An underground tunnel deformation joint leakage water drainage structure and construction method

Abstract

The application relates to the field of underground open-cut highway tunnels, in particular to a leakage water drainage structure of a deformation joint of an underground tunnel and a construction method. The leakage water drainage structure of the deformation joint of the underground tunnel comprises a main frame formed by surrounding construction; the main frame comprises a plurality of main units poured and formed, and a deformation joint is formed between two adjacent main units; side wall ditches along the tunnel direction are formed on both sides of the tunnel bottom surface above the main frame; a water guide pipe is pre-buried on the top of the deformation joint of the tunnel bottom; a water inlet hole is formed on the water guide pipe and faces the deformation joint; and the end of the water guide pipe extends to the side wall ditch. The drainage structure can orderly discharge the leakage water of the deformation joint through the newly-added drainage pipeline and the two side ditches without obviously increasing the cost.

Description

Technical Field

[0001] This invention relates to the field of underground open-cut highway tunnels, and in particular to a drainage structure and construction method for drainage of seepage water in underground tunnel expansion joints, which is mainly used for drainage of expansion joints in underground highway tunnels. Background Technology

[0002] With urban development, underground highway tunnels are becoming increasingly common, offering significant advantages over elevated highways in terms of noise pollution and aesthetics. However, underground engineering projects place increasingly stringent requirements on tunnel waterproofing and appearance. For instance, large-scale wet leaks are not permitted during final acceptance, and linear seepage is not allowed during operation. Although modern tunnel engineering has begun to implement measures such as waterproof membranes, expansion joint drainage boxes, and sidewall drainage ditches to isolate and divert groundwater, leakage at expansion joints, especially at the base of the expansion joint, remains a serious problem.

[0003] Due to uneven settlement of the structure, inadequate protection of the roofing membrane during construction, and aging or even damage to the rubber waterstop, water leakage at expansion joints accounts for more than 50% of the total water leakage in the tunnel. This leakage seeps through the expansion joints into the concrete base layer and the asphalt concrete surface layer. When water enters the interior of the asphalt concrete pavement structure from the expansion joints, it reduces the adhesion of the asphalt. Because water has a greater adsorption force on the surface of coarse aggregates than on asphalt, prolonged immersion causes the asphalt to peel off from the aggregate surface. Combined with traffic loads, this creates water flow, which in turn causes the peeled asphalt to be washed away and carried out of the asphalt concrete surface layer. Consequently, the asphalt concrete pavement develops defects such as loosening, peeling, and potholes, reducing the service life of the asphalt concrete surface layer at the expansion joints.

[0004] Sealing expansion joints is difficult because once the rubber waterstops installed during construction are damaged, they cannot be replaced, and settlement caused by uneven geological conditions cannot be repaired. Currently, polyurethane is commonly used for sealing expansion joints. This material is organic and is easily eroded by groundwater and its own aging, resulting in low durability. It can only provide a temporary seal and cannot fundamentally solve the problem of water leakage in expansion joints. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a drainage structure and construction method for seepage water from underground tunnel expansion joints. This drainage structure can, without significantly increasing costs, orderly discharge seepage water from expansion joints through newly added drainage pipes, side ditches, etc., via a reasonable flow path.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A drainage structure for leakage at an underground tunnel expansion joint includes a main frame that encloses and forms the tunnel; the main frame includes multiple cast-in-place main units, with an expansion joint formed between adjacent main units; characterized in that: sidewall drainage ditches are constructed on both sides of the tunnel bottom above the main frame, running along the tunnel direction; a water guide pipe is pre-embedded at the top of the expansion joint at the bottom of the tunnel, with water inlet holes facing the expansion joint on the water guide pipe, and the end of the water guide pipe extends to the sidewall drainage ditches.

[0008] The present invention adopts the above-mentioned technical solution, which relates to a drainage structure for seepage water in the expansion joint of an underground tunnel. This drainage structure has a water pipe pre-embedded at the top of the expansion joint at the bottom of the tunnel. The water pipe can divert the seepage water in the expansion joint to the sidewall drainage ditch, which, along the tunnel's direction, collects the water and leads to the pumping station. This has the following beneficial effects:

[0009] 1. A small amount of water seepage at the expansion joint sidewall flows directly into the drainage hose, and is collected in the pump room along the tunnel longitudinal slope and sidewall ditch, which prevents the seepage water from overflowing onto the outer surface of the crash barrier and improves the aesthetics of the tunnel.

[0010] 2. After the seepage water at the expansion joint is diverted, the groundwater head is effectively reduced, the wet area of ​​the surrounding tunnel walls will be significantly reduced, and the cost of sealing leaks will be reduced.

[0011] 3. The leakage water in the expansion joint is effectively drained, and the leakage water will not remain in the expansion joint for a long time. The asphalt concrete pavement is in a dry environment, which extends the service life of the asphalt concrete surface layer at the expansion joint.

[0012] Preferably, the buried depth of the water guide pipe is no less than 2cm from the upper surface of the bottom concrete slab, and the expansion joint above the water guide pipe is sealed with double-fast cement. Using double-fast cement to seal the expansion joint prevents leaking water from seeping upwards.

[0013] In a further preferred embodiment, a foam rod is installed at the outer end of the expansion joint in the tunnel sidewall, with the bottom of the foam rod extending into the sidewall drainage ditch or connected to a water pipe. In this embodiment, seepage water on the tunnel sidewall is absorbed and diverted to the sidewall drainage ditch by the foam rod within the expansion joint, or diverted to the sidewall drainage ditch via the water pipe, thereby eliminating the seepage water on the tunnel sidewall. It should be noted that because the tunnel sidewall is vertically installed, the water pipe drainage is not ideal, while the absorption and permeation effect of the foam rod is better.

[0014] Preferably, the foam rod is buried at a depth of at least 2 cm from the surface of the inner wall of the main structure, and the outer end of the expansion joint on the outside of the foam rod is sealed with sealant. The sealant can prevent water absorbed by the foam rod from seeping out from the side wall.

[0015] Preferably, HDPE waterproof membrane is laid between the bottom main frame and the concrete pad below, and between the side wall main frame and the outer enclosure structure; an additional waterproof reinforcement layer is installed on the HDPE waterproof membrane near the expansion joint. The HDPE waterproof membrane provides a waterproof effect.

[0016] Preferably, an external rubber waterstop is installed on the outer wall of the main frame, laid flat on the HDPE waterproof membrane, with the inner part of the external rubber waterstop cast into the main unit on both sides of the expansion joint. The external rubber waterstop provides a second layer of waterproofing.

[0017] Preferably, the main frame is further reinforced with embedded steel-edged rubber waterstops, which are arranged around the main frame and cast at both ends between adjacent main units. These embedded steel-edged rubber waterstops provide a third layer of waterproofing.

[0018] Preferably, the two steel edges of the embedded steel-edged rubber waterstop at the bottom of the tunnel are curved upwards at an angle of 15-20°. In this design, the steel-edged rubber waterstop placed on the bottom slab should be installed in a "basin-like" configuration, with the steel edges curved horizontally at an angle of 15-20° to facilitate compaction of the bottom slab concrete.

[0019] Preferably, anti-collision side stones are constructed on both sides of the tunnel bottom above the main frame, and the sidewall drainage ditch is formed on the anti-collision side stones. In this solution, the sidewall drainage ditch is integrally formed on the anti-collision side stones, making the solution simpler.

[0020] As a preferred option, an SBS waterproof membrane, a concrete base layer, and an asphalt concrete surface layer are sequentially installed above the main frame between the two crash barriers, from bottom to top.

[0021] A construction method for a drainage structure for leakage at expansion joints in underground tunnels, characterized by the following steps:

[0022] S1. After the tunnel foundation pit inspection is completed, the concrete cushion layer is poured with a thickness of 10cm.

[0023] S2, on the completed concrete cushion layer, measurements are taken to mark the tunnel centerline, expansion joint location, side wall edge line, bottom plate height line, etc.

[0024] S3, Lay a large area of ​​HDPE waterproof membrane, and lay an additional layer of HDPE membrane at the expansion joint for reinforcement;

[0025] S4, lay external rubber waterstops along the expansion joints, and fix the side walls and above to the ground with high-strength straps;

[0026] S5, install the bottom plate reinforcement and the embedded steel edge rubber waterstop, install the construction joint and low side wall formwork, and pour the main structure bottom plate;

[0027] S6, remove the formwork of the construction joint and the low side wall, roughen the low side wall, extend the HDPE waterproof membrane of the side wall, install the side wall reinforcement, adjust the position of the embedded steel edge rubber waterstop, then install the formwork of the side wall and the upper side of the expansion joint, erect the full-span formwork, lay the top slab formwork, install the top slab reinforcement on the formwork, and pour concrete.

[0028] S7, remove the expansion joint formwork, full-span scaffolding, and internal formwork, install a 20mm thick polyethylene sheet inside the expansion joint, and pour the tunnel main structure on the other side of the expansion joint according to the above steps.

[0029] S8. Clean the expansion joints of the side walls, remove debris within 4cm of the inner wall surface, fill with foam rods, and apply sealant.

[0030] S9. Clean the expansion joint of the base plate, remove debris within 5cm of the top surface of the base plate, and fill it with pre-drilled PVC steel wire hose, leaving a spare length of not less than 80cm at each end.

[0031] S10, Install the anti-collision wall reinforcement, pass the PVC steel wire hose through the lower reinforcement of the anti-collision wall and temporarily fix it at the location of the ditch. The ditch is installed together with the anti-collision wall template using a custom template. After inspection and acceptance, pour the anti-collision wall concrete.

[0032] S11, Remove the formwork of the ditch and the crash barrier, and cut off the excess length of the PVC wire hose so that the opening of the PVC wire hose faces the ditch.

[0033] S12, flush and clean the mud and debris in the expansion joint, take care to protect the buried PVC steel wire hose, and seal the expansion joint with double fast cement.

[0034] S13 uses a flame heating method to dry the surface water stains within a 1m range on both sides of the expansion joint, and then applies non-curing rubber asphalt waterproof coating. The coating range on each side of the expansion joint is 15cm wider than that of the SBS waterproof membrane.

[0035] S14. SBS waterproof membrane is laid on the surface of the non-cured asphalt waterproof coating of the expansion joint. It is heated while being laid. In the length direction, it needs to be laid to the side of the anti-collision side stone base. In the width direction, each side should be at least 40cm away from the expansion joint.

[0036] S15, pour the tunnel concrete base layer and cure it;

[0037] S16, paving the asphalt concrete surface layer of the tunnel. Attached Figure Description

[0038] Figure 1 This is a typical cross-sectional view of a tunnel expansion joint;

[0039] Figure 2 This is a cross-sectional view (AA).

[0040] Figure 3 This is a cross-sectional view of BB.

[0041] Figure 4 This is a magnified view of node C;

[0042] The diagram is labeled as follows: 1-HDPE waterproof membrane, 2-external rubber waterstop, 3-main frame, 4-embedded steel-edged rubber waterstop, 5-φ20mm foam rod, 6-sealant, 7-anti-collision curbstone, 8-drainage pipe, 9-fast cement, 10-SBS waterproof membrane, 11-concrete base layer, 12-asphalt concrete surface layer, 13-enclosure structure, 14-20mm polyethylene board, 15-concrete cushion layer, 16-side wall drainage ditch, 31-main unit. Detailed Implementation

[0043] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0044] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, unless explicitly defined otherwise.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. Example

[0048] like Figures 1-4 As shown, this embodiment relates to a drainage structure for leakage water in an underground tunnel expansion joint, including a main frame 3 that encloses and forms the tunnel. The main frame 3 comprises multiple cast-in-place main units, with an expansion joint formed between adjacent main units. A polyethylene sheet 14 is installed within the expansion joint to separate the two main units. Sidewall drainage ditches 16 are constructed on both sides of the tunnel bottom above the main frame 3, running along the tunnel's direction. A water guide pipe 8 is pre-embedded at the top of the expansion joint at the tunnel bottom. Water inlet holes facing the expansion joint are constructed on the water guide pipe 8, specifically one φ5mm hole every 20cm, facing vertically downwards. The end of the water guide pipe 8 extends to the sidewall drainage ditches 16, and the embedment depth of the water guide pipe 8 is no less than 2cm from the upper surface of the bottom concrete slab. The expansion joint above the water guide pipe 8 is sealed with quick-setting cement 9. The use of quick-setting cement 9 to seal the expansion joint prevents leakage water from seeping upwards. The quick-setting cement 9 is applied after the steel wire hose is embedded and after the sidewall anti-collision wall and sidewall drainage ditches 16 are poured, sealing the expansion joint.

[0049] like Figure 1 and 4 As shown, anti-collision side stones 7 are constructed on both sides of the tunnel bottom above the main frame 3, and sidewall drainage ditches 16 are formed on the anti-collision side stones 7. The sidewall drainage ditches 16 are made of concrete and are cast together with the anti-collision side stones 7. The ditches are arc-shaped with a diameter of 20cm and a depth of 14cm. The drainage slope is consistent with the longitudinal slope of the tunnel.

[0050] Furthermore, above the main frame 3 between the two curb stones 7, from bottom to top, are arranged SBS waterproof membrane 10, concrete base layer 11, and asphalt concrete surface layer 12. After the SBS waterproof membrane 10 is coated with quick-setting cement 9, it is dried by heating with a torch to remove surface water stains within a 1m range on both sides of the expansion joint. Then, a non-curing rubber asphalt waterproof coating is applied to the surface, with the coating area on each side of the expansion joint being 15cm wider than the SBS waterproof membrane 10. The SBS waterproof membrane 10 is then laid on the non-curing rubber asphalt waterproof coating while being heated. The membrane is laid along the expansion joint, extending to the side of the curb stone 7 base layer in the length direction, and at least 40cm away from the expansion joint on each side in the width direction.

[0051] In a further preferred embodiment, a foam rod 5 is installed at the outer end of the expansion joint in the tunnel sidewall. The bottom of the foam rod 5 extends into the sidewall drainage ditch 16 or connects to the water guide pipe 8. In this embodiment, seepage water on the tunnel sidewall is absorbed and diverted to the sidewall drainage ditch 16 by the foam rod 5 within the expansion joint, or by the water guide pipe 8, thereby eliminating the seepage water on the tunnel sidewall. It should be noted that because the tunnel sidewall is vertically installed, the drainage by the water guide pipe 8 is not ideal, while the absorption and permeation effect by the foam rod 5 is better. The foam rod 5 is buried at a depth of not less than 2 cm from the surface of the inner wall of the main structure, and the outer end of the expansion joint outside the foam rod 5 is sealed with sealant 6. The sealant 6 prevents water absorbed by the foam rod 5 from seeping out from the sidewall.

[0052] HDPE waterproof membrane 1 is laid between the bottom main frame 3 and the concrete pad 15 below it, and between the side wall main frame 3 and the outer enclosure structure 13. HDPE waterproof membrane 1 provides a waterproof layer. HDPE waterproof membrane 1 is made of polymer material, and the joints are overlapped with polymer overlap tape. An additional waterproof reinforcement layer, also made of HDPE membrane, is installed on the HDPE waterproof membrane 1 near the expansion joint.

[0053] Furthermore, an external rubber waterstop 2 is arranged on the outer wall of the main frame 3. The external rubber waterstop 2 is laid flat on the HDPE waterproof membrane 1, and the inner part of the external rubber waterstop 2 is cast into the main unit on both sides of the expansion joint. The external rubber waterstop 2 provides a second layer of waterproofing.

[0054] Furthermore, an embedded steel-edged rubber waterstop 4 is cast inside the main frame 3. The embedded steel-edged rubber waterstop 4 is arranged around the main frame 3, with its two ends cast between adjacent main units. The embedded steel-edged rubber waterstop 4 provides a third layer of waterproofing. The embedded steel-edged rubber waterstop 4 is fixed to the center of the base slab concrete structure using temporary formwork, with its long side parallel to the expansion joint. After the concrete base slab is poured, the temporary formwork is removed. Figure 3 In the further embodiment shown, the two steel edges of the embedded steel-edged rubber waterstop 4 at the bottom of the tunnel are raised at an angle of 15-20°. In this embodiment, the steel-edged rubber waterstop placed on the bottom slab needs to be set in a "basin-like" configuration, with the steel edges raised horizontally at an angle of 15-20°, to facilitate the compaction of the bottom slab concrete.

[0055] In summary, the above-mentioned solution involves a drainage structure for leakage at the expansion joint of an underground tunnel. It includes five waterproofing layers at the tunnel bottom: HDPE waterproof membrane 1, externally applied rubber waterstop 2, embedded steel-edged rubber waterstop 4, φ21mm PVC steel wire hose, and SBS waterproof membrane 10. Furthermore, four waterproofing layers are installed at the expansion joint on the tunnel sidewall: HDPE waterproof membrane 1, externally applied rubber waterstop 2, embedded steel-edged rubber waterstop 4, and φ20mm foam rod 5.

[0056] Furthermore, the drainage structure includes a pre-embedded water pipe 8 at the top of the expansion joint at the bottom of the tunnel. The water pipe 8 diverts seepage water from the expansion joint to the sidewall drainage ditch 16, which, along the tunnel's direction, collects water and leads to the pump house. This provides several beneficial effects:

[0057] 1. A small amount of water seepage at the expansion joint sidewall flows directly into the drainage hose, and along the tunnel longitudinal slope through the sidewall ditch 16 to the pump room, preventing the seepage water from overflowing onto the outer surface of the crash barrier 7 and improving the aesthetics of the tunnel.

[0058] 2. After the seepage water at the expansion joint is diverted, the groundwater head is effectively reduced, the wet area of ​​the surrounding tunnel walls will be significantly reduced, and the cost of sealing leaks will be reduced.

[0059] 3. The leakage water in the expansion joint is effectively drained, and the leakage water will not remain in the expansion joint for a long time. The asphalt concrete pavement is in a dry environment, which extends the service life of the asphalt concrete surface layer 12 at the expansion joint.

[0060] The aforementioned solution, without significantly increasing costs, utilizes newly added drainage pipes and side ditches to systematically drain seepage water from the expansion joints through a rational flow path. On one hand, before final acceptance, this structure effectively reduces the area of ​​dampness caused by water seepage in the expansion joints and surrounding sidewalls, meeting acceptance standards and reducing the frequency and cost of leak sealing and repair. On the other hand, during the later operational period, this structure reduces the possibility of water accumulation in the concrete base layer above the expansion joints, fundamentally eliminating the impact of dynamic water from traffic loads on the surface asphalt particles, extending the service life of the tunnel's asphalt concrete pavement, and reducing maintenance costs during operation. Example

[0061] This embodiment provides a construction method for a drainage structure for leakage at the expansion joint of an underground tunnel. Specifically, it is a construction method for the drainage structure provided in Embodiment 1, and includes the following steps:

[0062] The specific implementation method is as follows:

[0063] S1, after the tunnel foundation pit inspection is completed, the concrete cushion layer 15 is poured, with a thickness of 10cm.

[0064] S2, measurements are taken on the poured concrete cushion layer 15 to mark the tunnel centerline, expansion joint location, side wall edge line, bottom plate height line, etc.

[0065] S3, lay a large area of ​​HDPE waterproof membrane 1, and lay an additional layer of HDPE membrane at the expansion joint for reinforcement.

[0066] S4, lay external rubber waterstop 2 along the expansion joint, and fix the side wall and above to the ground with high-strength straps.

[0067] S5, install the bottom slab reinforcement and the embedded steel edge rubber waterstop 4, install the construction joint and low side wall formwork, and pour the main structure bottom slab.

[0068] S6. Roughen the surface of the low side wall, extend the HDPE waterproof membrane 1 of the side wall, install the side wall reinforcement, adjust the position of the embedded steel edge rubber waterstop 4, then install the side wall and expansion joint formwork, erect the full-span formwork, lay the top slab formwork, install the top slab reinforcement on the formwork, and then pour concrete.

[0069] S7. Remove the expansion joint formwork, full-span scaffolding, and internal formwork. Install a 20mm thick polyethylene sheet inside the expansion joint. Following the steps above, pour the main tunnel structure on the other side of the expansion joint.

[0070] S8. Clean the expansion joint of the side wall, remove debris within 4cm of the inner wall surface, fill with foam rods 5, and apply sealant 6.

[0071] S9. Clean the expansion joint of the base plate, remove debris within 5cm of the top surface of the base plate, and fill it with pre-drilled PVC steel wire hose, leaving a spare length of not less than 80cm at each end.

[0072] S10, Install the anti-collision wall reinforcement, pass the PVC steel wire hose [i.e. water pipe 8] through the lower reinforcement of the anti-collision wall, and temporarily fix it at the location of the water ditch. The water ditch is installed together with the anti-collision wall template using a custom template. After inspection and acceptance, pour the anti-collision wall concrete.

[0073] S11, Remove the formwork of the ditch and the crash barrier, and cut off the excess length of the PVC steel wire hose so that the hose is directly facing the ditch.

[0074] S12, flush and clean the mud and debris in the expansion joint, taking care to protect the buried PVC steel wire hose, and seal the expansion joint with double fast cement 9.

[0075] S13 uses a flame heating method to dry the surface water stains within a 1m range on both sides of the expansion joint, and then applies a non-curing rubber asphalt waterproof coating. The coating range on each side of the expansion joint is 15cm wider than that of SBS waterproof membrane 10.

[0076] S14. Apply SBS waterproof membrane 10 to the surface of the non-cured asphalt waterproof coating at the expansion joint while heating it. The membrane should be applied to the side of the base layer of the anti-collision curbstone 7 in the length direction and at least 40cm away from the expansion joint on each side in the width direction.

[0077] S15, pour the tunnel concrete base layer 11 and cure it.

[0078] S16, paving the tunnel asphalt concrete surface layer 12.

[0079] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0080] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A drainage structure for seepage at expansion joints in underground tunnels, comprising a main frame (3) that encloses and forms the tunnel; the main frame (3) comprises multiple cast-in-place main units, with expansion joints formed between adjacent main units; characterized in that: On both sides of the tunnel bottom, a sidewall drainage ditch (16) is constructed above the main frame (3) along the tunnel direction. A water pipe (8) is pre-embedded at the top of the deformation joint at the bottom of the tunnel. A water inlet hole facing the deformation joint is constructed on the water pipe (8). The end of the water pipe (8) extends to the sidewall drainage ditch (16). A foam rod (5) is set on the outer end of the deformation joint of the tunnel sidewall. The bottom of the foam rod (5) extends into the sidewall drainage ditch (16) or is connected to the water pipe (8). The foam rod (5) is buried at a depth of not less than 2cm from the inner wall surface of the main structure. The outer end of the deformation joint outside the foam rod (5) is sealed with sealant (6).

2. The drainage structure for seepage at expansion joints in underground tunnels according to claim 1, characterized in that: The expansion joint above the water pipe (8) is sealed with double-fast cement (9).

3. The drainage structure for seepage at expansion joints in underground tunnels according to claim 1, characterized in that: HDPE waterproof membrane (1) is laid between the bottom main frame (3) and the concrete pad (15) below it, and between the side wall main frame (3) and the outer enclosure structure (13); an additional waterproof reinforcement layer is set on the HDPE waterproof membrane (1) near the expansion joint.

4. A drainage structure for seepage at expansion joints in underground tunnels according to claim 3, characterized in that: An external rubber waterstop (2) is arranged on the outer wall of the main frame (3). The external rubber waterstop (2) is laid flat on the HDPE waterproof membrane (1). The inner part of the external rubber waterstop (2) is poured into the main unit on both sides of the deformation joint.

5. A drainage structure for seepage at expansion joints in underground tunnels according to claim 1, characterized in that: The main frame (3) is also filled with a centrally embedded steel-edged rubber waterstop (4). The centrally embedded steel-edged rubber waterstop (4) is arranged around the main frame (3) and its two ends are respectively cast between two adjacent main units.

6. A drainage structure for seepage at expansion joints in underground tunnels according to claim 5, characterized in that: The angle at which the two steel edges of the embedded steel-edged rubber waterstop (4) at the bottom of the tunnel curve upward is 15-20°.

7. A drainage structure for seepage at expansion joints in underground tunnels according to claim 1, characterized in that: The tunnel bottom surface has anti-collision side stones (7) built on both sides above the main frame (3), and the side wall drainage ditch (16) is formed on the anti-collision side stones (7).

8. A drainage structure for seepage at expansion joints in underground tunnels according to claim 7, characterized in that: SBS waterproof membrane (10), concrete base layer (11) and asphalt concrete surface layer (12) are installed on the main frame (3) between the two anti-collision side stones (7) from bottom to top.

9. A construction method for a drainage structure for leakage at expansion joints in underground tunnels, characterized in that: The underground tunnel expansion joint leakage water diversion structure according to any one of claims 1-8 includes the following steps: S1, After the tunnel foundation pit inspection is completed, the concrete cushion layer (15) is poured, with a thickness of 10cm. S2, on the poured concrete cushion layer (15), measurements are taken to mark the tunnel centerline, expansion joint location, side wall edge line, and bottom plate height line; S3, lay a large area of ​​HDPE waterproof membrane (1), and lay an additional layer of HDPE membrane at the expansion joint for reinforcement; S4, lay an external rubber waterstop along the expansion joint (2), and fix the side wall and above to the ground with high-strength straps; S5, install the bottom plate reinforcement and the embedded steel edge rubber waterstop (4), install the construction joint and low side wall formwork, and pour the main structure bottom plate; S6, remove the formwork of the construction joint and the low side wall, roughen the low side wall, extend the HDPE waterproof membrane of the side wall (1), install the side wall reinforcement, adjust the position of the embedded steel edge rubber waterstop (4), then install the formwork of the side wall and the upper side of the expansion joint, erect the full-span formwork frame, lay the top plate formwork, install the top plate reinforcement on the formwork, and pour concrete. S7, remove the expansion joint formwork, full-span scaffolding, and internal formwork, install a 20mm thick polyethylene sheet inside the expansion joint, and pour the tunnel main structure on the other side of the expansion joint according to the above steps. S8. Clean the expansion joint of the side wall, remove debris within 4cm of the inner wall surface, fill with foam rod (5), and apply sealant (6). S9, clean the expansion joint of the base plate, remove debris within 5cm from the top surface of the base plate, and fill it with the pre-drilled water pipe (8), leaving a spare length of not less than 80cm at each end; S10, install the anti-collision wall reinforcement, pass the water pipe (8) through the lower reinforcement of the anti-collision wall, and temporarily fix it at the location of the water ditch. The water ditch is installed together with the anti-collision wall template using a customized template. After inspection and acceptance, pour the anti-collision wall concrete. S11, remove the formwork of the ditch and the anti-collision wall, cut off the excess length of the water pipe (8) so that the opening of the water pipe (8) is facing the ditch; S12, flush and clean the mud and debris in the expansion joint, take care to protect the buried water pipe (8), and use double fast cement (9) to seal the expansion joint; S13, use the flame heating method to dry the surface water stains within a 1m range on both sides of the expansion joint, and then apply non-curing rubber asphalt waterproof coating. The coating range on each side of the expansion joint is 15cm wider than that of SBS waterproof membrane (10). S14, SBS waterproof membrane (10) is laid on the surface of the non-cured asphalt waterproof coating of the expansion joint. It is heated and laid at the same time. In the length direction, it needs to be laid to the side of the base layer of the anti-collision side stone (7). In the width direction, each side is not less than 40cm away from the expansion joint. S15, pour the tunnel concrete base course (11) and cure it; S16, Pave the tunnel asphalt concrete surface layer (12).

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