Mountain tunnel waterproof and drainage structure facilitating maintenance and replacement and construction method

Abstract

Disclosed in the present invention are a mountain tunnel waterproof and drainage structure facilitating maintenance and replacement and a construction method. The waterproof and drainage structure comprises a primary support, a secondary lining, a detachable drainage guiding structure, and a tunnel bottom drainage structure. A circumferential recess is reserved at a construction joint of the secondary lining, and the drainage guiding structure is centrally arranged. The drainage guiding structure comprises drain pipes, a circumferential drainage channel, a waterproof board, a thermal insulation material, and a decorative board, which are sequentially arranged from outside to inside. The bottom drainage structure comprises a transverse drainage channel and a central drainage channel. According to the tunnel waterproof and drainage structure, drain pipes are utilized to proactively reduce groundwater level, substantially removing groundwater behind the tunnel lining, thereby avoiding groundwater action on the supporting structure and reducing groundwater infiltration into the supporting structure. The structure features a simple construction method and easy control of construction quality. During tunnel operation and maintenance, the structure facilitates dredging, maintenance, and replacement, contributing to improved tunnel durability.

Description

A drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace, and its construction method Technical Field

[0001] This invention belongs to the field of tunnel waterproofing and drainage technology, specifically a waterproofing and drainage structure and construction method for mountain tunnels that is easy to maintain and replace. Background Technology

[0002] According to incomplete statistics, approximately one-third of existing tunnels suffer from varying degrees of water leakage, such as seepage in the tunnel arch, arch waist, arch foot, and sidewalls, as well as road surface seepage. This affects the service life of the lining structure, leading to premature damage to the tunnel surface, or compromising traffic safety, causing electrical leakage and corrosion in electromechanical monitoring equipment. Particularly in tunnels located in high-altitude, seasonally frozen soil regions, water leakage in the lining structure results in frost damage problems such as ice formation on tunnel walls, lining spalling and falling off, and water overflowing and freezing on the road surface, severely impacting vehicle traffic and driving safety. The main cause of these tunnel leakage and frost damage problems is the unreasonable design of existing drainage and waterproofing structures, failing to fully consider the impact of construction, resulting in substandard drainage and waterproofing construction quality. Currently, various tunnel defects caused by unreasonable tunnel drainage and waterproofing design have become a major intractable problem in tunnel engineering construction and a global challenge.

[0003] To address the drainage and waterproofing issues in mountain highway tunnels, countries worldwide have developed relatively systematic tunnel drainage and waterproofing structures after years of research. However, in practice, the problems have not been fundamentally and effectively solved, leading to continuously increasing project costs and more complex construction procedures and processes. Chinese Patent CN116241323A discloses a drainage and waterproofing structure for highly water-rich karst tunnels, comprising initial support, a permeable steel frame, a waterproof membrane, secondary lining, permeable corner walls, lateral drainage ditches, transverse drainage pipes, and a central drainage ditch. Chinese Patent CN114151131A discloses a tunnel drainage system and construction method suitable for highly water-rich strata, comprising initial support, secondary lining, an annular diversion channel structure, drainage holes, a waterproof membrane, sidewall sump wells, transverse buried trenches, and a central drainage ditch. These drainage and waterproofing structures all employ continuously arranged waterproof membranes to prevent groundwater from entering the tunnel interior. On the outside of the waterproof lining, permeable steel frames and annular guide channels are used to set up circumferential drainage channels. This collects groundwater from outside the waterproof lining into the drainage system and directs it to the tunnel corners. From there, it is collected into the central drainage ditch via transverse drainage pipes, thus draining the groundwater out of the tunnel. Chinese patent CN219809048U discloses a drainage structure for the secondary lining of a sandy dolomite tunnel, using circumferentially arranged drainage pipes to reduce water pressure behind the lining. Chinese patent CN113090327A discloses a multi-directional drainage system and construction method after tunnel lining, also using drainage pipes at the arch foot to reduce water pressure behind the lining of water-rich tunnels. Both are measures taken to reduce excessive water pressure exerted on the tunnel structure by groundwater after the application of a waterproof layer. Among the above four drainage structures, the use of a continuous waterproof layer is a crucial measure to ensure the tunnel's drainage structure. The quality of the waterproof layer's construction is a critical indicator of whether the tunnel will leak during later operation, posing a significant challenge to tunnel construction. Meanwhile, these drainage and waterproofing structures contain steel structures susceptible to corrosion from flowing water, such as permeable steel frames and annular diversion channels. Furthermore, all drainage pipes and ditches are designed behind the secondary lining, making them concealed works. After tunnel construction is completed, the construction quality of the drainage and waterproofing system cannot be effectively assessed. Moreover, because the pipes and ditches are located inside the structure, it is difficult to dredge the tunnel's drainage and waterproofing system later, and it is also impossible to replace corroded drainage and waterproofing materials. This leads to problems such as water leakage during tunnel operation due to the failure of the drainage and waterproofing system.

[0004] Based on the above analysis of existing tunnel waterproofing and drainage structures, the main reasons for existing tunnel waterproofing and drainage problems are as follows: First, construction quality is difficult to guarantee; waterproofing membranes cannot be completely waterproof along their entire length, and the sealing at overlapping joints is insufficient. Second, there is the problem of blockage in the waterproofing and drainage system. Due to mineral crystallization in groundwater and other factors, drainage channels are blocked, and the failure of the waterproofing and drainage system leads to groundwater overflowing and accumulating in the lining, causing leakage at weak points in the lining. Third, the durability of waterproofing and drainage materials cannot meet the design service life of the tunnel, and replacing existing waterproofing and drainage materials in existing tunnels is difficult, leading to the failure of the waterproofing and drainage system during tunnel operation. Fourth, the construction process is complex. Existing tunnel waterproofing membranes are designed for continuous length, and the tightness of the installation is difficult to control precisely, seriously affecting construction quality and progress. Fifth, the inspection and maintenance of the waterproofing and drainage system is difficult. Existing tunnel waterproofing and drainage systems are concealed works, mainly located inside the tunnel structure, and lack the function of inspection, maintenance, and replacement. These are all shortcomings of the existing tunnel waterproofing and drainage system. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace, as well as its construction method. Without significantly altering the existing construction schedule, the drainage and waterproofing system of the tunnel arch wall is centrally located to solve problems such as difficulty in ensuring construction quality, failure of the drainage and waterproofing system, and inability to replace drainage and waterproofing materials, thereby effectively solving the problem of tunnel water leakage.

[0006] This invention is achieved through the following technical solution:

[0007] A drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace includes a main tunnel structure, a detachable drainage and water diversion structure installed in the tunnel arch wall, and a bottom drainage structure installed inside the lower part of the main tunnel structure. The detachability of the structure ensures that maintenance personnel can maintain, inspect, and replace the drainage and waterproofing structure during later operation.

[0008] The drainage structure includes multiple drainage pipes laid on the initial support. One end of each drainage pipe is located in the surrounding rock of the tunnel, and the other end is located in a circumferential drainage ditch inside the initial support. The inner side of the circumferential drainage ditch is a waterproof membrane. The waterproof membrane is connected to the secondary lining by connecting studs and nuts set in the installation groove. The gap between the inner wall of the installation groove and the waterproof membrane is filled with rubber water-blocking material. The inner side of the waterproof membrane is filled with thermal insulation material, and a decorative panel flush with the secondary lining is installed on the surface.

[0009] The tunnel bottom drainage structure includes a central drainage pipe located at the lower end of the tunnel main structure, and the central drainage pipe is connected to the circumferential drainage ditch by a transverse drainage ditch.

[0010] The main structure of the tunnel serves to prevent groundwater from entering the tunnel area. Excess groundwater is diverted through the drainage structure and collected in the drainage structure at the bottom of the tunnel, and then discharged outside the tunnel area through the drainage structure at the bottom of the tunnel.

[0011] In the aforementioned drainage and waterproofing structure for mountain tunnels that facilitates maintenance and replacement, the main tunnel structure includes initial support and secondary lining. The concrete impermeability grade of both the initial support and secondary lining is P10 or higher. The secondary lining is a discontinuous structure along the tunnel's longitudinal direction. At the construction joint of the secondary lining, a 40cm gap is reserved along the tunnel's longitudinal direction to form a circumferential trench. Installation slots are provided on both sides of the circumferential trench. The distance between the installation slots and the initial support determines the size of the circumferential drainage trench, thus affecting its drainage capacity.

[0012] In the aforementioned drainage and waterproofing structure for mountain tunnels that facilitates maintenance and replacement, the drainage structure is located in the circumferential trench between the secondary linings. On the inner arch wall of the tunnel, the surface of the drainage structure is flush with the surface of the secondary lining. From the inner to the outer side of the tunnel, the drainage structure includes decorative panels, insulation material, waterproofing membrane, circumferential drainage trench, and drain pipes. The insulation material may be omitted depending on actual needs.

[0013] In the aforementioned drainage and waterproofing structure for mountain tunnels that facilitates maintenance and replacement, the drainage pipes are double-walled semi-perforated corrugated pipes, ensuring compatibility with the holes drilled in the initial support. The specific parameters, such as the number, length, and diameter of the drainage pipes, are determined based on the actual drainage volume. During installation, the corrugated pipes are simply placed into the drilled holes. There is no need to fill the gaps between the drainage pipes and the initial support.

[0014] In the aforementioned easily maintainable and replaceable drainage structure for mountain tunnels, the rubber water-blocking material comes in various forms, including but not limited to expandable waterproof rubber strips and water-swellable rubber blocks. This ensures the structure is watertight.

[0015] In the aforementioned drainage and waterproofing structure for mountain tunnels that facilitates maintenance and replacement, the waterproofing membrane is assembled in sections. The waterproofing membrane is fixed to the secondary lining using connecting studs and nuts installed in the mounting groove. A rubber water-stop block is installed between the waterproofing membrane and the inner wall of the mounting groove, and a rubber water-stop pad is installed between the connecting nut and the waterproofing membrane. The overlapping joints of the waterproofing membranes use the same structure. A rubber water-stop strip is installed between two waterproofing membranes. By adjusting the connecting nut, the rubber water-stop block deforms under stress to fill the gaps between the waterproofing membranes, achieving a seal between the waterproofing membrane and the secondary lining.

[0016] In the aforementioned drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace, the circumferential drainage ditch is formed by a pre-reserved circumferential closed ditch between the waterproofing membrane and the initial support; at the bottom of the main tunnel structure, the transverse drainage ditch is composed of precast concrete modules for transverse drainage ditches. The precast concrete modules for transverse drainage ditches are divided into two parts: a precast concrete bottom module and a precast concrete top module with a ditch. During installation, the precast concrete modules for transverse drainage ditches are first placed in the designated position and the entire transverse drainage ditch is connected to the circumferential drainage ditch and the central drainage ditch before the invert arch is backfilled.

[0017] In the aforementioned drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace, the insulation material should be removable.

[0018] A method for preventing and draining water in mountain tunnels is characterized by the following: groundwater in the surrounding rock enters the circumferential drainage ditch inside the initial support of the tunnel through a drainage pipe installed on the initial support, and then flows into the central drainage pipe connected to the outside of the tunnel through a transverse drainage channel, from which the groundwater is discharged to the outside of the tunnel.

[0019] A construction method for a drainage and waterproofing structure in a mountain tunnel that is easy to maintain and replace includes the following steps:

[0020]

S1

[0021] According to the tunnel design plan, the surrounding rock of the tunnel is excavated, and the initial support is carried out on the surface of the surrounding rock at an appropriate time according to the tunnel design and construction plan.

[0022] [S2] Construction of tunnel pavement and bottom drainage structure

[0023] According to the tunnel design plan, the tunnel invert arch was constructed and backfilled, and the road surface was built. After the invert arch was completed, the central drainage pipe was laid and the precast concrete modules of the transverse drainage ditch were placed according to the design requirements. After each precast component was placed in the appropriate position, the invert arch was backfilled and the tunnel road surface was built.

[0024] [S3] Tunnel Secondary Lining Construction

[0025] According to the tunnel design and construction plan, the secondary lining is constructed using a secondary lining formwork trolley. At the construction joint of the secondary lining, when constructing a secondary lining plate using the formwork trolley, it is staggered from the previous secondary lining plate by a certain distance in the longitudinal direction of the tunnel to form a 40cm circumferential groove. On both sides of the circumferential groove, waterproofing plate installation structure grooves are opened according to the specific dimensions of the waterproofing plate.

[0026] [S4] Construction of drainage structure for tunnel arch wall

[0027] A tunnel drainage structure is installed at the circumferential trench; at the bottom of the circumferential trench, i.e. the initial support surface, holes are opened and drainage pipes are inserted to prevent groundwater seepage from causing hole collapse; after the drainage pipes are installed, waterproof boards, insulation boards and decorative boards are installed.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] 1. This invention achieves detachable installation of the circumferential drainage ditch by incorporating detachable decorative panels, insulation materials, and waterproofing panels. This avoids the problem of difficult inspection associated with conventional circumferential drainage pipes, facilitating the inspection and maintenance of both circumferential and transverse drainage ditches during tunnel operation. It also facilitates the removal of various salt crystals from the system, effectively solving blockages and other problems in the tunnel's drainage and waterproofing system. Furthermore, the detachable design of the circumferential drainage ditch, compared to conventional circumferential drainage structures, allows for easier replacement of tunnel drainage and waterproofing materials, maintaining the normal operation of the drainage and waterproofing system, reducing groundwater damage to the tunnel, significantly extending the tunnel's lifespan, and ensuring normal operation within its designed service life.

[0030] 2. This invention centralizes the drainage and waterproofing system of the tunnel arch wall, avoiding the construction difficulties of traditional tunnel waterproofing layer layout along its entire length and the difficulty in controlling the tightness of the lining. This greatly reduces construction difficulty, makes it easier to achieve the impermeable requirements of the drainage and waterproofing system, and ensures the construction quality of the tunnel drainage and waterproofing system. Simultaneously, by setting up circumferential trenches at the construction joints of the tunnel secondary lining, the drainage and waterproofing structure is centrally located, effectively reducing weak points in the tunnel's waterproofing capacity, avoiding the problem of water leakage at traditional tunnel construction joints, and improving the overall waterproofing capacity of the tunnel.

[0031] 3. This invention arranges multiple drainage holes along the tunnel circumference, which facilitates maintenance personnel to detect groundwater in various parts of the tunnel during tunnel operation. This helps to understand the distribution of groundwater around the tunnel and solves the problem that traditional tunnels cannot accurately determine the groundwater situation.

[0032] 4. Compared with traditional waterproofing and drainage system construction methods, the novel waterproofing and drainage structure construction method provided by this invention centralizes and modularizes the tunnel waterproofing and drainage system, facilitating prefabricated tunnel construction, reducing the original waterproofing layer laying process, increasing construction speed, and accelerating the construction process. Simultaneously, the detachable modular construction of the tunnel waterproofing and drainage system facilitates unified management of construction quality and subsequent tunnel construction quality inspection. Attached Figure Description

[0033] Figure 1 is a three-dimensional schematic diagram of the overall drainage and waterproofing structure of a mountain tunnel in one embodiment of the present invention.

[0034] Figure 2 is a schematic diagram of the drainage and waterproofing structure of a mountain tunnel in one embodiment of the present invention.

[0035] Figure 3 is a schematic diagram of the installation of the waterproofing membrane of the drainage structure for mountain tunnels in one embodiment of the present invention.

[0036] Figure 4 is a schematic cross-sectional view of a partial installation of the waterproofing membrane of the drainage structure for a mountain tunnel according to an embodiment of the present invention.

[0037] Figure 5 is a schematic cross-sectional view of a partial overlap of the waterproofing membrane in the drainage structure of a mountain tunnel according to an embodiment of the present invention.

[0038] Figure 6 is a schematic cross-sectional view of a partial installation of the waterproofing membrane of the drainage structure for a mountain tunnel according to an embodiment of the present invention.

[0039] Figure 7 is a schematic cross-sectional view of a partial overlap of the waterproofing membrane in the drainage structure of a mountain tunnel according to an embodiment of the present invention.

[0040] Figure 8 is a schematic diagram of the precast concrete top module of the transverse drainage ditch in one embodiment of the present invention.

[0041] Figure 9 is a schematic diagram of the precast concrete bottom module of the transverse drainage ditch in one embodiment of the present invention.

[0042] Figure 10 is a flowchart of the construction process of the drainage and waterproofing structure of a mountain tunnel in one embodiment of the present invention.

[0043] The attached diagram is labeled as follows: 1-Initial support, 2-Secondary lining, 201-Step surface, 3-Drainage pipe, 4-Circumferential drainage ditch, 5-Waterproofing membrane, 6-Insulation material, 7-Decorative panel, 8-Transverse drainage ditch, 801-Precast concrete top module, 802-Precast concrete bottom module, 9-Central drainage pipe, 10-Rubber water-stopping material, 11-Installation groove, 1101-Movement gap, 12-Invert arch backfill and road surface, 13-Connecting stud, 14-Connecting nut, 15-Connecting slot, 1501-U-groove, 1502-Web plate, 1503-Flange, 16-Surrounding rock. Embodiments of the present invention

[0044] As shown in Figures 1-9, a maintenance-friendly drainage structure for mountain tunnels includes a main tunnel structure, a detachable drainage structure installed in the tunnel arch, and a bottom drainage structure located at the lower end of the main tunnel structure. Through the tunnel structure's inherent water-blocking function and the drainage structure, groundwater in the surrounding rock is quickly and effectively blocked, reducing groundwater pressure and alleviating the pressure on the main tunnel structure. Excess groundwater is then collected. The collected groundwater is discharged from the tunnel through the bottom drainage structure, reducing groundwater erosion.

[0045] The main tunnel structure includes initial support 1 and secondary lining 2. The concrete impermeability grade of initial support 1 and secondary lining 2 is P10 or higher. Secondary lining 2 is a discontinuous structure (i.e., an intermittent structure) along the longitudinal direction of the tunnel. That is to say, secondary lining 2 is interrupted at intervals along the longitudinal direction of the tunnel, and the interruption points are construction joints. At the construction joints of secondary lining 2, a 40cm gap is reserved along the longitudinal direction of the tunnel to form a circumferential groove. An installation groove 11 is provided on the side of adjacent secondary lining 2 facing the circumferential groove. The installation groove 11 is used to install the waterproof membrane 5.

[0046] As shown in Figures 4-6, the drainage structure is located in the circumferential trench between the secondary linings 2. The drainage structure includes a circumferential drainage trench 4 and multiple drainage pipes 3 arranged circumferentially along the tunnel and on the initial support 1. The area enclosed by adjacent secondary linings 2, the outer side of the waterproofing membrane 5, and the inner side of the initial support 1 constitutes the circumferential drainage trench 4. One end of the drainage pipe 3 is located in the surrounding rock of the tunnel, and the other end is located in the circumferential drainage trench 4. The circumferential drainage ditch 4 is sealed on the side closest to the tunnel interior using a waterproof membrane 5. The waterproof membrane 5 is connected to the secondary lining 2 at an installation groove 11. A rubber water-blocking material 10 is provided at the connection between the waterproof membrane 5 and the installation groove 11, filling the gap between the waterproof membrane 5 and the installation groove 11 to achieve a seal between the waterproof membrane 5 and the secondary lining 2, thereby ensuring the sealing of the inner side of the drainage ditch 4. In the circumferential ditch between adjacent secondary linings 2, insulation material 6 is provided in the inner area of ​​the waterproof membrane 5, and a decorative panel 7 flush with the inner surface of the secondary lining 2 is installed on the inner surface of the insulation material 6. From the inner to the outer side of the tunnel, the order of the components of the drainage structure is: decorative panel 7, insulation material 6, waterproof membrane 5, circumferential drainage ditch 4, and drain pipe 3. Depending on actual usage requirements, the insulation material 6 may be omitted.

[0047] More preferably, the mounting groove 11 can be configured as shown in Figures 4 and 5, where the adjacent sides of adjacent secondary linings 2 are set in a stepped form, with a preset distance between the stepped surface and the outer side of the secondary lining 2. The two ends of the waterproofing plate 5 overlap the stepped surfaces of the adjacent sides of the secondary lining 2, and the waterproofing plate 5 is connected to the stepped surface by connecting studs 13 and connecting nuts 14. The area where the waterproofing plate 5 connects to the stepped surface is filled with rubber water-blocking material 10 for sealing. The area between the adjacent sides of adjacent secondary linings 2 and between the outer side of the waterproofing plate 5 (i.e., the upper side shown in Figure 4) and the inner side of the initial support 1 serves as the circumferential drainage ditch 4. The area between the adjacent sides of adjacent secondary linings 2 and between the inner side of the waterproofing plate 5 (i.e., the lower side shown in Figure 4) is filled with thermal insulation material 6. A decorative plate 7 is set on the inner side of the thermal insulation material 6 between the adjacent sides of adjacent secondary linings 2, and the inner side of the decorative plate 7 is flush with the inner side of the secondary lining 2.

[0048] More preferably, the mounting groove 11 can be configured as shown in Figure 6, that is, a groove of a preset height is formed on the adjacent sides of the adjacent secondary lining 2 along the longitudinal direction of the tunnel, and this groove serves as the mounting groove 11. The waterproofing membrane 5 extends into the mounting groove 11 on the adjacent sides of the adjacent secondary lining 2 at both ends. Rubber water-blocking material 10 is provided between the inner side of the waterproofing membrane 5 and the inner side of the mounting groove 11, and between the outer side of the waterproofing membrane 5 and the outer side of the mounting groove 11, thereby achieving a sealed connection between the waterproofing membrane 5 and the secondary lining 2, and further achieving a sealed blockage of the inner side of the circumferential drainage ditch 4. The area between the adjacent sides of the adjacent secondary lining 2 and between the inner sides of the waterproofing membrane 5 is filled with thermal insulation material 6. A decorative plate 7 is provided on the inner side of the thermal insulation material 6 between the adjacent sides of the adjacent secondary lining 2, and the inner side of the decorative plate 7 is flush with the inner side of the secondary lining 2. Among them, the insulation material 6 can be an insulation board, with the two ends of the outer side of the insulation board resting on the inner side of the rubber water-blocking material 10 at both ends of the inner side of the waterproof board 5.

[0049] In a further preferred embodiment, the rubber water-stopping material 10 in the above scheme can be at least one of sealant, water-swellable rubber water-stopping block, and water-swellable rubber water-stopping strip, which can be selected by those skilled in the art according to the actual situation.

[0050] In a further preferred embodiment, the waterproofing membrane 5 can be a corrugated plate as shown in Figures 4 and 5, or a smooth plate as shown in Figures 6 and 7. When the waterproofing membrane 5 is a corrugated plate, the grooves of the corrugated plate are arranged along the circumferential direction of the tunnel. When the waterproofing membrane 5 is a corrugated plate, it has a certain capacity for expansion and contraction in the longitudinal direction of the tunnel. When there is relative displacement between adjacent secondary linings 2, the expansion and contraction of the waterproofing membrane 5 can reduce the stress at both ends of the waterproofing membrane 5, thereby ensuring the sealing effect between the waterproofing membrane 5 and the installation groove 11, and also ensuring the original construction joint function at this location. If the waterproofing membrane 5 is a smooth plate, and the installation groove 11 adopts the structure shown in Figure 6 (a certain gap is left between the edge of the installation groove 11 and the waterproofing membrane 5 in the longitudinal direction of the tunnel), when there is relative displacement between adjacent secondary linings 2, the waterproofing membrane 5 moves along the longitudinal direction of the tunnel within the installation groove 11, reducing the stress at both ends of the waterproofing membrane 5 and ensuring the original construction joint function at this location.

[0051] Referring to Figure 2, in this embodiment, the drainage structure at the bottom of the tunnel includes a central drainage pipe 9 and a transverse drainage ditch 8 located at the lower end of the tunnel's main structure. As shown in Figures 8 and 9, the transverse drainage ditch 8 adopts a precast concrete module for transverse drainage. The precast concrete module for transverse drainage is divided into two parts: a bottom precast concrete module 802 and a top precast concrete module 801 with a groove. The transverse drainage ditch 8 is located at the bottom of the circumferential ditch between adjacent secondary linings 2. The central drainage pipe 9 is set along the longitudinal direction of the tunnel. In this embodiment, one central drainage pipe 9 is set at the bottom of the invert backfill and road surface 12, and is located in the middle of the invert backfill and road surface 12 along the transverse direction of the tunnel (i.e., the left and right direction shown in Figure 2). Both ends of the circumferential drainage ditch 4 (i.e., the lower end of the left side and the lower end of the right side of the circumferential drainage ditch 4 in Figure 2) are connected to the central drainage pipe 9 through the transverse drainage ditch 8. In this embodiment, along the longitudinal direction of the tunnel, the overall shape of the central drainage pipe 9 after being connected to the transverse drainage ditch 8 is like a fishbone.

[0052] In addition, two central drainage pipes 9 can be set. This embodiment does not provide a drawing, but the relative positions can be referred to in Figure 2. Specifically, the two central drainage pipes 9 are respectively set at the bottom of the invert backfill and the road surface 9, and the two central drainage pipes 9 are respectively located on both sides of the invert backfill and the road surface 12 along the transverse direction of the tunnel. Taking the orientation shown in Figure 2 as an example, that is, the central drainage pipes 9 are respectively set on the left and right sides of the invert backfill and the road surface 12. One end of the circumferential drainage ditch 4 (such as the right end) is connected to the adjacent central drainage pipe 9 (i.e., the central drainage pipe 9 on the right side of the invert backfill and the road surface 12) through the transverse drainage ditch 8. The other end of the circumferential drainage ditch 4 (such as the left end) is connected to the adjacent central drainage pipe 9 (i.e., the central drainage pipe 9 on the left side of the invert backfill and the road surface 12) through the transverse drainage ditch 8. In this embodiment, the central drainage pipe 9 is installed at a relatively low depth and the required transverse drainage ditch 8 is relatively short, which can save construction and material costs. In addition, if a blockage occurs and dredging is required, construction only needs to be carried out on one side of the invert backfill and road surface 12, without the need for full excavation of the invert backfill and road surface 12, which can ensure the passage function of the tunnel to a certain extent.

[0053] In both scenarios described above, the transverse drainage ditch 8 is inclined, with the higher end of the transverse drainage ditch 8 connected to the lower end of the circumferential drainage ditch 4, and the lower end of the transverse drainage ditch 8 connected to the central drainage pipe 9. This ensures smooth drainage. Referring to Figure 3, in this embodiment, the installation of the waterproof membrane 5 should ensure the airtightness of the waterproofing structure. The waterproof membrane 5 can be assembled in sections. The joints of each section can be connected and fixed to the secondary lining 2 using connecting studs 13 and connecting nuts 14. Rubber water-stopping material 10 is placed between the waterproof membrane 5 and the mounting groove 11, and between the connecting nut 14 and the waterproof membrane 5. The overlapping joints of the waterproof membrane 5 use the same structure. Rubber water-stopping material (such as a rubber waterstop strip) is placed between two waterproof membranes 5. By adjusting the connecting nut 14, the rubber water-stopping material 10 (such as a rubber waterstop block) is deformed under force to fill the gaps between the waterproof membranes, achieving a seal between the waterproof membrane 5 and the secondary lining 2.

[0054] Additionally, referring to Figure 7, if the mounting groove 11 is configured as shown in Figure 6, and the waterproof membrane 5 adopts a segmented assembly structure, the overlapping joints of each segment of the waterproof membrane 5 can be connected by the connecting slot 15. The connecting slot 15 is H-shaped and includes a web 1502. Both ends of the web 1502 are vertically provided with flanges 1503, as shown in Figure 7. The web 1502 divides the space between the two flanges 1503 into two grooves, both of which are referred to as U-shaped grooves 1501. As shown in Figure 7, in the two adjacent waterproofing plates 5, the lower end of the upper waterproofing plate 5 is inserted into the U-shaped groove 1501 on the upper side of the web plate 1502, and the upper end of the lower waterproofing plate 5 is inserted into the U-shaped groove 1501 on the lower side of the web plate 1502. The width of the U-shaped groove 1501 (i.e., the net distance between the two flanges 1503) is slightly larger than the thickness of the waterproofing plate 5. This distance is sufficient to ensure that the waterproofing plate 5 can be inserted into the U-shaped groove 1501 and has space to fill the rubber water-stopping material 10. Those skilled in the art can specifically set the width of the U-shaped groove 1501 according to the above requirements, and the present invention does not make specific numerical limitations. After the rubber water-stopping material 10 is filled into the U-shaped groove 1501, the waterproofing plate 5 is then inserted into the U-shaped groove 1501. At this time, the rubber water-stopping material 10 will be squeezed out from the gap between the waterproofing plate 5 and the U-shaped groove, ensuring structural sealing. Afterwards, the waterproofing plate 5 achieves a seal between the waterproofing plate 5 and the secondary lining 2 through the mounting groove 11 and the rubber water-stopping material 10.

[0055] Preferably, the thermal insulation material 6 and the decorative panel 7 are detachable;

[0056] As shown in Figure 8, a construction method for a drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace specifically includes the following steps:

[0057]

S1

[0058] According to the tunnel design plan, the surrounding rock of the tunnel is excavated, and the initial support is carried out on the surface of the surrounding rock at an appropriate time according to the tunnel design and construction plan.

[0059] [S2] Construction of tunnel pavement and bottom drainage structure

[0060] According to the tunnel design plan, the tunnel invert arch is constructed, backfilled, and the road surface is built. After the invert arch is completed, the central drainage pipe 9 is laid out according to the design requirements, and precast concrete modules for the transverse drainage channels (including the top precast concrete module for the transverse drainage channel as shown in Figure 8 and the bottom precast concrete module for the transverse drainage channel as shown in Figure 9) are placed. After each precast component (i.e., the precast concrete module for the transverse drainage channel) is placed in a suitable position, it should be ensured that the transverse drainage channel 8 is connected to the central drainage pipe 9 and the circumferential drainage channel 4. The invert arch is then backfilled, and the tunnel road surface 12 is constructed. It should be noted that the precast concrete modules should ensure that the transverse drainage channel 8 retains a certain transverse slope, generally greater than or equal to 2%, to ensure that the water flow in the transverse drainage channel 8 has sufficient power to flow to the central drainage channel 9. At the bottom of the tunnel sidewall, the precast concrete modules should reserve pits for installing the waterproof membrane 5 to ensure smooth drainage and no leakage between the circumferential drainage channel 4 and the transverse drainage channel, as shown in Figures 8 and 9.

[0061] [S3] Tunnel Secondary Lining Construction

[0062] According to the tunnel design and construction plan, the secondary lining 2 is constructed using a secondary lining formwork trolley. At the construction joint of the secondary lining, when constructing a plate of secondary lining using the formwork trolley, it is staggered from the previous plate of secondary lining in the longitudinal direction of the tunnel by a certain distance, forming a 40cm circumferential groove. On both sides of the circumferential groove, installation grooves 11 should be set on the secondary lining 2. The depth of the installation groove 11 (i.e., the distance between the installation groove 11 and the inner side of the secondary lining 2) should meet the installation space of the waterproofing membrane 5, the insulation material 6, and the decorative panel 7. The width of the installation groove 11 should ensure that the connecting studs 13 and the connecting nuts 14 can work normally, or the waterproofing membrane 5 can be inserted into the installation groove 11 at both ends along the longitudinal direction of the tunnel, which is conducive to the stress of the waterproofing membrane and also serves the function of the original construction joint.

[0063] [S4] Construction of drainage structure for tunnel arch wall

[0064] A tunnel drainage structure is installed at the circumferential trench. At the bottom of the circumferential trench, i.e., on the surface of the initial support 1, holes with a diameter of Φ10-12cm are drilled along the tunnel circumference on the initial support 1. The depth of the holes is determined by the length of the drainage pipe 3. The drilled holes should fit tightly against the drainage pipe before the drainage pipe 3 is inserted. The function of the drainage pipe 3 is solely to ensure that the drainage holes are not blocked, allowing groundwater in the surrounding rock to smoothly enter the circumferential drainage trench 4 inside the initial support 1. Therefore, it is unnecessary to seal the gap between the drainage pipe 3 and the initial support 1. The drainage pipe 3 is a Φ8-10cm double-walled semi-perforated corrugated pipe, approximately 2.5-3m in length.

[0065] Next, the waterproof membrane 5 for the arch wall is installed. The waterproof membrane 5 is installed in sections from the arch top to both sides, sealing it in the mounting groove 11 and fixing it to the secondary lining 2. For the situations shown in Figures 3, 4, and 5, when installing the waterproof membrane 5, first, holes are drilled in the mounting groove 11, and connecting studs 13 are installed. The connecting studs 13 are then installed into the mounting groove 11, and rubber waterstop blocks are installed on the connecting studs 13, ensuring the connecting studs 13 penetrate the rubber waterstop blocks. The waterproof membrane 5 is placed in a suitable position, and the connecting studs 13 are passed through the mounting holes on the waterproof membrane 5. Rubber waterstop blocks are then placed on the connecting studs 13, and the connecting nuts 14 are tightened. By adjusting the connecting nuts 14, the rubber waterstop blocks 10 are deformed under stress to fill the gap between the waterproof membrane 5 and the secondary lining 2, ensuring a watertight seal. This completes the installation of the waterproof membrane. For the overlap of the waterproof membrane 5, install the rubber waterstop block onto the connecting stud 13, ensuring that the connecting stud 13 penetrates the rubber waterstop block. Place the waterproof membrane 5 located near the arch top in a suitable position, and pass the connecting stud 13 through the mounting hole on the waterproof membrane 5. Install rubber waterstop strips on the connecting stud 13 and its opposite side, ensuring that both connecting studs 13 penetrate the same rubber waterstop strip. Then, install the waterproof membrane 5 near the arch wall, sealing the two waterproof membranes 5 with the rubber waterstop strip. Install the rubber waterstop block on the connecting stud 13 and adjust the connecting nut 14. By adjusting the connecting nut 14, the rubber waterstop block deforms under force to fill the gap between the waterproof membranes, achieving a seal between the waterproof membrane 5 and the secondary lining 2.

[0066] After the waterproof board 5 is installed, install U-shaped clips on the connecting studs 13 to fix the frame of the insulation board 6 and the decorative board 7. Pass the insulation board through the U-shaped clips and install the frame. Then use tools to fix the decorative board to the frame to complete the installation of the decorative board.

[0067] During application, groundwater in the surrounding rock enters the circumferential drainage ditch 4 inside the initial support 1 through the drainage pipe 3 installed on the initial support of the tunnel, and then flows into the central drainage pipe 9 connected to the outside of the tunnel through the transverse drainage channel 8. The groundwater is then discharged to the outside of the tunnel through the central drainage pipe 9.

[0068] During tunnel operation, when maintenance or replacement of the drainage structure is required, tools can be used to remove the decorative panel 7 from the frame. Then, the frame, insulation board 6, and U-shaped clips are removed in sequence. Next, the connecting nut 14 is adjusted, and the rubber waterstop material 10 and waterproof board 5 are removed. At this point, the drain pipe 3 is exposed on the outside, allowing for unblocking. The transverse drainage ditch 8 at the bottom of the tunnel can be unblocked using a dredging tool. After maintenance, the waterproof board 5 and rubber waterstop material 10 can be replaced and reinstalled in their original positions. Then, the insulation board 6 and decorative panel 7 are reinstalled into the structure, completing the maintenance.

[0069] Referring to Figure 2, in the above-described scheme of the present invention, the “outer side” or “outer surface” of each component refers to the surface of the component facing the tunnel surrounding rock or that side; the “inner side” or “inner surface” of each component refers to the surface of the component facing the tunnel cross section interior (i.e., the space enclosed by the decorative panel 7, the invert backfill, and the road surface 12 shown in Figure 2) or that side.

[0070] The drainage structure of this invention actively drains groundwater behind the tunnel lining. Through drainage pipes arranged circumferentially along the tunnel, groundwater behind the lining is actively drained, preventing it from reaching the tunnel lining structure and thus reducing the waterproofing requirements of the tunnel lining, avoiding the need for traditional waterproofing layers. The circumferential drainage ditch 4 collects and discharges groundwater from the drainage pipes 3 into the transverse drainage ditch 8. The waterproofing plate 5 ensures the circumferential drainage ditch 4 is watertight, preventing groundwater from seeping into the tunnel interior. The insulation material 6 fills the ditch and provides insulation, preventing groundwater from freezing due to weather conditions within the circumferential drainage ditch. The decorative plate 7 decorates the drainage structure, ensuring an aesthetically pleasing driving environment inside the tunnel.

[0071] The transverse drainage ditch 8 located at the lower end of the tunnel collects the groundwater in the circumferential drainage ditch 4 into the central drainage pipe 9, and uses the central drainage pipe 9 to discharge the groundwater to outside the tunnel area.

[0072] Due to the special layout of the drainage pipe 3, groundwater in the surrounding rock is actively guided to flow into the drainage pipe 3, reducing or even avoiding the effect of groundwater on the initial support 1 and secondary lining 2 of the tunnel. At the same time, combined with the water-blocking performance of the lining itself as a safety reserve, groundwater prevention and control are achieved. The groundwater in the drainage pipe 3 is collected in the circumferential drainage ditch 4, and then concentrated in the central drainage pipe 9, which connects to the outside of the tunnel, through the transverse drainage ditch 8. The groundwater is then discharged through the central drainage pipe 9.

[0073] This invention discloses a maintenance-friendly and replaceable drainage structure and construction method for mountain tunnels. It rationally utilizes the waterproofing performance of the tunnel support structure, centrally located the drainage system in the tunnel arch wall, avoiding the need for continuous waterproofing layer installation along the entire length of the tunnel. This solves the construction problem of controlling the tightness of the waterproofing membrane during installation, reducing construction difficulty, simplifying the construction process, facilitating quality control, and easily achieving the requirement of an impermeable drainage system. Furthermore, the use of replaceable waterproofing membranes facilitates maintenance personnel in cleaning drainage channels and replacing waterproofing materials during tunnel operation, resolving issues such as drainage system blockage and the failure of drainage materials to reach the tunnel's design lifespan.

[0074] This invention fully leverages the respective roles, functions, and strengths of initial support and secondary lining, employing segmented prevention (blocking) and drainage (drainage) to ensure the support structure is safe and durable, reduces costs, simplifies procedures, combines prevention and drainage, effectively blocks water, ensures smooth drainage, facilitates inspection, facilitates dredging, and guarantees quality, thus having broad application prospects.

Claims

1. A drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace, characterized in that, It includes the main tunnel structure, the drainage structure installed in the tunnel arch wall, and the tunnel bottom drainage structure installed at the lower end of the main tunnel structure. The main structure of the tunnel includes an initial support (1) applied to the surface of the surrounding rock of the tunnel and a secondary lining (2) set inside the initial support (1). The secondary lining (2) is set as an interval structure along the longitudinal direction of the tunnel, and a circumferential drainage ditch (4) is provided between adjacent secondary linings (2) along the circumferential direction of the tunnel. The drainage structure includes multiple drainage pipes (3) laid on the initial support (1) of the tunnel. One end of the drainage pipe (3) is located in the surrounding rock of the tunnel, and the other end of the drainage pipe (3) is located in the circumferential drainage ditch (4) inside the initial support (1). The circumferential drainage ditch (4) has a waterproof plate (5) inside. The adjacent surfaces of the adjacent secondary linings (2) are provided with mounting grooves (11) for installing the waterproof plate (5). The waterproof plate (5) and the secondary lining (2) are detachably and sealed at the mounting grooves (11). The adjacent secondary linings (2) are provided with thermal insulation material (6) inside the waterproof plate (5). The inner surface of the thermal insulation material (6) is provided with a decorative plate (7) that is flush with the inner surface of the secondary lining (2) and detachable. The drainage structure at the bottom of the tunnel includes a central drainage pipe (9) and a transverse drainage ditch (8) located at the lower end of the main tunnel structure. The central drainage pipe (9) is connected to the lower end of each circumferential drainage ditch (4) by the transverse drainage ditch (8).

2. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, At the construction joint of the adjacent secondary lining (2), a gap of a preset distance is reserved along the longitudinal direction of the tunnel to form a circumferential trench; the adjacent surfaces of the adjacent secondary lining (2) are provided with the installation groove (11) on both sides of the circumferential trench. When the waterproofing membrane (5) is connected to the installation groove (11), the space enclosed by the adjacent surfaces of the adjacent secondary lining (2), the waterproofing membrane (5) and the initial support (1) serves as the circumferential drainage trench (4).

3. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 2, characterized in that, The installation groove (11) adopts the following structure: the adjacent sides of the adjacent secondary lining (2) are set in the form of steps, wherein a preset distance is left between the step surface and the outer side of the secondary lining (2); at this time, the two ends of the waterproof plate (5) are respectively attached to the step surface on the adjacent secondary lining (2), and the waterproof plate (5) and the step surface are connected by connecting studs (13) and connecting nuts (14), and the area where the waterproof plate (5) and the step surface are connected is filled with rubber water-blocking material (10) for sealing.

4. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 2, characterized in that, The installation groove (11) has the following structure: a groove of a preset height is provided on the adjacent side of the adjacent secondary lining (2) along the longitudinal direction of the tunnel, and the groove serves as the installation groove (11); at this time, the two ends of the waterproof plate (5) are respectively inserted into the installation groove (11) on the adjacent secondary lining (2). In the installation groove (11), rubber water-blocking material (10) is provided between the inner side of the waterproof plate (5) and the inner side of the installation groove (11), and between the outer side of the waterproof plate (5) and the outer side of the installation groove (11), so as to achieve a sealed connection between the waterproof plate (5) and the secondary lining (2).

5. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, The waterproof membrane (5) is made of corrugated sheet, and the grooves of the corrugated sheet are set along the circumference of the tunnel.

6. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, The waterproof membrane (5) uses a smooth panel.

7. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, In the circumferential direction of the tunnel, the waterproof membrane (5) adopts a segmented assembly structure. The connection between adjacent waterproof membranes (5) is connected by connecting studs (13) and connecting nuts (14) and sealed by rubber water-blocking material (10).

8. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, In the circumferential direction of the tunnel, the waterproof membrane (5) adopts a segmented assembly structure. The connection of adjacent waterproof membranes (5) is connected by a connecting slot (15) and sealed by a rubber water-blocking material (10). The connecting slot (15) is H-shaped. When adjacent waterproof membranes (5) are connected by the connecting slot (15), they are respectively inserted into the U-shaped grooves (1501) on both sides of the web of the connecting slot (15).

9. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, The drain pipe (3) is a double-walled half-perforated corrugated pipe with multiple water-permeable holes on its surface.

10. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, The rubber water-stopping material (10) is at least one of sealant, water-swellable rubber waterstop strip and water-swellable rubber waterstop insert.

11. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, The transverse drainage ditch (8) is inclined, with the higher end of the transverse drainage ditch (8) connected to the lower end of the circumferential drainage ditch (4), and the lower end of the transverse drainage ditch (8) connected to the central drainage pipe (9).

12. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, The central drainage pipe (9) is set along the longitudinal direction of the tunnel.

13. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 12, characterized in that, One central drainage pipe (9) is provided. The central drainage pipe (9) is located at the bottom of the invert backfill and road surface (12) and in the middle of the invert backfill and road surface (12) along the transverse direction of the tunnel. Both ends of the circumferential drainage ditch (4) are connected to the central drainage pipe (9) through the transverse drainage ditch (8).

14. The drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 12, characterized in that, Two central drainage pipes (9) are provided. The two central drainage pipes (9) are respectively located at the bottom of the invert backfill and the road surface (12). The two central drainage pipes (9) are respectively located on both sides of the invert backfill and the road surface (12) along the transverse direction of the tunnel. One end of the circumferential drainage ditch (4) is connected to the adjacent central drainage pipe (9) through the transverse drainage ditch (8). The other end of the circumferential drainage ditch (4) is connected to the adjacent central drainage pipe (9) through the transverse drainage ditch (8).

15. A drainage and waterproofing structure for mountain tunnels that is easy to maintain and replace according to claim 1, characterized in that, At the bottom of the main tunnel structure, the transverse drainage ditch (8) is composed of transverse drainage ditch precast concrete modules. The transverse drainage ditch precast concrete modules are divided into two parts: one part is the precast concrete bottom module (802), and the other part is the precast concrete top module (801) with grooves.

16. The construction method for the maintenance-friendly and replaceable drainage structure of a mountain tunnel according to any one of claims 1 to 15, characterized in that, Includes the following steps: 【S1】Tunnel Excavation and Initial Support Construction According to the tunnel design plan, the surrounding rock of the tunnel is excavated, and initial support is constructed on the surface of the surrounding rock in accordance with the tunnel design and construction plan. [S2] Construction of tunnel pavement and bottom drainage structure According to the tunnel design plan, the construction of the tunnel invert arch, the backfilling of the invert arch, and the road surface construction were carried out. After the invert arch is completed, the central drainage pipe is laid out according to the design requirements, and precast concrete modules for the transverse drainage ditch are placed; after each precast component is placed in the appropriate position, the invert arch is backfilled and the tunnel pavement is constructed. [S3] Tunnel Secondary Lining Construction According to the tunnel design and construction plan, the secondary lining is constructed using a secondary lining formwork trolley. At the construction joint of the secondary lining, when constructing a secondary lining plate using the formwork trolley, it is staggered from the previous secondary lining plate by a certain distance in the longitudinal direction of the tunnel to form a circumferential groove. On both sides of the circumferential groove, waterproofing plate installation structure grooves are opened according to the specific dimensions of the waterproofing plate. [S4] Construction of drainage structure for tunnel arch wall A tunnel drainage structure is installed at the circumferential trench; at the bottom of the circumferential trench, i.e. the initial support surface, holes are opened and drainage pipes are inserted to prevent groundwater seepage from causing hole collapse; after the drainage pipes are installed, waterproof boards, insulation boards and decorative boards are installed.

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