Tunnel structure with anti-endosmosis drainage system

Abstract

The utility model discloses a tunnel structure containing anti internal water pressure drainage system, it mainly includes initial support, inverted arch, first waterproof layer, secondary lining, second waterproof layer, tertiary lining, anti internal water pressure drainage system, the second waterproof layer is all surrounded self -draining waterproof layer, and it is composed of geotextile, plastic net and waterproof board, the anti internal water pressure drainage system includes longitudinal drainage pipe set in first waterproof layer and in second waterproof layer, central longitudinal drainage ditch set in inverted arch filling layer, inspection well and transverse drainage pipe. The utility model has the ability of resisting uneven settlement of foundation, and the waterproof and drainage system can resist the water pressure in the drainage ditch, which can avoid lining crack disease and prevent groundwater from flowing into the tunnel through the waterproof and drainage system, construction joint, settlement joint and deformation joint to cause road surface water disease.

Description

Technical Field

[0001] This utility model relates to a tunnel structure with an internal water pressure-resistant drainage system, belonging to the field of tunnel and underground engineering technology. Background Technology

[0002] With the rapid development of transportation infrastructure in western China, long tunnel projects have sprung up like mushrooms after rain. However, the western region is greatly affected by topography and geomorphology, with extremely complex and unpredictable geological conditions, posing significant challenges to tunnel construction. Especially when constructing tunnels in water-rich, soft strata, even slight negligence can lead to adverse geological disasters such as collapses, mudslides, and water inrushes, seriously endangering the personal safety and property of construction workers and affecting project progress and quality. Currently, the treatment of disaster-prone areas primarily focuses on ensuring construction progress, neglecting the maintenance challenges throughout the tunnel's lifespan. For example, some tunnels constructed using mining methods in water-rich, soft strata employ measures such as curtain grouting to address mudslides and water inrushes during construction. However, after tunnel completion and operation, these tunnels are prone to lining cracking and water leakage, leading to traffic accidents within the tunnel, consuming substantial manpower and resources, requiring repeated remediation, and causing negative social impact. Furthermore, some tunnels even experience lining collapses after only a few years of operation, resulting in the entire tunnel being submerged in mud and water, causing even greater disasters and generating significant social repercussions.

[0003] Currently, the design of tunnel structures for water-rich and soft strata is basically based on the conventional tunnel support parameters, with reinforcements. It still consists of a structural mode composed of initial support, drainage facilities and secondary lining. Groundwater is introduced into the longitudinal drainage ditch under the tunnel surface through longitudinal and transverse drainage pipes. Conventional tunnel designs typically feature thinner linings and inverts, making them suitable only for tunnels with relatively strong foundation bearing capacity. However, in water-rich, soft strata with poor foundation bearing capacity, factors such as foundation settlement, groundwater pressure, and reduced surrounding rock bearing capacity can lead to increased water pressure directly acting on the lining, causing deformation, cracking, and water leakage. Furthermore, conventional tunnel drainage systems cannot withstand internal water pressure, requiring the water head in longitudinal drainage ditches to be lower than the top elevation of the ditch. If the water-resistant capacity of the surrounding rock mass decreases rapidly, excessive water pressure directly acting on the back of the tunnel lining will cause the water head in the longitudinal drainage ditches to exceed the road surface elevation. This will result in groundwater gushing outwards in a fountain-like manner through manholes, sedimentation basins, and blind drains under the road surface, causing water accumulation on the road and severely impacting traffic safety within the tunnel. Utility Model Content

[0004] The purpose of this utility model is to address the shortcomings of existing technologies by proposing a tunnel structure with an internal water pressure-resistant drainage system. This structure can prevent lining cracks and prevent groundwater from flowing into the tunnel through the drainage system, construction joints, settlement joints, and deformation joints, thus avoiding road surface water accumulation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A tunnel structure with an internal water pressure-resistant drainage system includes an initial support, an invert arch, a first waterproof layer, a secondary lining, a second waterproof layer, a tertiary lining, and an internal water pressure-resistant drainage system. The second waterproof layer is a fully enclosed self-draining waterproof layer, which consists of geotextile, plastic mesh and waterproof board; the plastic mesh is made of plastic strips with a diameter of 5mm processed into a mesh with a grid size of 1m, the width of the plastic mesh is 9m, and there are 8 longitudinal grooves at equal intervals on the plastic strips, each groove is 2mm deep, and each groove is at an angle of 30 degrees to the horizontal plane. The internal water pressure resistant drainage system includes longitudinal drainage pipes installed within the first and second waterproof layers, a central longitudinal drainage ditch installed within the invert arch filling layer, inspection wells, and transverse drainage pipes.

[0006] Furthermore, the longitudinal drainage pipe is a half-perforated spring pipe with a diameter of 100mm. The elevation of the longitudinal drainage pipe is the same as the inner edge of the arch bottom of the three-layer lining to prevent groundwater from seeping upwards onto the road surface.

[0007] Furthermore, the central longitudinal drainage ditch and inspection well are made of stainless steel pipes; The port of the central longitudinal drainage ditch is enlarged and a rubber seal is added to ensure that there is no leakage when the water pressure inside the pipe increases during longitudinal connection; the interface joints of the transverse drainage pipe are set at equal intervals in the body of the central longitudinal drainage ditch, and a rubber seal is set at the interface joints to ensure that there is no leakage when the water pressure inside the pipe increases during transverse connection. The diameter of the inspection well is the same as that of the central longitudinal drainage ditch, and a connecting joint for the central longitudinal drainage ditch is provided. The distance from the lower edge of the connecting joint to the bottom of the inspection well is not less than 20cm. The top of the inspection well is provided with threads for connecting the well cover to ensure that the well cover does not leak when the water pressure inside the pipe is high. The well cover is provided with bolt holes.

[0008] Furthermore, the initial support consists of 30cm thick C25 shotcrete and I22b steel arch frames.

[0009] Furthermore, the invert arch is constructed using C25 reinforced concrete to enhance the strength and rigidity of the tunnel floor slab, thereby resisting the occurrence of defects such as lining cracking and water leakage caused by uneven settlement of the strata due to factors such as the gradual failure of the grouting curtain layer and vibration loads and redistribution of surrounding rock stress during operation.

[0010] Furthermore, the secondary and tertiary linings are constructed using C30 reinforced concrete with a thickness of no more than 50cm, which reduces defects such as incomplete filling, uneven vibration, and lack of compaction caused by the large thickness of the cast-in-place lining.

[0011] Compared with existing technologies, this technical solution has the following beneficial effects: The tunnel structure of this utility model has strong strength and rigidity, which can avoid lining cracking caused by uneven settlement of the surrounding rock, ensure that the waterproofing ability of the lining itself is not weakened, and resist the increasing water pressure on the lining due to the gradual failure of the water-proofing ability of the surrounding rock in tunnel engineering.

[0012] This invention can reduce the occurrence of defects such as water pressure cracking of the lining and leakage at three joints caused by increased water pressure behind the lining, and can effectively improve the service life of tunnel projects.

[0013] The anti-internal water pressure drainage system adopted in this utility model can ensure that the groundwater does not surface under high pressure, while also retaining the functions of inspection and maintenance. Before maintenance, the groundwater pressure can be detected and appropriate countermeasures can be taken, which greatly reduces the difficulty of maintenance.

[0014] This invention can effectively reduce the probability of water damage in tunnel projects, avoid traffic accidents caused by water damage, reduce the difficulty and cost of tunnel maintenance, improve the service life of tunnel projects and the safety during operation, and has good comprehensive economic and social benefits, making it worthy of promotion. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the tunnel structure described in Example 1.

[0016] Figure 2 This is a schematic diagram of the structure of the second waterproof layer in Example 1.

[0017] Attached reference numerals: 1-First waterproof layer, 2-Secondary lining, 3-Second waterproof layer, 4-Third lining, 5-Invert arch, 6-Inspection well, 7-Central longitudinal drainage ditch, 8-Transverse drainage pipe, 9-Longitudinal drainage pipe, 31-Geotextile, 32-Plastic mesh, 33-Waterproof board. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the embodiments. Specific experimental conditions and methods not specified in the following embodiments are generally conventional methods well known to those skilled in the art.

[0019] Example 1: As Figures 1-2As shown, a tunnel structure with an internal water pressure-resistant drainage system includes initial support, an invert 5, a first waterproof layer 1, a secondary lining 2, a second waterproof layer 3, a third lining 4, and an internal water pressure-resistant drainage system. The second waterproof layer 3 is a fully enclosed self-draining waterproof layer, composed of geotextile 31, plastic mesh 32, and a waterproof board 33. The plastic mesh 32 is made of plastic strips with a diameter of 5mm, processed into a grid with a square size of 1m. The width of the plastic mesh 32 is 9m, and eight longitudinally evenly spaced grooves are engraved on the plastic strips. Each groove is 2mm deep, and the angle between each groove and the horizontal plane is 30 degrees. The internal water pressure-resistant drainage system includes longitudinal drainage pipes 9 installed in the first waterproof layer 1 and the second waterproof layer 3, a central longitudinal drainage ditch 7 installed in the filling layer of the invert 5, and an inspection... The system includes a well 6 and a transverse drainage pipe 8; the longitudinal drainage pipe 9 is a 100mm diameter half-perforated spring pipe, and its elevation is equal to the inner edge of the arch bottom of the tertiary lining 4; the central longitudinal drainage ditch 7 and the inspection well 6 are made of stainless steel pipe; the port of the central longitudinal drainage ditch 7 is enlarged and a rubber seal is added; the transverse drainage pipe 8 interface joints are evenly spaced along the body of the central longitudinal drainage ditch 7, and a rubber seal is provided at the interface joints; the diameter of the inspection well 6 is the same as the diameter of the central longitudinal drainage ditch 7, and a connecting joint for the central longitudinal drainage ditch 7 is provided, with the distance from the lower edge of the connecting joint to the bottom of the inspection well 6 not less than 20cm; the top of the inspection well 6 is provided with threads for connecting the well cover to ensure that the well cover does not leak when the water pressure inside the pipe is high. The manhole cover is provided with bolt holes, which are used to detect the groundwater level and water pressure of the central longitudinal drainage ditch. For example, the bolt holes are connected with M24 bolts and the M24 nuts are equipped with D15 switches. The D15 switches can be connected to an external water pressure gauge. When the water head exceeds the elevation of the manhole cover, it is used to measure the groundwater pressure. When the water head is lower than the elevation of the manhole cover, the M24 bolts can be opened and the groundwater head height can be viewed through the bolt holes.

[0020] The specific construction steps of the tunnel structure with an anti-internal water pressure drainage system described in this embodiment are as follows: (1) Construct a grouting curtain to reinforce the surrounding rock mass; the effective grouting reinforcement thickness of the curtain grouting layer outside the excavation line shall not be less than 5m; (2) Excavate the section above the tunnel invert and construct the initial support for the arch; (3) Excavate the tunnel to enlarge the invert arch and construct the initial support for the enlarged invert arch; the initial support is composed of C25 shotcrete with a thickness of 30cm and I22b steel arch frame; (4) The invert arch is cast with C25 reinforced concrete, and the central longitudinal drainage ditch 7, inspection well 6 and PVC transverse drainage pipe 8 are pre-embedded to resist internal water pressure; and a steel cage along the longitudinal direction of the tunnel is used, and transverse connecting steel bars are set to connect the steel bars arranged along the longitudinal and transverse directions of the tunnel into a whole. (5) Construct the first waterproof layer 1 and the longitudinal drainage pipe 9; the first waterproof layer specifically uses 1.5mm thick PVC waterproof board, Φ100 semi-circular flexible drainage pipe, Φ100Ω spring drainage pipe, Φ160 longitudinal drainage pipe, Φ160 transverse water inlet pipe, 400g / ㎡ geotextile 31, and Φ1000 reinforced concrete longitudinal drainage pipe (wall thickness 10cm). (6) Use C30 reinforced concrete structure with a thickness of no more than 50cm and construct secondary lining 2; (7) Use geotextile 31, plastic mesh 32, PVC waterproof board 33 to construct the second waterproof layer 3 and longitudinal drainage pipe 9, and introduce water flow into the longitudinal drainage pipe 9 at the arch foot; (8) A C30 reinforced concrete structure with a thickness of no more than 50cm is used, and three layers of lining are constructed. (9) Constructing the road surface structure; (10) Clean the sediment in the internal water pressure-resistant drainage system section by section; (11) Other ancillary facilities shall be constructed using the conventional tunnel construction procedures and methods.

[0021] This utility model is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of this utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A tunnel structure including an internal water pressure-resistant drainage system, characterized in that: Includes initial support, invert arch (5), first waterproof layer (1), secondary lining (2), second waterproof layer (3), tertiary lining (4), and internal water pressure-resistant drainage system; The second waterproof layer (3) is a fully enclosed self-draining waterproof layer, which is composed of geotextile (31), plastic mesh (32) and waterproof board (33); the plastic mesh (32) is made of plastic strips with a diameter of 5mm and processed into a mesh with a grid size of 1m. The width of the plastic mesh (32) is 9m. There are 8 grooves longitudinally and evenly spaced on the plastic strips. The depth of each groove is 2mm, and the angle between each groove and the horizontal plane is 30 degrees. The internal water pressure resistant drainage system includes a longitudinal drainage pipe (9) installed in the first waterproof layer (1) and the second waterproof layer (3), a central longitudinal drainage ditch (7) installed in the invert arch filling layer, an inspection well (6), and a transverse drainage pipe (8).

2. The tunnel structure with an internal water pressure-resistant drainage system according to claim 1, characterized in that: The longitudinal drainage pipe (9) is a half-perforated spring pipe with a diameter of 100mm. The elevation of the longitudinal drainage pipe (9) is the same as the inner edge of the arch bottom of the tertiary lining (4).

3. The tunnel structure with an internal water pressure-resistant drainage system according to claim 1, characterized in that: The central longitudinal drainage ditch (7) and the inspection well (6) are made of stainless steel pipes; the port of the central longitudinal drainage ditch (7) is enlarged and a rubber seal is added; the ditch body of the central longitudinal drainage ditch (7) is provided with interface joints of transverse drainage pipes (8) at equal intervals, and a rubber seal is provided at the interface joints; the diameter of the inspection well (6) is the same as the diameter of the central longitudinal drainage ditch (7), and a connecting joint of the central longitudinal drainage ditch (7) is provided, the distance from the lower edge of the connecting joint to the bottom of the inspection well (6) is not less than 20cm; the top of the inspection well (6) is provided with threads for connecting the well cover; the well cover is provided with bolt holes.

4. The tunnel structure with an internal water pressure-resistant drainage system according to claim 1, characterized in that: The initial support consists of 30cm thick C25 shotcrete and I22b steel arch frames.

5. The tunnel structure with an internal water pressure-resistant drainage system according to claim 1, characterized in that: The inverted arch (5) is constructed using C25 reinforced concrete.

6. The tunnel structure with an internal water pressure-resistant drainage system according to claim 1, characterized in that: The secondary lining (2) and the tertiary lining (4) are made of C30 reinforced concrete with a thickness of no more than 50cm.

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