Tunnel underground water collecting structure, drainage fence and construction method

Abstract

The invention discloses a tunnel underground water collecting structure, a drainage fence and a construction method, and relates to the field of tunnel drainage, the tunnel underground water collecting structure comprises the underground water collecting structure and the drainage fence, the underground water collecting structure is arranged at intervals in the longitudinal direction of a tunnel, and the underground water collecting structure sequentially penetrates through a surface layer, an inverted arch filling layer, an inverted arch layer and a foundation layer of a tunnel pavement structure; the underground water collecting device is used for actively intercepting, collecting and guiding and draining underground water before the underground water enters a tunnel hole. The system has the advantages of prevention and treatment of forward movement, active risk control, no occupation of clearance, structure reuse, no power, reliability, reduction of structure disturbance, high water collection efficiency, strong water delivery capacity, blockage resistance, self-adaption of working conditions, stable operation, energy conservation, convenience in operation and maintenance and low maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of tunnel drainage technology, specifically to tunnel groundwater collection structures, drainage barriers, and construction methods. Background Technology

[0002] During tunnel operation or construction, groundwater can surge up along fissures in the surrounding rock, easily causing safety and durability problems such as arch lifting, lining cracking, steel corrosion, and slippery road surfaces. Especially in the event of a sudden water inrush, if the water cannot be drained quickly, the water hazard will evolve from "local leakage" into a systemic risk. Therefore, prevention and control of tunnel water inrush is of great significance.

[0003] Existing technological shortcomings: 1. Passive drainage lag: Traditional technologies typically employ a passive approach where water enters the tunnel and is then discharged. This approach is insufficient to promptly eliminate the hidden risks posed by water seeping up from the fissures in the surrounding rock at the bottom, and can easily lead to delayed drainage and localized damage from high water pressure.

[0004] 2. Limited space resources: Traditional drainage facilities require additional space inside the tunnel, increasing the excavation cross-section and construction risks, highlighting the contradiction with the scarcity of tunnel clearance. 3. Unreliable power dependence: In remote mountain tunnels, power supply is unstable, and electric drive systems are prone to failure during power outages or when equipment is flooded, failing to meet the requirements for high reliability and low maintenance.

[0005] Therefore, the purpose of this invention is to provide a groundwater collection and drainage structure / device that can actively intercept, collect and drain groundwater before it enters the tunnel, so that the groundwater is continuously diverted along a predetermined path, reducing the risk of water pressure, seepage and diffusion and secondary damage to the invert arch and bottom structure, and realizing the pre-emptive treatment of tunnel water inrush risk.

[0006] To address these issues, we provide tunnel groundwater collection structures, drainage barriers, and construction methods. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a tunnel groundwater collection structure, drainage fence, and construction method. This invention has the advantages of forward prevention and control, proactive risk control, no occupation of clearance space, structural reuse, reliable operation without electricity, reduced structural disturbance, high water collection efficiency, strong water conveyance capacity, adaptive operation, stable operation, energy saving, and low maintenance and repair costs.

[0008] To achieve the above objectives, the present invention employs a tunnel groundwater collection structure, comprising: The groundwater collection structure is arranged at intervals along the longitudinal direction of the tunnel. The groundwater collection structure passes through the surface layer, invert filling layer, invert layer and ground layer of the tunnel pavement structure in sequence. It is used to actively intercept, collect and drain groundwater before it enters the tunnel. A drainage fence is installed inside the tunnel. The drainage fence includes a drainage pipe, a hollow water conveying column, and a water evaporation unit. The groundwater collection structure includes an outer shell and a double-layer capillary core material. The double-layer capillary core material is disposed inside the outer shell. The outer layer of the double-layer capillary core material is a large-pore metal porous material, and the inner layer is a sintered metal filter material. The radial cross-section of the double-layer capillary core material is a meandering geometric shape. The enclosure drainage pipe is arranged longitudinally along the tunnel. The enclosure hollow water conveying column is set at the bottom of the enclosure drainage pipe and is used to connect the groundwater collection structure. The enclosure water evaporation unit includes longitudinally distributed horizontal pipes. The horizontal pipes are set on the side of the enclosure hollow water conveying column and are connected to the enclosure hollow water conveying column. The horizontal pipes are provided with porous sponge and fins. The porous sponge is attached to the bottom of the horizontal pipe, and the fins are located above the porous sponge and set on both sides of the horizontal pipe. The horizontal pipes with fins form multiple sets of evaporation ports that penetrate inside and outside.

[0009] As a further optimization of the above solution, the outer shell is made of seamless carbon steel pipe and the outer surface is treated with anti-corrosion.

[0010] As a further optimization of the above scheme, the cross section of the outer shell that passes through the surface layer has a smooth circular outer contour.

[0011] As a further optimization of the above scheme, the section of the outer shell that passes through the arch filling layer has an acute-angled octagonal outer contour, forming micro-gap channels to promote water collection.

[0012] As a further optimization of the above scheme, the cross section of the outer shell that penetrates the ground layer is a four-corner micro-arc transition outer contour.

[0013] As a further optimization of the above solution, the outer shell and the double-layer capillary core material are provided with narrow longitudinal holes. The longitudinal holes are arranged at intervals along the circumference of the outer shell and the double-layer capillary core material to form a continuous water inlet channel, and the edges of the longitudinal holes are provided with rounded corners.

[0014] As a further optimization of the above scheme, the surface of the double-layer capillary core material is engraved with micro-grooves, which are distributed along the axial direction and have a cross-sectional shape of V, U or trapezoid.

[0015] As a further optimization of the above solution, the fence water evaporation unit is provided with a water-blocking structure, which is a flap that rotates around a pivot, and the pivot is fixed to the inner wall of the horizontal tube. Low flow conditions: The water-blocking structure rests on the porous sponge under the action of gravity, without cutting off the capillary water channels, and the water evaporates through the fins. High flow rate operation: The thrust of the gushing water causes the water-blocking structure to rotate to the closed position, cutting off the evaporation unit and directing the water into the enclosure drainage pipe for external discharge.

[0016] The present invention also discloses drainage fences, including drainage fences in tunnel groundwater collection structures.

[0017] This invention also discloses a construction method for a tunnel groundwater collection structure, applicable to tunnel groundwater collection structures. The construction method includes the following steps: S1: Construction preparation and layout layout, determine the longitudinal direction and unit spacing of the drainage fence, take the installation position of the hollow water conveyance column of the fence as the layout benchmark of the groundwater collection structure, so that each groundwater collection structure and the drainage channel of the fence form a "one-to-one" connection relationship. S2: The prefabricated groundwater collection structure pile body is easy to modularly pre-assemble; the assembly and sealing of the outer shell and double-layer capillary core material are completed in the factory; S3: Confirmation of the shape and function of the zoning, segmentation and quality verification of the finished pile body, the four sections of the finished pile body II, II-II, III-III and IV-IV correspond to the surface layer, invert filling layer, invert layer and ground layer, to ensure that the shape of the different layers is correct and the orientation and length meet the design burial depth. S4: For drilling through the road surface structure layer, for newly built tunnels, before the surface layer is constructed, the drilling positions are reserved according to the positioning template; when the invert layer is poured, the holes are reserved. For the renovation of existing tunnels, without damaging the main structure, diamond core drilling is used to drill through the surface layer from top to bottom to the top surface of the invert filling layer. After drilling, the holes are cleaned, rinsed, and dried for later use. S5: "Coaxial smooth guide sleeve" through the waterproof layer. In order to reduce the scratching of the waterproof layer and reduce stress concentration during the crossing, a coaxial smooth guide sleeve is first inserted into the hole. Then, the "smooth circular outer contour" section of the upper part of the groundwater collection structure passes through the surface layer. A self-sealing transition piece is set at the waterproof layer to form a flexible seal and stress relief interface between the "groundwater collection structure and the waterproof layer". S6: Construction of gap-preserving structure for the invert arch filling layer. When the groundwater collection structure passes through the invert arch filling layer, the outer shell is an acute octagon in this section to reduce the contact area and form micro-gap channels to promote water collection. A thin-walled peelable sleeve is wrapped around the outside of the octagonal section and extracted after the filling layer has initially set, so that continuous or discrete water collection gaps and preferential seepage paths are formed around the octagonal section. S7: Anchoring and anti-uplift construction of the invert arch section. When the groundwater collection structure passes through the invert arch, the outer shell is a rough circular surface to increase the interface friction and interlocking with the reinforced concrete, resist the uplift tendency that may occur in the long structure, and at the same time maintain the circular shape to avoid stress concentration. During construction, the outer surface of this section is cleaned and fixed in position. During pouring, the key is to vibrate and compact it to avoid the formation of through pores that may lead to leakage and short circuit. S8: The "pile-driving insertion" and fissure expansion water diversion construction of the subgrade section. The subgrade is surrounding rock and does not have self-adaptive bonding ability. The groundwater collection structure adopts a "pile-driving" insertion in this layer. The outer shell has four corners with a slight arc transition at the corners. During the insertion process, it produces a "split-expansion" effect on the surrounding rock, connecting and opening the original micro-fissures to form more favorable seepage channels, while controlling excessive fracturing of the surrounding rock and reducing the risk of corner damage. The specific procedures are as follows: install the guide frame → align the hole position → use a hydraulic hammer to drive the hole in sections to the designed depth, and if necessary, use "light rotation correction + re-driving" to control the orientation and verticality. S9: Connecting interface installation: Set a connecting joint at the bottom of the hollow water conveyance column of the fence to match the water outlet of the groundwater collection structure. After sealing, install the fence drainage pipe and fence water evaporation unit to form an integrated channel of "underground interception - vertical water conveyance - longitudinal drainage and evaporation". S10: Evaporation unit filling and adaptive mechanism assembly: Porous sponge is filled in the fence water evaporation unit, and a water-blocking structure and its rotating shaft are assembled. Under low flow conditions, the water-blocking structure rests on the sponge without cutting off the capillary water channel; under high flow conditions, the water-blocking structure closes under the water thrust and guides the water into the fence drainage pipe to achieve rapid discharge. S11: Maintenance interface settings: Install inspection ports and flushing ports at appropriate locations on the fence drainage pipes, and regularly flush away mud and sand and check the condition of the sponge.

[0018] The tunnel groundwater collection structure, drainage fence, and construction method of the present invention have the following beneficial effects: 1. Prevention and control: Actively intercept and collect water from the surrounding rock fissures using groundwater collection structures, and continuously guide and drain groundwater before it enters the tunnel environment, thereby reducing the risk of water pressure and seepage diffusion to the invert arch and bottom structure from the source. 2. No space occupation and structural reuse: The groundwater drainage function is combined with the existing tunnel fence structure to form an integrated channel of "fence drainage pipe - hollow water conveyance column - fence water evaporation unit", so as to achieve continuous drainage without occupying the tunnel space. 3. Reliable without power: The system operates using physical mechanisms such as capillary force, gravity, head difference, and air evaporation, and can still maintain basic drainage capacity in remote tunnels when there is a power outage or when emergency conditions are insufficient.

[0019] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope as a result, and that the embodiments of the present invention include many changes, modifications and equivalents within the spirit and scope of the appended claims. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the existing tunnel surface drainage ditch structure; Figure 2 This is a schematic diagram of the existing underground drainage ditch structure in the tunnel. Figure 3 This is a schematic diagram of the tunnel surrounding rock fissure water structure according to the present invention; Figure 4 This is a schematic diagram of the tunnel fence structure of the present invention; Figure 5 This is a schematic diagram of the combination of drainage fence and groundwater collection structure of the present invention; Figure 6 This is a schematic diagram of the functional zoning structure of the groundwater collection structure of the present invention; Figure 7 For the present invention Figure 6 Sectional view at point II; Figure 8 For the present invention Figure 6 Sectional view at point II-II; Figure 9 For the present invention Figure 6 Sectional view at point III-III; Figure 10 For the present invention Figure 6 Cross-sectional view at section IV-IV; Figure 11 This is a schematic diagram of the outer shell and longitudinal hole structure of the present invention; Figure 12 This is a schematic diagram of the microstructure of the double-layer capillary core material of the present invention; Figure 13 This is a schematic diagram illustrating the capillary phenomenon principle of the present invention. Figure 14 This is a schematic diagram of the drainage fence structure of the present invention; Figure 15 For the present invention Figure 14 Cross-sectional view at VV; Figure 16 This is a schematic diagram showing the connection between the hollow water conveying column of the fence and the water evaporation unit of the fence according to the present invention; Figure 17 This is a schematic diagram illustrating the working principle of the water-blocking structure of the present invention; Figure 18 This is a schematic diagram of the hollow water supply column and drainage pipe structure of the fence according to the present invention.

[0021] In the diagram: 1. Tunnel; 2. Above-ground drainage ditch; 3. Ground surface; 4. Underground drainage ditch; 5. Tunnel invert; 6. Surrounding rock; 7. Natural fissure; 8. Tunnel enclosure; 9. Drainage enclosure; 10. Groundwater collection structure; 11. Outer shell; 12. Double-layer capillary core material; 13. Surface layer; 14. Invert filling layer; 15. Invert layer; 16. Subbase; 17. Longitudinal pores; 18. Micro-grooves; 19. Capillary; 20. Liquid; 21. Enclosure drainage pipe; 22. Enclosure hollow water conveyance column; 23. Enclosure water evaporation unit; 24. Fins; 25. Porous sponge; 26. Water-blocking structure; 27. Capillary water; 28. Excessive water inflow. Detailed Implementation

[0022] Please refer to the instruction manual appendix. Figure 1-18 The present invention provides a technical solution: a tunnel groundwater collection structure, a drainage fence, and a construction method.

[0023] The tunnel groundwater collection structure, drainage fence and construction method include drainage fence 9 and groundwater collection structure 10; wherein, drainage fence 9 is divided into fence drainage pipe 21, fence hollow water conveying column 22 and fence water evaporation unit 23; groundwater collection structure 10 is divided into outer shell 11 and double capillary core material 12.

[0024] refer to Figure 1 As shown, there are usually two types of drainage channels in tunnel 1. The one above the ground surface 3 is called the above-ground drainage channel 2.

[0025] The above-ground drainage ditch 2 has a delayed drainage system and is a passive drainage system. When the water volume is large or the local water collection is not smooth, the water will first accumulate on the road surface or near the above-ground drainage ditch 2, affecting vehicle adhesion and braking, increasing the safety risks of vehicle skidding and rear-end collisions, and pedestrian areas may also become slippery. It is sensitive to frost heave and icing, especially in cold regions. The water in the open ditch is more likely to freeze when exposed to the low temperature environment inside the tunnel, resulting in the occupation of the cross section, increased roughness, and reduced water carrying capacity. It may also form ice floes / ice embankments, affecting traffic and maintenance. It occupies clearance and interferes with traffic organization, encroaches on pedestrian belts or roadside space, and the installation of covers and ditch crossing structures will also increase structural complexity and affect walking comfort. It is detrimental to structural durability. Water spreads along the road surface and lining surface, and is likely to soak the side walls and areas near the invert arch for a long time, leading to increased risks of leakage diffusion, alkali-aggregate reaction / crystallization, steel corrosion, and concrete deterioration.

[0026] refer to Figure 2 As shown, the one below the surface 3 is called the underground drainage ditch 4.

[0027] While underground drainage ditch 4 can mitigate the impact of above-ground drainage ditch 2 on traffic to some extent, its prominent problem lies in disrupting and encroaching upon the stress transmission path of the tunnel pavement structure. Since underground drainage ditches are typically arranged continuously along the tunnel's longitudinal direction, they are equivalent to creating a long, narrow "weakened zone" or "cavity" within the pavement structure. This forces the stress, which should have diffused laterally and been evenly distributed to the surrounding rock on both sides, to detour around or concentrate on both sides of underground drainage ditch 4 when vehicle loads and the lining-invert arch system are transmitted to the pavement. This results in reduced stress diffusion capacity and insufficient lateral dispersion. Under these circumstances, the structures on both sides of underground drainage ditch 4 are more prone to localized stress concentration, differential settlement, and fatigue accumulation. Simultaneously, the pavement support conditions near underground drainage ditch 4 are weakened, making it susceptible to aging deformation and creep under repeated loading and groundwater softening over long periods. This can induce pavement cracking, misalignment, subsidence, and damage to trench covers, affecting tunnel operation safety and maintenance costs. These problems are particularly pronounced in weak surrounding rock, water-rich strata, or long-term seepage conditions.

[0028] From the perspective of structural safety and durability, underground drainage ditch 4 is not an ideal long-term solution. The common problem with above-ground drainage ditch 2 and underground drainage ditch 4 is that drainage is delayed and is passive. It can only be collected and discharged after the water has entered the tunnel and flowed to the ditch. It cannot intercept and guide groundwater before it enters the tunnel environment, which makes it easy to miss the risk control window.

[0029] refer to Figure 3 As shown, the surrounding rock 6 below the tunnel invert 5 at the bottom of tunnel 1 is usually not a homogeneous, complete block structure, but rather has discontinuous surfaces such as joints, bedding, and fracture zones, forming a network of natural fissures 7 of a certain scale.

[0030] Under groundwater conditions, these fracture networks exhibit significant water conductivity and connectivity, forming the main channels for groundwater seepage and transport in the surrounding rock.

[0031] When the excavation of Tunnel 1 alters the original stress field and seepage field, the surrounding rock fissures may further open or connect, causing groundwater to converge towards Tunnel 1 along the natural fissures 7 under the drive of the head difference, and preferentially seep out at the bottom of the tunnel invert 5, the weak points of the structure, or the exposed parts of the natural fissures 7, even forming a water surge.

[0032] Because natural fissures and seepage are concealed, random, and localized, relying solely on passive drainage facilities within the tunnel is often insufficient to effectively control the flow before water enters the tunnel environment. This increases the risk of water pressure, seepage diffusion, and durability degradation to the invert arch and bottom structure.

[0033] refer to Figure 4As shown, typical tunnel fences 8 are usually installed in highway tunnels to physically separate pedestrian walkways from vehicle lanes, prevent pedestrians from accidentally entering the motor vehicle lanes, and reduce the safety impact of airflow disturbances caused by high-speed vehicle traffic on pedestrians. These fences are mostly prefabricated and quick-adjustable structures, and have the characteristics of fixed placement, continuous longitudinal direction of the tunnel, easy installation and maintenance, and no significant encroachment on vehicle clearance. They belong to the "existing structural resources" that exist stably inside the tunnel for a long time.

[0034] Therefore, by combining the "tunnel groundwater collection structure, drainage fence and construction method" with typical prefabricated adjustable fences, the fences can maintain the original functions of separating people and vehicles and providing protection, while further incorporating the functions of actively intercepting, collecting and draining groundwater. This allows for the construction of a continuous collection and drainage channel along the longitudinal direction of the tunnel without expanding the excavation cross-section, cutting the road surface stress structure, or increasing the amount of clearance occupied.

[0035] refer to Figure 5 As shown, the present invention proposes a drainage fence and a groundwater collection structure; it mainly consists of a drainage fence 9 and a groundwater collection structure 10.

[0036] The groundwater collection structure 10 is responsible for collecting and transporting potential groundwater to the surface, while the drainage fence 9 evaporates the groundwater into the air; if the groundwater inflow is too large, it will be transported outside the tunnel.

[0037] Specifically, the structure of the groundwater collection structure 10 is as follows: The tunnel structure below the road surface can be roughly divided into four layers: First: Surface layer 13, which includes a top layer, a waterproof layer and a base layer arranged from top to bottom.

[0038] Modified asphalt concrete and flame-retardant asphalt are the most common surface layer materials, with good anti-slip and noise reduction properties. The waterproof layer set below the surface layer is most commonly made of polymer modified asphalt waterproof membrane, among which SBS modified asphalt waterproof membrane is the most typical and widely used. The base layer is the main load-bearing layer of the road surface, usually made of rigid cement concrete, which evenly distributes the pressure of vehicles to the lower layer.

[0039] Second: Invert arch filling layer 14, also known as leveling layer. The bottom of the tunnel is not flat after excavation, but arc-shaped. The function of the leveling layer is to fill this arc and provide a flat base for the road surface above. It is usually filled with plain concrete or rubble concrete.

[0040] Third: Invert layer 15. The invert is the bottom slab of the tunnel structure. It no longer belongs to the category of "road surface" but is part of the main structure of the tunnel. It is like the bottom of a large basin, resisting the underground squeezing force and supporting the entire tunnel ring. Invert layer 15 is made of reinforced concrete.

[0041] Fourth: Foundation layer 16. Foundation layer 16 can generally be understood as the base bearing body of the tunnel. It is mainly composed of the surrounding rock below the invert layer 15. The surrounding rock has a certain scale of natural fracture network, which has water conductivity and connectivity, and is the main channel for groundwater to seep and move in the surrounding rock.

[0042] refer to Figure 6 As shown, the groundwater collection structure 10 traverses the first to fourth layers of the structure. Based on the characteristics of different structural layers, the groundwater collection structure 10 has four different cross-sectional designs. Four cross-sectional views (II, II-II, III-III, and IV-IV) are drawn along the pile body of the groundwater collection structure 10, respectively, with reference to... Figure 7 , Figure 8 , Figure 9 and Figure 10 As shown.

[0043] refer to Figure 7 As shown, the groundwater collection structure 10 consists of an outer shell 11 and a double-layer capillary core material 12.

[0044] The outer shell 11 is made of seamless carbon steel pipe, which has the advantages of high pressure resistance, weldable sealing, impact resistance and controllable cost; the outer surface is treated with heavy anti-corrosion, using fusion bonded epoxy powder FBE coating for corrosion protection, which improves its service life in groundwater environment.

[0045] The outer layer of the double-layer capillary core material 12 is made of a large-pore metal porous material with relatively large pores, which is equivalent to a "pre-filtration + flow guiding layer". While having a certain capillary force, it can also reduce the direct entry of mud and sand into the fine pore layer and cause blockage. The inner layer of the double-layer capillary core material 12 is made of sintered metal filter material, which is not easy to age after long-term immersion in water, has compressive and shear resistance, stable pore size, and water absorption performance can also provide more capillary force through the design of pore size and porosity.

[0046] The inner and outer layers of the double-layer capillary core material 12 are both all-metal capillary cores. The double-layer capillary core material 12 and the outer shell 11 are both made of metal, which facilitates connection and fixation.

[0047] When the groundwater collection structure 10 passes through the surface layer 13, the outer surface of the shell 11 is designed as a smooth circular outline. The purpose is that the circular cross-section has continuous curvature, no sharp corners or abrupt break lines, which can effectively reduce stress disturbance and stress concentration at the structural interface, avoid the formation of local weak areas in the surface layer under repeated vehicle loads, thereby reducing the impact on the overall stress transmission and deformation coordination of the pavement structure, and reducing the probability of surface layer cracking, peeling or misalignment. At the same time, the smooth circular outer surface can reduce the risk of cutting and scratching the waterproof layer during construction, and improve the sealing synergy and durability with the waterproof layer.

[0048] Furthermore, the double-layer capillary core material 12 is designed with a meandering geometry. This meandering structure can significantly increase the effective cross-sectional perimeter and specific surface area of ​​the double-layer capillary core material 12 under limited outer diameter conditions, thereby increasing the effective interface of capillary action and the number of capillary channels, thus enhancing the capillary liquid absorption capacity. At the same time, the increased perimeter and multi-channel structure can provide a larger equivalent water flow cross-sectional area and lower flow resistance, thereby increasing the water delivery per unit time. Thus, without increasing the outer diameter of the structure and minimizing the occupation of tunnel clearance, the double-layer capillary core material 12 can achieve a stronger active groundwater absorption capacity and a higher continuous drainage efficiency, meeting the drainage needs under long-term seepage and sudden water inflow conditions.

[0049] refer to Figure 8 As shown, when the groundwater collection structure 10 passes through the inverted arch filling layer 14, the outer surface of the outer shell 11 is designed as a polygonal outer contour with eight acute angles. Compared with conventional circular or smooth outer walls, this polygonal outer contour is more likely to form point and line contact with the filling material of the inverted arch filling layer 14 when they are in contact, thereby effectively reducing the actual contact area and forming several continuous or discrete micro-gap channels around the outer shell 11. The micro-gap channels can provide additional seepage space around the outer shell 11, making it easier for groundwater to collect around the outer shell 11 and concentrate on the groundwater collection structure 10 under the drive of head difference and capillary action, thereby improving the collection efficiency of the structure for the surrounding seepage water and reducing the risk of local water blockage and poor water collection caused by the tight wrapping of the filling material.

[0050] Furthermore, the acute angles of the polygonal outer contour can form multiple preferential seepage paths in the circumferential direction, enhancing the ability of groundwater to flow from the filling layer to the collection structure, thereby improving the overall active collection effect.

[0051] refer to Figure 9As shown, when the groundwater collection structure 10 passes through the invert arch layer 15, the outer surface of the outer shell 11 is designed with a circular cross-section and a rough surface. Due to the long longitudinal length of the groundwater collection structure 10 along the tunnel, under the combined influence of groundwater buoyancy, seepage flow pressure, and the rebound of the filling layer, the structure may experience an upward displacement trend during construction and service, i.e., a so-called "bulging" effect, which affects its stability and its coordination with the surrounding structures. The invert arch layer 15 is usually a reinforced concrete structure with high overall stiffness and strong bearing capacity, which can provide more reliable constraints and anchoring conditions for the groundwater collection structure 10 passing through it. To improve the pull-out resistance and anti-slip resistance of the groundwater collection structure 10 at the invert arch layer 15, this invention designs the outer surface of the outer shell 11 to be roughened, so that the outer shell 11 and the invert arch concrete form a greater interface friction and mechanical interlocking effect, thereby improving the interface shear bearing capacity and anti-buoyancy stability, and reducing the risk of displacement, loosening, and sealing failure caused by buoyancy or disturbance of long-distance structures.

[0052] Meanwhile, the outer shell 11 maintains a circular outer contour in this area to avoid the introduction of stress concentration in the reinforced concrete of the invert arch by sharp corners or folded surfaces, ensuring more uniform force transmission at the crossing points, reducing adverse local stress disturbances to the invert arch layer 15, and reducing the probability of structural damage such as cracking and spalling of the invert arch, thus meeting the dual requirements of "enhancing anchorage and resisting uplift" and "reducing stress concentration to protect the invert arch".

[0053] refer to Figure 10 As shown, when the groundwater collection structure 10 passes through the base layer 16, the outer surface of the outer shell 11 is designed with four corners and the four corners are slightly curved. The purpose of this design is that the base layer 16 is usually composed of surrounding rock, with natural fissures and joint surfaces developed inside. Groundwater mostly travels along the fissure network. After the outer shell 11 is provided with four corners, it can produce a certain "splitting-expansion" effect on the surrounding rock during the insertion process, causing the original micro-fissures to open or connect under the action of local stress, thereby forming several seepage channels around the structure that are more significant than the initial fissures. This is conducive to the groundwater converging around the groundwater collection structure 10 and being captured by the double-layer capillary core material 12, thus achieving more effective active water collection.

[0054] In the context of the 16th base layer, this invention uses a "four-corner" structure instead of an "octagon" structure, and designs the corners as micro-arcs, which is mainly constrained by the dual constraints of construction procedures and surrounding rock disturbance control. First, construction process limitations: the invert arch layer 15 can have pre-reserved through holes during the concrete pouring stage, and the surface layer 13 and the invert arch filling layer 14 are usually poured or backfilled after the groundwater collection structure 10 is in place. The materials can fit and wrap the outer shell 11 to a certain extent, so the outer shell 11 can use more edges or folds to form water collection gaps in the above-mentioned layers; however, the foundation layer 16 is natural surrounding rock and does not have self-adaptive fitting ability. The groundwater collection structure 10 crossing this layer is more like a "pile driving" insertion process, which requires driving equipment to hammer or press the structure into the ground.

[0055] Second, control of surrounding rock fracturing: Too many corners will make the surrounding rock more stressed, which can easily lead to excessive fracturing of the surrounding rock and expansion of the disturbance range. This may result in local collapse, pore blockage or the formation of unstable loose areas, which is not conducive to long-term stable and controllable seepage introduction. Therefore, using fewer corners can achieve a balance between "forming water guiding channels" and "controlling surrounding rock disturbance".

[0056] Third, structural durability and construction reliability: The corners adopt a micro-arc transition instead of sharp edges, which can significantly reduce stress concentration during the driving process and reduce the risk of metal corners cracking, curling or fatigue damage when hammered, vibrated or subjected to eccentric force, thus improving the structural integrity and finished product quality stability during construction. Therefore, through the design of the four corner micro-arc outer contours, the groundwater collection structure 10 in the foundation 16 can both expand or connect the surrounding rock fissures in a controllable manner to form a seepage channel conducive to water collection, and meet the construction requirements similar to pile driving, avoiding excessive crushing of the surrounding rock and damage to the corners of the outer shell 11, thereby taking into account "water collection efficiency, construction feasibility and long-term structural reliability".

[0057] refer to Figure 11 As shown, the principle of the groundwater collection structure 10 is as follows: the outer shell 11 and the double-layer capillary core material 12 have narrow longitudinal holes 17, which are arranged at intervals in the circumferential direction to form a continuous water inlet channel; when the groundwater gathers around the groundwater collection structure 10, it can enter the internal space of the outer shell 11 through the above-mentioned longitudinal holes under the combined drive of water head difference, seepage pressure and capillary adsorption, so that the surrounding groundwater can be quickly introduced from the outside to the inside and fully contact the double-layer capillary core material 12, thereby realizing the active capture and continuous drainage of groundwater.

[0058] The longitudinal opening 17 can expand the water inlet area and improve the response speed. The longitudinal opening 17 extends along the axial direction, so that the groundwater can obtain a larger effective water inlet interface in the length direction of the structure, reduce local water inlet resistance, and increase the water inlet volume per unit time.

[0059] In addition, it avoids failure caused by local blockage. Compared with single-point or a few circular holes for water intake, the longitudinal holes 17 can form multiple points and multiple water intake paths. Even if a certain part is partially blocked due to sediment deposition, water can still continue to enter through other holes, which enhances the system's anti-clogging ability and operational reliability.

[0060] Furthermore, the longitudinal pores 17 enhance the wetting and continuous water supply of the double-layer capillary core material 12. After the groundwater enters the interior of the outer shell 11, it can form a stable wetting interface with the coarse pore guiding layer and fine pore capillary layer of the double-layer capillary core material 12, so that the capillary core material is continuously in a water supply state, thereby maintaining a stable capillary-driven water conveyance process and improving the overall drainage efficiency.

[0061] It is worth noting that the edges of the longitudinal holes 17 are rounded to reduce stress concentration and lower the risk of crack initiation during construction, insertion, and long-term vibration. The size, number, and distribution density of the longitudinal holes 17 are designed and matched according to the groundwater inflow, sand content, and required drainage capacity to achieve a balance between water collection efficiency and structural strength.

[0062] refer to Figure 12 As shown, a large number of micro-grooves 18 are engraved on the surface of the double-layer capillary core material 12. The micro-grooves 18 are distributed along the axial direction and their cross-sectional shape can be V-shaped, U-shaped or trapezoidal. The arrangement of micro-grooves 18 significantly increases the effective wetting perimeter and specific surface area of ​​the double-layer capillary core material 12, thereby increasing the contact area between the liquid and the solid interface. On the other hand, the micro-grooves themselves can form a large number of smaller capillary channels, generating a larger capillary pressure difference under the action of liquid surface tension, thereby making it easier for groundwater to be adsorbed, rise and be continuously transported along the double-layer capillary core material 12.

[0063] Therefore, without increasing the overall outer diameter of the double-layer capillary core material 12, the micro-groove 18 can effectively improve the capillary liquid absorption capacity and water supply stability, and further improve the water delivery efficiency per unit time and the overall active collection and drainage performance.

[0064] The micro-grooves 18 are prepared by processes such as mechanical etching, roll forming, laser etching or chemical etching; the width, depth, spacing and arrangement direction of the grooves can be parametrically designed according to the target capillary pressure and anti-clogging requirements, so as to achieve a balance between capillary driving capability and reliability under sand-containing water conditions.

[0065] refer to Figure 13 As shown, under conditions without external force, the liquid level in capillary 19 is significantly higher than that in liquid 20 in the cup. This phenomenon is driven by capillary pressure generated by the surface tension of the liquid and the solid-liquid wetting effect, and is usually referred to as "capillary rise" or "capillary force".

[0066] Similarly, the double-layer capillary core material 12 of the present invention has a large number of interconnected micropores and capillary channels inside, and micro grooves 18 are provided on its surface, thereby forming a high-density equivalent capillary network inside and on the surface of the material. It can continuously adsorb and transport groundwater without external power, so that groundwater can climb against gravity within a certain height range and be introduced into the groundwater collection structure 10. The principle can be understood more deeply as follows: when the liquid can wet the capillary channel wall, the liquid-gas interface forms a meniscus in the microporous groove. The curvature of the meniscus causes a pressure difference on both sides, i.e. capillary pressure.

[0067] refer to Figure 14 As shown, the drainage fence 9 consists of a fence drainage pipe 21, a fence hollow water conveying column 22, and a fence water evaporation unit 23, forming an integrated structure of "water collection-water conveyance-evaporation / drainage".

[0068] The enclosure drainage pipe 21 is installed longitudinally inside the tunnel 1. The inner surface of the enclosure drainage pipe 21 is provided with a porous sponge structure, which is used to continuously transport the collected water and guide it to the designated discharge location.

[0069] The hollow water conveyance column 22 of the fence serves as both a load-bearing component of the fence and a water conveyance riser, used to realize the vertical connection and water distribution between the groundwater collection structure 10 and the fence drainage pipe 21. The fence drainage pipe 21 and each groundwater collection structure 10 are designed to be connected in a one-to-one correspondence, that is, the outlet end of each groundwater collection structure 10 is connected to the corresponding fence drainage pipe 21 through the corresponding hollow water conveyance column 22 of the fence, so that the capillary water adsorbed and introduced by the groundwater collection structure 10 through capillary action can be further collected and transported, realizing the continuous drainage function without additional occupation of tunnel clearance, and improving the reliable drainage operation capability in remote tunnel conditions without electricity.

[0070] refer to Figure 15 As shown in the diagram, a VV cross-sectional view of the fence water evaporation unit 23 is provided. The fence water evaporation unit 23 is arranged in a near-circular or annular structure to obtain a large outer surface area within the limited fence space and facilitate integration with fence components. The fence water evaporation unit 23 includes, from bottom to top, a porous sponge 25 and fins 24 disposed above it. The fence water evaporation unit 23 includes longitudinally distributed horizontal pipes, which are disposed on the side of the hollow water supply column of the fence and connected to the hollow water supply column of the fence. The porous sponge is attached to the bottom of the horizontal pipe, and the fins are located above the porous sponge and disposed on both sides of the horizontal pipe. The positions of the fins on the horizontal pipe form multiple sets of evaporation ports that penetrate through the inside and outside.

[0071] The porous sponge 25 is used to adsorb, temporarily store and uniformly diffuse water when the groundwater inflow is small (especially when it is low-flow water transported by capillary transport through the groundwater collection structure 10), so that the water is evenly distributed along the circumference and axis of the fence water evaporation unit 23, avoiding local water accumulation or dripping only at a certain point, thereby improving the effective utilization rate of the evaporation interface and enhancing the evaporation stability.

[0072] The fins 24 are a structure that is uniformly arranged in the circumferential direction. The fins 24 can significantly increase the surface area of ​​water in contact with the tunnel air. At the same time, under the action of the tunnel ventilation airflow generated by the "vehicle wind" or "piston wind" generated by the vehicle passage, the surface air disturbance is enhanced, the convective heat transfer and mass transfer efficiency is improved, thereby accelerating the evaporation of water transported by the porous sponge 25.

[0073] Therefore, without the need for external power, the fence water evaporation unit 23 utilizes the existing airflow resources within the tunnel to achieve continuous evaporation and dissipation of small-flow groundwater, reducing the burden of centralized drainage and improving the reliability and applicability of the system in remote tunnel conditions.

[0074] refer to Figure 16 As shown, the fence water evaporation unit 23 is provided with a water-blocking structure 26. The water-blocking structure 26 is a flap that can rotate around a pivot. The water-blocking structure 26 and the porous sponge 25 cooperate to form a water-blocking-drainage mechanism based on adaptive water volume switching.

[0075] When the groundwater volume is small (i.e., only low-flow capillary water 27 continuously transferred by the groundwater collection structure 10 through capillary force), there is no visible free water inside the drainage fence 9, and the water is mainly stored in the porous sponge 25 in the form of capillary water 27. At this time, the water-blocking structure 26 hangs down naturally around the axis of rotation under the action of gravity and falls on the surface of the porous sponge 25. After the porous sponge 25 undergoes moderate deformation, it forms a stable support for the water-blocking structure 26. Since the porous sponge 25 still maintains a connected pore structure, the falling state of the water-blocking structure 26 will not cut off its internal capillary channels. The capillary water 27 can still be continuously transferred along the porous sponge 25 to the fin area 24 and evaporate, thereby ensuring that the evaporation and dissipation function under low flow conditions is not affected.

[0076] refer to Figure 17 As shown, when an excessive inrush 28 occurs, a large amount of free water appears inside the drainage fence 9. At this time, the water no longer relies mainly on capillary transport, but is driven by a large flow rate and a high head generated by the gushing of underground pressurized water.

[0077] At this time, the upward flow of water exerts a thrust on the water-blocking structure 26, causing the flap in the water-blocking structure 26 to rotate around the pivot and squeeze the porous sponge 25; as the water head increases, the water-blocking structure 26 rotates further until it reaches the closed position, thereby forming a water-blocking barrier on the fence water evaporation unit 23, preventing a large amount of water from entering the evaporation zone and causing overflow, dripping, or spillage along the fins 24, which would have adverse effects.

[0078] At the same time, under the guiding action of the closed water-blocking structure 26, the gushing water enters the fence drainage pipe 21 along the hollow water conveying column 22 of the fence, and is transported to the outside of the tunnel or the preset discharge point under the drive of gravity or water head difference, so as to achieve rapid drainage under the condition of excessive water inflow.

[0079] When the underground water inrush process ends and the water head inside the enclosure recedes, the porous sponge 25 rebounds under its own elastic restoring force, supporting the water-blocking structure 26, causing it to rotate around the axis and return to its initial state of natural gravity-induced collapse; thereafter, the system re-enters the low-flow capillary transport mode, and the capillary water in the porous sponge 25 can continue to be stably transmitted and evaporated through the fins 24, realizing the dual-mode power-free adaptive operation of "low-flow evaporation and dissipation - high-flow automatic switching and drainage".

[0080] The construction method of the tunnel groundwater collection structure, drainage fence, and construction method in this invention is as follows: Step 1: Construction preparation and layout; Based on the tunnel cross-section and the existing fence design location, determine the longitudinal direction and unit spacing of the drainage fence 9, and use the installation position of the fence hollow water conveyance column 22 as the layout benchmark for the groundwater collection structure 10, so that each groundwater collection structure 10 and the drainage channel of the fence form a "one-to-one" connection relationship, which facilitates the subsequent distribution and drainage of capillary water / rush water.

[0081] Step 2: The prefabricated groundwater collection structure 10 in the factory facilitates modular pre-assembly; the assembly and sealing of the outer shell 11 and the double-layer capillary core material 12 are completed in the factory. The outer shell is made of seamless carbon steel pipe and is heavily corrosion protected. The outer layer of the double-layer capillary core material 12 is a porous metal material with large pores, and the inner layer is a sintered metal filter material. The cross-section of the core material is designed with a meandering geometry to increase the wetting perimeter and water conveyance capacity. At the same time, longitudinal holes 17 are processed according to the design as a continuous water inlet channel.

[0082] Step 3: Confirm the shape and function of the sections, mark the finished piles in sections and check their quality. The four sections II, II-II, III-III and IV-IV correspond to the surface layer, the invert filling layer, the invert layer and the ground layer, to ensure that the shape of the different layers is correct and that the orientation and length meet the design burial depth.

[0083] Step 4: Drilling holes through the road surface structure layer. For newly built tunnels, before the surface layer 13 is constructed, the drilling positions are reserved according to the positioning template. Holes can be reserved when the invert arch layer 15 is poured. For the renovation of existing tunnels, without damaging the main structural load, diamond core drilling is used to drill through the surface layer 13 from top to bottom to the top surface of the invert arch filling layer 14. After drilling, the holes are cleaned, rinsed, and dried for later use.

[0084] Step 5: "Coaxial smooth guide sleeve" through the waterproof layer. In order to reduce the scratching of the waterproof layer and reduce stress concentration during the crossing, a coaxial smooth guide sleeve is first inserted into the hole. Then, the "smooth circular outer contour" section of the upper part of the groundwater collection structure 10 passes through the surface layer 13, and a self-sealing transition piece is set at the waterproof layer to form a flexible seal and stress relief interface between the structure and the waterproof layer.

[0085] Step 6: Construction of gap-preserving structure for section 14 of the invert arch filling layer. When the structure passes through section 14 of the invert arch filling layer, the outer shell 11 is an acute octagon in this section to reduce the contact area and form micro-gap channels to promote water collection. In order to ensure that the "micro-gap" is not completely filled by the grout during the grouting process, a peelable gap-preserving sleeve is used. A thin-walled peelable sleeve is wrapped around the outside of the octagonal section. After the filling layer has initially set, it is removed, so that continuous or discrete water collection gaps and preferential seepage paths are formed around the octagonal section, which enhances the efficiency of "peripheral convergence - longitudinal hole water inlet".

[0086] Step 7: Anchoring and anti-uplift construction of section 15 of the invert arch layer. When the structure passes through section 15 of the invert arch layer, the outer shell 11 is a rough circular surface to improve the interface friction and interlocking with the reinforced concrete, resist the possible uplift tendency of the long structure, and at the same time maintain the circular shape to avoid stress concentration. During construction, the outer surface of this section is cleaned and fixed in position. During pouring, the key is to vibrate and compact it to avoid the formation of through pores that may lead to leakage and short circuit.

[0087] Step 8: “Pile-driving insertion” and fissure expansion and water diversion construction of the 16th layer of the subgrade. The 16th layer is surrounding rock and does not have self-adaptive bonding ability. The groundwater collection structure 10 adopts a “pile-driving” insertion method in this layer. The outer shell 11 has four corners with a slight arc transition at the corners, so as to generate a “split-expansion” effect on the surrounding rock during the insertion process, connect and open the original micro-fissures to form a more favorable seepage channel, while controlling the excessive fragmentation of the surrounding rock and reducing the risk of corner damage.

[0088] The specific procedures are as follows: install the guide frame → align the hole position → use a hydraulic hammer to drive the hole in sections to the designed depth, and if necessary, use "light rotation correction + re-driving" to control the orientation and verticality.

[0089] Step 9: Connecting interface installation. Set a connecting joint (which can be welded or mechanically locked) at the bottom of the hollow water conveying column 22 of the fence to match the water outlet of the groundwater collection structure 10. After sealing, install the fence drainage pipe 21 and the fence water evaporation unit 23 to form an integrated channel of "underground interception - vertical water conveyance - longitudinal drainage and evaporation".

[0090] Step 10: Evaporation unit filling and adaptive mechanism assembly. Fill the fence water evaporation unit 23 with porous sponge 25 and assemble the water-blocking structure 26 and its rotating shaft. Under low flow conditions, the water-blocking structure rests on the sponge without cutting off the capillary water channel. Under high flow conditions, the water-blocking structure closes under the water thrust and guides the water into the fence drainage pipe 21 to achieve rapid discharge.

[0091] Step 11: Water supply and functional acceptance. Small flow acceptance: Supply water to the water inlet area of ​​the groundwater collection structure 10 and check whether the water can enter the shell through the longitudinal holes and continuously wet the double-layer capillary core material 12, and then be transported to the sponge and evaporated in the fin area. This can be confirmed by weighing / humidity changes or by observing the maintenance port. Large flow acceptance: Apply a certain water head to the bottom of the hollow water supply column 22 of the fence and verify the closure of the water blocking structure 26 and the switching of the drainage path. The water should enter the fence drainage pipe 21 and be transported to the preset discharge point outside the hole.

[0092] Step 12: Restoration and sealing. After removing the positioning template, the fence is finally fixed. The sealing transition piece at the crossing point of surface layer 13 is checked to inspect for leakage and adhesion. The flatness and load-bearing capacity of the road restoration section are retested to ensure that no new structural weak zones are introduced.

[0093] Step 13: Setting up maintenance interfaces. Inspection ports and flushing ports are set at appropriate locations on the drainage pipes 21 of the fence to facilitate regular flushing of mud and sand and inspection of the sponge condition, thereby improving long-term reliability.

Claims

1. A tunnel groundwater collection structure, characterized in that, include: The groundwater collection structure is arranged at intervals along the longitudinal direction of the tunnel. The groundwater collection structure passes through the surface layer, invert filling layer, invert layer and ground layer of the tunnel pavement structure in sequence. It is used to actively intercept, collect and drain groundwater before it enters the tunnel. A drainage fence is installed inside the tunnel. The drainage fence includes a drainage pipe, a hollow water conveying column, and a water evaporation unit. The groundwater collection structure includes an outer shell and a double-layer capillary core material. The double-layer capillary core material is disposed inside the outer shell. The outer layer of the double-layer capillary core material is a large-pore metal porous material, and the inner layer is a sintered metal filter material. The radial cross-section of the double-layer capillary core material is a meandering geometric shape. The enclosure drainage pipe is arranged longitudinally along the tunnel. The enclosure hollow water conveying column is set at the bottom of the enclosure drainage pipe and is used to connect the groundwater collection structure. The enclosure water evaporation unit includes longitudinally distributed horizontal pipes. The horizontal pipes are set on the side of the enclosure hollow water conveying column and are connected to the enclosure hollow water conveying column. The horizontal pipes are provided with porous sponge and fins. The porous sponge is attached to the bottom of the horizontal pipe, and the fins are located above the porous sponge and set on both sides of the horizontal pipe. The horizontal pipes with fins form multiple sets of evaporation ports that penetrate inside and outside.

2. The tunnel groundwater collection structure according to claim 1, characterized in that: The outer shell is made of seamless carbon steel pipe, and the outer surface is treated with anti-corrosion.

3. The tunnel groundwater collection structure according to claim 1, characterized in that: The section of the outer shell that passes through the surface layer has a smooth circular outer contour.

4. The tunnel groundwater collection structure according to claim 1, characterized in that: The section of the outer shell that passes through the inverted arch filling layer has an acute-angled octagonal outer contour, forming micro-gap channels to promote water collection.

5. The tunnel groundwater collection structure according to claim 1, characterized in that: The section of the outer shell that penetrates the ground layer has a four-cornered micro-arc transition outer contour.

6. The tunnel groundwater collection structure according to claim 1, characterized in that: Both the outer shell and the double-layer capillary core are provided with narrow longitudinal holes. The longitudinal holes are arranged at intervals along the circumference of the outer shell and the double-layer capillary core to form a continuous water inlet channel. The edges of the longitudinal holes are rounded.

7. The tunnel groundwater collection structure according to claim 1, characterized in that: The surface of the double-layer capillary core material is engraved with micro-grooves, which are distributed along the axial direction and have a cross-sectional shape of V, U or trapezoid.

8. The tunnel groundwater collection structure according to claim 1, characterized in that: The fence water evaporation unit is equipped with a water-blocking structure, which is a flap that rotates around a pivot, and the pivot is fixed to the inner wall of the horizontal tube. Low flow conditions: The water-blocking structure rests on the porous sponge under the action of gravity, without cutting off the capillary water channels, and the water evaporates through the fins; High flow rate operation: The thrust of the gushing water causes the water-blocking structure to rotate to the closed position, cutting off the evaporation unit and directing the water into the enclosure drainage pipe for external discharge.

9. A drainage fence, characterized in that: It is applied to the tunnel groundwater collection structure according to any one of claims 1-8.

10. A construction method for a tunnel groundwater collection structure, characterized in that: The construction method applicable to the tunnel groundwater collection structure according to any one of claims 1-8 includes the following steps: S1: Construction preparation and layout layout, determine the longitudinal direction and unit spacing of the drainage fence, take the installation position of the hollow water conveyance column of the fence as the layout benchmark of the groundwater collection structure, so that each groundwater collection structure and the drainage channel of the fence form a "one-to-one" connection relationship. S2: The prefabricated groundwater collection structure pile body in the factory is easy to modularly pre-assemble; the assembly and sealing of the outer shell and double-layer capillary core material are completed in the factory; S3: Confirmation of the shape and function of the zoning, segmentation and quality verification of the finished pile body, the four sections of the finished pile body II, II-II, III-III and IV-IV correspond to the surface layer, invert filling layer, invert layer and ground layer, to ensure that the shape of the different layers is correct and the orientation and length meet the design burial depth. S4: For drilling through the road surface structure layer, for newly built tunnels, before the surface layer is constructed, the drilling positions are reserved according to the positioning template; when the invert layer is poured, the holes are reserved. For the renovation of existing tunnels, without damaging the main structure, diamond core drilling is used to drill through the surface layer from top to bottom to the top surface of the invert filling layer. After drilling, the holes are cleaned, rinsed, and dried for later use. S5: "Coaxial smooth guide sleeve" that penetrates the waterproof layer. In order to reduce the scratching of the waterproof layer and reduce stress concentration during penetration, a coaxial smooth guide sleeve is first inserted into the hole. Then, the "smooth circular outer contour" section of the upper part of the groundwater collection structure penetrates the surface layer, and a self-sealing transition piece is set at the waterproof layer to form a flexible seal and stress relief interface between the "groundwater collection structure and the waterproof layer". S6: Construction of gap-preserving structure for the invert arch filling layer. When the groundwater collection structure passes through the invert arch filling layer, the outer shell is an acute octagon in this section to reduce the contact area and form micro-gap channels to promote water collection. A thin-walled peelable sleeve is wrapped around the outside of the octagonal section and extracted after the filling layer has initially set, so that continuous or discrete water collection gaps and preferential seepage paths are formed around the octagonal section. S7: Anchoring and anti-uplift construction of the invert arch section. When the groundwater collection structure passes through the invert arch, the outer shell is a rough circular surface to increase the interface friction and interlocking with the reinforced concrete, resist the uplift tendency that may occur in the long structure, and at the same time maintain the circular shape to avoid stress concentration. During construction, the outer surface of this section is cleaned and fixed in position. During pouring, the key is to vibrate and compact it to avoid the formation of through pores that may lead to leakage and short circuit. S8: "Pile-driving insertion" and fissure expansion water diversion construction in the foundation section. The foundation is surrounding rock and does not have self-adaptive bonding ability. The groundwater collection structure adopts "pile-driving" insertion in this layer. The outer shell has four corners with a slight arc transition at the corners. During the insertion process, it produces a "split-expansion" effect on the surrounding rock, connecting and opening the original micro-fissures to form more favorable seepage channels, while controlling excessive fracturing of the surrounding rock and reducing the risk of corner damage. The specific procedures are as follows: install the guide frame → align the hole position → use a hydraulic hammer to drive the hole in sections to the design depth, and use "light rotation correction + re-driving" to control the orientation and verticality; S9: Connecting interface installation: A connecting joint matching the water outlet of the groundwater collection structure is set at the bottom of the hollow water conveyance column of the fence. After sealing, the fence drainage pipe and fence water evaporation unit are installed to form an integrated channel of "underground interception - vertical water conveyance - longitudinal drainage and evaporation". S10: Evaporation unit filling and adaptive mechanism assembly: Porous sponge is filled in the fence water evaporation unit, and a water-blocking structure and its rotating shaft are assembled. Under low flow conditions, the water-blocking structure rests on the sponge without cutting off the capillary water channel; under high flow conditions, the water-blocking structure closes under the water thrust and guides the water into the fence drainage pipe to achieve rapid discharge. S11: Maintenance interface settings: Install inspection ports and flushing ports at appropriate locations on the fence drainage pipes, and regularly flush away mud and sand and check the condition of the sponge.

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