing ring at the top, is the second concentric tube.

[0010] The end of the main pipe in the first section is connected to the water collection and purification system; the end of the water injection pipe is connected to the water injection and pressurization system; the water collection and purification system is connected to the water injection and pressurization system.

[0011] Optionally, the injection and drainage pipe also includes an exhaust pipe and a groundwater pressure sensor;

[0012] The exhaust pipe passes through at least the first main pipe section and the first flange;

[0013] A groundwater pressure sensor is installed at the top of the exhaust pipe; an exhaust pipe valve is installed at the bottom of the exhaust pipe.

[0014] The groundwater pressure sensor is connected to the pressure control system of the water injection pressurization system;

[0015] A digital display valve is also installed at the end of the water injection pipe.

[0016] Optionally, the length of the vent pipe is set according to the inclination of the integrated vent pipe; when the integrated vent pipe is inclined upward, the vent pipe extends to the top of the main pipe; when the integrated vent pipe is horizontal or inclined downward, the vent pipe passes through the first section of the main pipe and the first flange.

[0017] Optionally, a first filter body is filled between the two concentric tubes of the first section;

[0018] The second section of the concentric flower tubes is filled with a second filter body between the two flower tubes.

[0019] Optionally, a joint sealant is provided between the outer surface of the main body of the first and second concentric tube sections and the gaps in the surrounding rock.

[0020] Optionally, a fixing ring is provided at the end of the water injection pipe, and the fixing ring and the inner wall of the main pipe are fixedly connected by connecting fasteners.

[0021] Optionally, it also includes a ring-shaped drain pipe and a ring-shaped water injection pipe;

[0022] The integrated injection and drainage pipes are arranged at 30° intervals along the radial direction of the tunnel, with the center of the tunnel as the origin. A total of 12 integrated injection and drainage pipes are arranged in each tunnel section.

[0023] The end of the first section of the main pipe of each integrated drainage and injection pipe is connected to the ring-shaped drainage pipe; and is connected to the water collection and purification system through the ring-shaped drainage pipe;

[0024] The end of the water injection pipe of each integrated injection and drainage pipe is connected to the ring-shaped water injection pipe; the water injection pressurization system is connected to the water injection pipe through the ring-shaped water injection pipe.

[0025] Optionally, the water collection and purification system includes: a drainage pressure device, a drainage connection pipe, a water collection tank, a third filter, and a sediment treatment device;

[0026] The drainage connection pipe is connected to the ring drainage pipe and the water collection tank respectively; the water collection tank is also connected to the water injection and pressurization system through the third filter body;

[0027] The sediment treatment device is located at the bottom of the collection tank.

[0028] Optionally, the water injection pressurization system includes: a water injection tank, a water injection connection pipe, a water injection pressure device, and a pressure control system;

[0029] The water injection connection pipe is connected to both the ring-shaped water injection pipe and the water injection pool; the water injection pressure device is located at the water injection connection pipe inlet and is connected to the pressure control system.

[0030] This invention also provides a method for integrated drainage and injection safety control of groundwater seepage in deep-buried tunnels, applicable to integrated drainage and injection safety control systems for groundwater seepage in deep-buried tunnels; the method includes:

[0031] Groundwater outside the reinforced concentric ring enters the first main pipe section through the first concentric flower pipe section;

[0032] Under the action of the drainage pressure device, the water enters the water collection and purification system's collection tank through the annular drainage pipe and drainage connection pipe connected to the end of the first main pipe section, and then the water enters the water injection tank of the water injection and pressurization system through the third filter body.

[0033] After the water enters the water injection pool of the water injection and pressurization system, the water is pressed into the annular water injection pipe and each water injection pipe connected to the annular water injection pipe through the water injection pressure device.

[0034] After the water enters the main pipe above the first concentric pipe through the water injection pipe, it enters the formation through the second concentric pipe under pressure.

[0035] The beneficial effects of this invention are as follows: Addressing the technical shortcomings in current research, this invention provides a groundwater seepage safety control system and method for deep-buried tunnels that integrates drainage and injection. It utilizes a concentric pipe section near the surrounding rock to drain groundwater from the vicinity of the tunnel's outer layer, reducing the pressure head in that area and preventing collapses or sudden water inrushes during tunnel construction, thus ensuring tunnel construction safety. Simultaneously, the drained groundwater is purified by a water collection and purification system, then injected into an injection pipe via a pressurization system. This water is then injected into the strata at a certain depth through a second concentric pipe section away from the reinforced layer, forming a stable groundwater seepage field with the first concentric pipe section used for drainage. This reduces the impact of tunnel drainage on the regional groundwater environment and surface water ecosystem, achieving a synergy between tunnel construction safety and ecological environmental protection. Furthermore, to address the limited space within tunnels, this invention proposes a structure with both drainage and injection functions—an integrated drainage and injection pipe. This significantly improves tunnel space utilization efficiency and, compared to separate drainage and injection methods, offers advantages such as smaller footprint, higher construction efficiency, and lower economic costs. Attached Figure Description

[0036] Figure 1 is a schematic diagram of a groundwater seepage safety control system for a deep-buried tunnel with integrated drainage and injection provided in Embodiment 2 of the present invention;

[0037] Figure 2 is a schematic diagram of the upward tilting structure of the integrated injection and discharge pipe provided in Embodiment 2 of the present invention;

[0038] Figure 3 is a schematic diagram of the downward tilting structure of the integrated injection and discharge pipe provided in Embodiment 2 of the present invention;

[0039] Figure 4 is a schematic diagram of the splicing structure of the first main pipe and the water injection pipe provided in Embodiment 2 of the present invention;

[0040] Figure 5 is a schematic diagram of the cross-sectional structure of the second concentric flower tube provided in Embodiment 2 of the present invention;

[0041] Figure 6 is a schematic diagram of the cross-sectional structure of the end of the main tube provided in Embodiment 2 of the present invention;

[0042] Figure 7 is a schematic diagram of the water collection and purification system and the water injection and pressurization system provided in Embodiment 2 of the present invention;

[0043] Figure 8 is a partial enlarged view of point A in Figure 1.

[0044] Attached reference numerals: 1-Integrated drainage and injection pipe; 2-Reinforcement ring; 3-Water flow direction; 4-1-Water collection and purification system; 4-2-Water injection and pressurization system; 5-Annular drainage pipe; 6-Annular water injection pipe; 7-Drainage connection pipe; 8-Second filter body; 9-Concentric flower pipe; 10-Main pipe; 11-Groundwater pressure sensor; 12-Exhaust pipe; 13-Sealing tape; 14-Water injection pipe; 15-Exhaust pipe valve; 16-Flange; 17-First filter body; 18-Digital display valve; 1 9-Silicone sealing ring; 20-Stainless steel connecting fastener; 21-Fixing ring; 22-Rubber ring; 23-Overflow pipe; 24-Overflow valve; 25-Collection tank; 26-Perforated plate; 27-Injection tank; 28-Pressure control system; 29-Injection connection pipe; 30-Third filter body; 31-Drain valve; 32-Drain pump; 33-Sand discharge valve; 34-Sludge pump; 35-Sand discharge pipe; 36-Cement base; 37-High-lift pressure pump; 38-Injection valve. Detailed Implementation

[0045] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0046] Example 1

[0047] This embodiment provides a groundwater seepage safety control system for deep buried tunnels that integrates drainage and injection, including: an integrated drainage and injection pipe, a water collection and purification system, and a water injection and pressurization system;

[0048] The integrated injection and drainage pipe includes a main pipe and an injection pipe; the main pipe consists of multiple sections.

[0049] The first section of the main pipe passes through the reinforced layer of the tunnel and is connected to the surrounding rock outside the reinforced layer; the end of the first section of the main pipe near the surrounding rock is the first concentric pipe; the end of the first section of the main pipe near the center of the tunnel is the solid pipe.

[0050] The first main pipe section and the second main pipe section are sealed with water by the first flange and the water-stopping structure;

[0051] The water injection pipe must pass through at least the first main pipe section and the first flange;

[0052] The last section of the main tube, furthest from the reinforcing ring at the top, is the second concentric tube.

[0053] The end of the main pipe in the first section is connected to the water collection and purification system; the end of the water injection pipe is connected to the water injection and pressurization system; the water collection and purification system is connected to the water injection and pressurization system.

[0054] Optionally, the injection and drainage pipe also includes an exhaust pipe and a groundwater pressure sensor;

[0055] The exhaust pipe passes through at least the first main pipe section and the first flange;

[0056] A groundwater pressure sensor is installed at the top of the exhaust pipe; an exhaust pipe valve is installed at the bottom of the exhaust pipe.

[0057] The groundwater pressure sensor is connected to the pressure control system of the water injection pressurization system;

[0058] A digital display valve is also installed at the end of the water injection pipe.

[0059] Optionally, the length of the vent pipe is set according to the inclination of the integrated vent pipe; when the integrated vent pipe is inclined upward, the vent pipe extends to the top of the main pipe; when the integrated vent pipe is horizontal or inclined downward, the vent pipe passes through the first section of the main pipe and the first flange.

[0060] Optionally, a first filter body is filled between the two concentric flower tubes of the first section;

[0061] The second section of the concentric flower tubes is filled with a second filter body between the two flower tubes.

[0062] Optionally, a joint sealant is provided between the outer surface of the main body of the first and second concentric tube sections and the gaps in the surrounding rock.

[0063] Optionally, a fixing ring is provided at the end of the water injection pipe, and the fixing ring and the inner wall of the main pipe are fixedly connected by connecting fasteners.

[0064] Optionally, it also includes a ring-shaped drain pipe and a ring-shaped water injection pipe;

[0065] The integrated injection and drainage pipes are arranged at 30° intervals along the radial direction of the tunnel, with the center of the tunnel as the origin. A total of 12 integrated injection and drainage pipes are arranged in each tunnel section.

[0066] The end of the first main pipe is connected to the ring-shaped drainage pipe; and it is also connected to the water collection and purification system through the ring-shaped drainage pipe.

[0067] The end of the water injection pipe is connected to the ring-shaped water injection pipe; the water injection pressurization system is connected to the water injection pipe through the ring-shaped water injection pipe.

[0068] Optionally, the water collection and purification system includes: a drainage pressure device, a drainage connection pipe, a water collection tank, a third filter, and a sediment treatment device;

[0069] The drainage connection pipe is connected to the ring drainage pipe and the water collection tank respectively; the water collection tank is also connected to the water injection and pressurization system through the third filter body;

[0070] The sediment treatment device is located at the bottom of the collection tank.

[0071] Optionally, the water injection pressurization system includes: a water injection tank, a water injection connection pipe, a water injection pressure device, and a pressure control system;

[0072] The water injection connection pipe is connected to both the ring-shaped water injection pipe and the water injection pool; the water injection pressure device is located at the water injection connection pipe inlet and is connected to the pressure control system.

[0073] This embodiment also provides a method for safe control of groundwater seepage in deeply buried tunnels that integrates drainage and injection, the method comprising:

[0074] Groundwater outside the reinforced concentric ring enters the first main pipe section through the first concentric flower pipe section;

[0075] Under the action of the drainage pressure device, the water enters the water collection and purification system's collection tank through the annular drainage pipe and drainage connection pipe connected to the end of the first main pipe section, and then the water enters the water injection tank of the water injection and pressurization system through the third filter body.

[0076] After the water enters the water injection pool of the water injection and pressurization system, the water is pressed into the annular water injection pipe and each water injection pipe connected to the annular water injection pipe through the water injection pressure device.

[0077] After the water enters the main pipe above the first concentric pipe through the water injection pipe, it enters the formation through the second concentric pipe under pressure.

[0078] This embodiment provides a groundwater seepage safety control system and method for deep-buried tunnels that integrates drainage and injection. It utilizes a concentric pipe section (the first section, located near the surrounding rock) to drain groundwater from the vicinity of the tunnel's outer layer, reducing the pressure head in that area and preventing collapses or sudden water inrushes during tunnel construction, thus ensuring tunnel safety. Simultaneously, the drained groundwater is purified by a water collection and purification system, then injected into an injection pipe via a pressurization system. This water is then injected into the ground at a certain depth through a second concentric pipe section located away from the reinforced layer, forming a stable groundwater seepage field with the first drainage section. This reduces the impact of tunnel drainage on the regional groundwater environment and surface water ecosystem, achieving a synergy between tunnel construction safety and ecological environmental protection. Furthermore, to address the limited space within the tunnel, this invention proposes a structure—an integrated drainage and injection pipe—that significantly improves tunnel space utilization efficiency. Compared to separate drainage and injection methods, it offers advantages such as smaller footprint, higher construction efficiency, and lower economic costs.

[0079] Example 2

[0080] This embodiment provides a groundwater seepage safety control system for a deep buried tunnel with integrated drainage and injection, as shown in Figures 1-8. It includes the tunnel body, integrated drainage and injection pipe 1, annular drainage pipe 5, annular water injection pipe 6, water collection and purification system 4-1, and water injection pressurization system 4-2.

[0081] Furthermore, the main body of the tunnel includes a reinforcing ring 2 and surrounding rock. Reinforcing ring 2 is primarily composed of concrete, anchor bolts, steel mesh, and steel supports, preventing deformation and collapse of the surrounding rock and ensuring tunnel safety. The surrounding rock mainly refers to the rock encountered during excavation during tunnel construction. The tunnel diameter is 10m, and the thickness of reinforcing ring 2 is 200cm.

[0082] Furthermore, the integrated injection and drainage pipe 1 includes a main pipe 10, a water injection pipe 14, a first filter body 17, a silicone sealing ring 19, a flange 16, an vent pipe 12, a groundwater pressure sensor 11, an vent pipe valve 15, and a digital display valve 18. The digital display valve 18 is used to control the flow rate of the water injection pipe. The vent pipe 12 is used to vent air before water injection, improving water injection efficiency. As shown in Figure 1, with the tunnel center as the origin, the integrated injection and drainage pipe 1 is arranged at 30° intervals along the radial direction of the tunnel, and a total of 12 integrated injection and drainage pipes 1 are required for each tunnel cross-section. The distance between each cross-section is closely related to the water-bearing capacity of the surrounding rock, and is generally taken as 5-10m. The water injection pipe 14 is inserted into the main pipe 10, passes through the silicone sealing ring 19 and the flange 16, injects water into the main pipe 10, and injects water into the bedrock through the second filter body 8 at the top and the concentric flower pipe 9. Groundwater in the surrounding rock outside the reinforced layer 2 is drained into the main pipe 10 through the first concentric pipe and the first filter 17. Under the obstruction of the silicone sealing ring 19 and the first flange 16, the drained water is discharged into the tunnel and enters the water collection and purification system 4-1 through the annular drainage pipe 5 and the drainage connection pipe 7.

[0083] Furthermore, the main pipe 10 is made of stainless steel, with an inner diameter of 110mm, a length of 40m, and a wall thickness of 5mm. It can withstand a water pressure head of 3MPa. Each 4m section is connected by a flange with an outer diameter of 145mm. Within 2m of the main pipe passing through the reinforcement ring, there is the first section of concentric perforated pipe, specifically a perforated perforated pipe, used for drainage to reduce the groundwater pressure outside the reinforcement ring. At the top of the main pipe 10 is a second section of concentric perforated pipe, 4m in length, specifically a perforated perforated pipe, used for water injection. The holes on the perforated perforated pipe are circular, with a diameter of 1cm, a hole spacing of 2cm, and a row spacing of 2cm.

[0084] Furthermore, the water injection pipe 14 is made of stainless steel, with an inner diameter of 56mm, a wall thickness of 5mm, a length of 4.5m, and can withstand a pressure head of 3Mpa.

[0085] Furthermore, the first filter body 17 and the second filter body 8 are made of sponge material with a pore size of 50 ppi and a thickness of 5 cm. The second filter body 8 is mainly used to filter suspended solids in the injected water to prevent clogging of the bedrock aquifer, which would reduce its water injection efficiency; while the first filter body 17 is mainly used to filter groundwater in the surrounding rock and carry out fine particles in the surrounding rock under the action of hydraulic gradient to prevent dangerous situations such as seepage deformation.

[0086] Furthermore, the vent pipe 12 is made of stainless steel, with a diameter of 2cm and a wall thickness of 3mm, and can withstand a water pressure head of 3MPa. The vent pipe 12 is mainly installed inside the water injection pipe 14 for venting air before water injection. The length of the vent pipe 14 is set according to the inclination of the integrated injection and drainage pipe 1. That is, when the integrated injection and drainage pipe 1 is inclined upward, the vent pipe 12 should extend to the top of the main pipe 10 to vent all the gas. After all the gas is vented, the vent pipe valve 15 is closed. When the integrated injection and drainage pipe 14 is horizontal or inclined downward, the vent pipe 12 should only pass through to the flange 16 outside the reinforcing ring for 5-10cm to vent all the gas. After all the gas is vented, the vent pipe valve 15 is closed.

[0087] Furthermore, to prevent the injected water from leaking out of the gap between the main pipe 10 and the surrounding rock, ethyl acetylate foam sealant 13 is injected into the gap, and the sealant length is not less than 4m.

[0088] Furthermore, the groundwater pressure sensor 11 is an automatic water pressure recorder with a range of 300m, an accuracy of 5cm, and an automatic recording frequency of 10min / time. It is located at the end of the vent pipe 12 and fixed inside the vent pipe 12, and is used to measure the groundwater pressure of the surrounding rock during water injection.

[0089] Furthermore, to secure the main body pipe 10 and the water injection pipe 14, a 70mm diameter fixing ring 21 is added to the end of the main body pipe 10. The fixing ring 21 and the inner wall of the main body pipe 10 are connected by stainless steel connecting fasteners 20, which are welded together. A total of four stainless steel connecting fasteners 20 are provided, evenly distributed at 90° intervals between the inner wall of the main body pipe 10 and the fixing ring 21. Rubber rings 22 are directly provided between the fixing ring 21 and the water injection pipe 14.

[0090] Furthermore, the material of the annular drain pipe 5 is stainless steel pipe with a diameter of 10cm and a thickness of 5mm. A tee is reserved near the end of each main pipe 10, and the end of the main pipe 10 is fixed and sealed to the annular drain pipe 5 by welding.

[0091] Furthermore, the material of the annular water injection pipe 6 is stainless steel pipe with a diameter of 10cm and a thickness of 5mm, which can withstand a water head pressure of 3Mpa. A tee is reserved near the end of each water injection pipe 14, and the end of the water injection pipe 14 is fixed and sealed to the annular water injection pipe 6 by welding.

[0092] Furthermore, the water collection and purification system 4-1 includes an overflow pipe 23, an overflow valve 24, a drainage connection pipe 7, a water collection tank 25, a perforated plate 26, a third filter body 30, a drainage valve 31, a drainage pump 32, a sand discharge valve 33, a sludge pump 34, and a sand discharge pipe 35. The water collection tank 25 is primarily made of stainless steel, with dimensions of 5m long, 3m wide, and 3m high, and a thickness of 5mm. It can withstand a 3m high water head pressure, and one side is connected to the water injection tank 27 via the perforated plate 26 and the third filter body 30. The third filter body 30 rests on a cement base 36. The perforated plate 26 has 1cm and 2cm pores, with a row spacing of 2cm. The third filter body 30 is made of sponge material with a pore size of 80ppi and a thickness of 10cm, used to filter suspended fine particles in the water collection tank 25, providing clean water to the water injection tank 27. The drainage connection pipe 7 is made of PVC material, has a diameter of 10cm, and includes a drainage valve 31. The sand discharge pipe 35 is made of PVC and has a diameter of 10cm. It is used to discharge sediment from the collection tank. The sludge pump 34 provides power for the sludge discharge, with a power of 5kW and a head of 20m. The overflow pipe 23 is made of PVC and has a diameter of 10cm. It is equipped with an overflow valve 24.

[0093] Furthermore, the water injection pressurization system 4-2 includes a water injection tank 27, a water injection connecting pipe 29, a high-lift pressure pump 37, a water injection valve 38, and a pressure control system 28. The water injection tank 27 is primarily made of stainless steel, with dimensions of 3m long, 2m wide, and 3m high, and a thickness of 5mm. It can withstand a 3m high head pressure, and one side is connected to the collection tank 25 via a perforated plate 26 and a third filter 30. The water injection connecting pipe 29 is also made of stainless steel, with a diameter of 5cm and a wall thickness of 5mm. It can withstand a 3MPa high head pressure and is connected to the annular water injection pipe 6. The high-lift pressure pump 37 has a head of 200m and a maximum flow rate greater than 10m³ / h. 3 The system can provide high-pressure water supply to multiple injection pipes 14 at a rate of / h. The flow rate injected into each injection pipe 14 is controlled by the injection valve 38, and its flow rate is 70%-90% of the drainage flow rate corresponding to the integrated injection and drainage pipe 1. Only when the flow rate of the injection pipe 14 is less than the drainage flow rate corresponding to the integrated injection and drainage pipe 1 can the injection and drainage reach equilibrium, and the groundwater seepage field reach stability. Therefore, some drainage needs to be discarded, but the proportion of discarded water can be determined by repeatedly adjusting the size of the injection valve 38 until the drainage flow rate reaches stability. The pressure control system 28 is connected to the groundwater pressure sensor 11 and the high-lift pressure pump 37. Its output pressure is mainly determined by the data of the groundwater pressure sensor 11, that is, the pump output pressure is the pressure head value in the injection chamber when the injection valve 38 is closed plus 5-10m. Only when the pressure provided by the high-lift pressure pump 37 is significantly higher than the groundwater pressure value of the stratum at the injection point by a certain range can water be effectively injected into the stratum. However, the pressure head should not be increased too much, otherwise it may induce seepage safety problems.

[0094] This embodiment provides a working process for an integrated injection and drainage groundwater seepage safety control system for deep-buried tunnels, as follows:

[0095] After tunnel excavation, the surrounding loose layers are reinforced to form a relatively stable reinforced layer 2. Then, a specialized drilling rig is used to drill holes with a diameter of 120mm, and an integrated injection-discharge pipe 1 is installed in each hole. With the tunnel center as the origin, one integrated injection-discharge pipe 1 is arranged radially along the tunnel at 30° intervals, requiring a total of 12 integrated injection-discharge pipes for each tunnel section. The installation procedure for each integrated injection-discharge pipe 1 is as follows:

[0096] (1) First, install the main pipe 10 with a diameter of 110cm. The main pipe is installed in sections of 4m each, and each section is connected by a flange to ensure its airtightness. The last section of the main pipe is the second concentric pipe, with the second filter body 8 filled between the two concentric pipes, and then extended by a flange. The first section of the main pipe is the first concentric pipe at the end near the surrounding rock, with the first drainage filter body 17 filled between the two concentric pipes, while the side near the center of the tunnel is a solid pipe, connected and sealed by a flange 16 to prevent water in the water injection pipe 14 from entering the first drainage filter body 17. When installing the first section of the main pipe, the water injection pipe 14 and the vent pipe 12 should be installed at the same time, passing through the flange 16 for 0.5m, and sealed with a silicone sealing ring 19. A digital display valve 18 is installed at the end of the water injection pipe 14 (near the tunnel side) to adjust the water injection volume and rate.

[0097] (2) The installation depth of the exhaust pipe 12 is related to the inclination of the main pipe 10. When the main pipe 10 is inclined upwards, the installation depth of the exhaust pipe 12 should extend to the top of the last section of the main pipe to facilitate venting during water injection. When the main pipe 10 is horizontal or inclined downwards, the installation depth of the exhaust pipe 12 should only need to pass through the flange 16. When the main pipe 10 is horizontal, the exhaust pipe 12 should be installed at the highest position to facilitate gas discharge. The groundwater pressure sensor 11 is welded to the top of the exhaust pipe 12 and connected to the pressure control system 28 via a wire.

[0098] Each integrated drain and injection pipe 1 is connected to both the annular drain pipe 5 and the annular water injection pipe 6. Specifically, the end of the main pipe 10 is fixed and sealed to the pre-reserved T-junction on the annular drain pipe 5 by welding to prevent leakage; the end of the water injection pipe 14 is fixed and sealed to the pre-reserved T-junction on the annular water injection pipe 6 by welding to prevent leakage.

[0099] The annular drainage pipe 5 is connected to the water collection and purification system 4-1 via the drainage connection pipe 7. Groundwater from the surrounding rock outside the reinforced layer 2 enters the main pipe 10 through the first concentric pipe section and the first filter body 17, then flows through the annular water pipe 5, the drainage connection pipe 7, and the drainage pump 32 into the collection tank 25 (the drainage valve 31 should be opened first). The water then flows through the third drainage filter body 30 into the injection tank 27. Sediment deposited in the collection tank 25 is discharged through the sand discharge pipe 35 at its bottom. If the sediment content is high, the sludge pump 34 is activated for forced discharge. During non-sand discharge periods, the sand discharge valve 33 is closed to prevent water leakage. When the collection tank 25 exceeds its capacity, the overflow valve 24 can be opened, and excess drainage is discarded through the overflow pipe 23 to maintain stable drainage and injection circulation.

[0100] After the water enters the injection pool 27, it is pumped by the high-lift pump 37 along the injection connection pipe 29 into the annular injection pipe 6 and each injection pipe 14. Once inside the main pipe 10, the water, under pressure, flows through the second concentric pipe section and the second filter 8 into the formation. Before injection, the vent valve 15 on the vent pipe 12 should be opened, and closed immediately after all air is expelled from the main pipe 10. The pressure of the high-lift pump 37 is the reading of the groundwater pressure sensor 11 plus 5-10m to ensure the water can be effectively injected into the formation. The injection flow rate is adjusted by the digital display valve 18 on each injection pipe 14. Excess drainage is discharged through the overflow pipe 23 of the collection pool 27, stabilizing the drainage flow and forming a stable injection-drainage cycle.

[0101] This invention proposes a groundwater seepage safety control system and method for deep-buried tunnels that integrates drainage and water injection, addressing the conflict between existing drainage and ecological impacts from the perspectives of tunnel construction safety and ecological health. Simultaneously, this invention proposes an integrated drainage and injection pipe structure, which, compared to the separate construction of traditional injection and drainage holes, has the advantages of smaller footprint, higher construction efficiency, and lower economic cost. When tunnels traverse water-rich strata or areas with sensitive water ecology, the integrated drainage and injection groundwater seepage safety control system and method proposed in this invention can effectively solve the problems of seepage safety caused by high external water levels in the tunnel and the deterioration of the regional groundwater environment and water ecology caused by continuous drainage, filling the gap in existing tunnel water inrush treatment measures.

[0102] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A groundwater seepage safety control system for deep-buried tunnels integrating injection and drainage, characterized in that, include: The system comprises an integrated drainage and injection pipe, a water collection and purification system, and a water injection and pressurization system. The integrated drainage and injection pipe includes an injection pipe and multiple main pipe sections. The first main pipe section passes through the tunnel's reinforcement layer and connects to the surrounding rock outside the reinforcement layer. The end of the first main pipe section closest to the surrounding rock is a concentric pipe section. The end of the first main pipe section closest to the tunnel center is a solid pipe. The first and second main pipe sections are sealed together by a first flange and a water-stopping structure. The injection pipe passes through at least the first main pipe section and the first flange. The last main pipe section, with its top furthest point from the reinforcement layer, is a second concentric pipe section. The end of the first main pipe section connects to the water collection and purification system. The end of the injection pipe connects to the water injection and pressurization system. The water collection and purification system connects to the water injection and pressurization system. It also includes a ring-shaped drainage pipe and a ring-shaped injection pipe. The integrated drainage and injection pipe is arranged radially along the tunnel center at 30° intervals. Each tunnel section is equipped with 12 integrated drainage and injection pipes. The end of the first main section of each integrated drainage and injection pipe is connected to the annular drainage pipe and the water collection and purification system through the annular drainage pipe. The end of the injection pipe of each integrated drainage and injection pipe is connected to the annular injection pipe. The water injection pressurization system is connected to the injection pipe through the annular injection pipe. The water collection and purification system includes: a drainage pressure device, a drainage connecting pipe, a water collection pool, a third filter body, and a sediment treatment device. The drainage connecting pipe is connected to the annular drainage pipe and the water collection pool respectively. The water collection pool is also connected to the water injection pressurization system through the third filter body. The sediment treatment device is located at the bottom of the water collection pool. The water injection pressurization system includes: a water injection pool, a water injection connecting pipe, a water injection pressure device, and a pressure control system. The water injection connecting pipe is connected to the annular injection pipe and the water injection pool respectively. The water injection pressure device is located at the inlet of the water injection connecting pipe and is connected to the pressure control system.

2. The integrated injection and drainage groundwater seepage safety control system for deep-buried tunnels according to claim 1, characterized in that, The integrated injection and drainage pipe also includes an exhaust pipe and a groundwater pressure sensor; the exhaust pipe passes through at least the first main pipe section and the first flange; a groundwater pressure sensor is installed at the top of the exhaust pipe; an exhaust pipe valve is installed at the bottom of the exhaust pipe; the groundwater pressure sensor is connected to the pressure control system of the water injection pressurization system; and a digital display valve is also installed at the end of the water injection pipe.

3. The integrated injection and drainage groundwater seepage safety control system for deep-buried tunnels according to claim 2, characterized in that, The length of the vent pipe is set according to the inclination of the integrated vent pipe; when the integrated vent pipe is inclined upward, the vent pipe extends to the top of the main pipe; when the integrated vent pipe is horizontal or inclined downward, the vent pipe passes through the first section of the main pipe and the first flange.

4. The integrated injection and drainage groundwater seepage safety control system for deep-buried tunnels according to claim 1, characterized in that, The first concentric tube is filled with a first filter body between the two tubes; the second concentric tube is filled with a second filter body between the two tubes.

5. The integrated injection and drainage groundwater seepage safety control system for deep-buried tunnels according to claim 1, characterized in that, A sealant strip is installed between the outer surface of the main body of the first and second concentric tube sections and the gaps in the surrounding rock.

6. The integrated injection and drainage groundwater seepage safety control system for deep-buried tunnels according to claim 1, characterized in that, A fixing ring is installed at the end of the water injection pipe, and the fixing ring and the inner wall of the main pipe are fixedly connected by connecting fasteners.

7. A method for safe control of groundwater seepage in deeply buried tunnels integrating drainage and injection, characterized in that, The method is applicable to the groundwater seepage safety control system for deep-buried tunnels with integrated drainage and injection as described in claim 1. The method includes: groundwater outside the reinforced layer enters the first main pipe through the first concentric pipe; under the action of the drainage pressure device, the water enters the collection pool of the water collection and purification system through the annular drainage pipe and drainage connection pipe connected to the end of the first main pipe, and then the water enters the injection pool of the water injection and pressurization system through the third filter; after the water enters the injection pool of the water injection and pressurization system, the water is pressed into the annular injection pipe and each injection pipe connected to the annular injection pipe through the injection pressure device; after the water enters the main pipe above the first concentric pipe through the injection pipe, it enters the stratum through the second concentric pipe under pressure.

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