Tunnel portal waterproof and drainage system at joint of bridge and tunnel

Abstract

The utility model discloses a waterproof and drainage system for a tunnel portal at the joint of a bridge and a tunnel, which comprises a central drainage ditch 3-1 and a drainage side ditch 3-2, and is characterized by comprising a first transverse drainage pipe 3-5 which is close to the tunnel portal at the joint of the bridge and the tunnel and is connected with the central drainage ditch 3-1; the first longitudinal drainage pipe 3-6 is connected with the first transverse drainage pipe 3-5 and is used for draining the lined underground water of the central drainage ditch 3-1 to a first water outlet penetrating through a bridge pheasant wall 2-1; the second transverse drainage pipe 3-3 is close to a tunnel portal at the junction of the bridge and the tunnel and is connected with the drainage side ditch 3-2; the second longitudinal drainage pipe 3-4 is connected with the second transverse drainage pipe 3-3 and is used for discharging sewage of the drainage side ditch 3-2 to a second water outlet penetrating through the bridge pheasant wall 2-1, so that accumulated water in the tunnel is directionally led out of a tunnel opening by utilizing a drainage system of the tunnel, the flushing to a bridge abutment during drainage is avoided, and the service life of the tunnel is prolonged. Meanwhile, the function of separated discharge of underground water and sewage is achieved.

Description

Technical Field

[0001] The utility model belongs to the field of highway engineering, and specifically relates to a tunnel opening drainage system at the junction of a bridge and a tunnel. Background Art

[0002] In recent years, with the rapid development of my country's infrastructure construction, especially highways, it has gradually shifted from plains to mountainous areas. Unlike plain highways, mountainous areas have complex terrain conditions, steep slopes, and the phenomenon of bridge-tunnel connection is common. The use of bridge-tunnel connection can effectively maintain the stability of the tunnel entrance, avoid landslides, improve the stability of the abutment, and protect the natural environment around the highway. It is a frequently used technical means in mountain highway construction.

[0003] There are three common types of bridge-tunnel connections, namely short roadbed connection, bridge-into-tunnel type, and tunnel portal abutment treatment type. The main problems with drainage engineering for the three types of bridge-tunnel connections are as follows: (1) Short roadbed connection is the most common type of bridge-tunnel connection at present, but this practice violates the principle of "early entry and late exit" of the tunnel, and the traditional tunnel portal ditch only has the tunnel side ditch or the central ditch. This traditional tunnel portal drainage system has poor drainage effect. When the water volume is large, it is easy to cause groundwater at the tunnel portal, which is difficult to repair and easy to cause erosion of the abutments and beams. In addition, the tunnel sewage is directly discharged outside the tunnel, which is not conducive to environmental protection; (2) The type of bridge-into-tunnel connection, its drainage system is not suitable for tunnels with large water volume. The quality control of drainage projects is difficult. The main reasons are: limited by the current construction level of tunnel projects, the level of bridge installation, the trend of the mountain, and the current status of engineering design and construction, drainage projects are prone to internal reverse seepage, drainage backflow, and water accumulation in the tunnel in the later application, which is not conducive to the safe and stable application of the project in the later stage; (3) Tunnel portal abutment type, which is characterized by the relatively independent design and construction of the bridge and tunnel projects. The drainage system needs to meet the construction design characteristics of the two projects at the same time in the design, but the overall project cost is low, and the construction period of the project is short, with few safety hazards during construction. Therefore, this type of construction plan has a wide range of applications and good application effects.

[0004] In mountainous areas where tunnels pass, groundwater is generally abundant, and together with various operational wastewater, it becomes the main factor endangering the durability of tunnel structures. Water leakage is the most common problem in highway tunnels and is a sign of failure of the tunnel's drainage system.

[0005] Therefore, there is an urgent need to provide a tunnel opening drainage system at the junction of a bridge and a tunnel, which can solve the water leakage problem in the prior art, extend the service life of the tunnel, and ensure driving safety. Utility Model Content

[0006] The utility model aims to provide a tunnel opening drainage system at the junction of a bridge and a tunnel, which can solve the above technical problems.

[0007] According to one aspect of the utility model, a tunnel opening drainage system at the junction of a bridge and a tunnel is provided, comprising a central drainage ditch 3-1 and a drainage side ditch 3-2, and characterized in that it comprises: a first transverse drainage pipe 3-5, close to the tunnel opening at the junction of the bridge and the tunnel, connected to the central drainage ditch 3-1; a first longitudinal drainage pipe 3-6, connected to the first transverse drainage pipe 3-5, for discharging the lining groundwater of the central drainage ditch 3-1 to a first outlet that passes through the bridge wall 2-1; a second transverse drainage pipe 3-3, close to the tunnel opening at the junction of the bridge and the tunnel, connected to the drainage side ditch 3-2; a second longitudinal drainage pipe 3-4, connected to the second transverse drainage pipe 3-3, for discharging the sewage of the drainage side ditch 3-2 to a second outlet that passes through the bridge wall 2-1.

[0008] Preferably, the tunnel portal drainage system at the junction of the bridge and the tunnel also includes: a plurality of third transverse drainage pipes 3-8, respectively connected to the central drainage ditch 3-1; a third longitudinal drainage pipe 3-7, which is arranged through the bottom of the initial support of the side walls on both sides of the tunnel and is connected to the plurality of third transverse drainage pipes 3-8, and its longitudinal slope is the same as the longitudinal slope of the road design line of the tunnel; a plurality of annular soft permeable blind pipes 3-9, which are arranged at intervals between the secondary lining structure 1-1 of the tunnel and the initial support, and are respectively connected to the third longitudinal drainage pipe 3-7, for draining the groundwater behind the lining to the central drainage ditch 3-1.

[0009] Preferably, the plurality of third transverse drainage pipes 3-8 and the third longitudinal drainage pipes 3-7 are all HDPE pipes with a diameter of 11 cm, and the diameters of the plurality of annular soft permeable blind pipes 3-9 are all 5 cm.

[0010] Preferably, the plurality of third transverse drainage pipes 3-8 and the plurality of annular soft permeable blind pipes 3-9 are arranged at intervals of 5m along the longitudinal direction of the tunnel; the plurality of third transverse drainage pipes 3-8, the plurality of annular soft permeable blind pipes 3-9 and the third longitudinal drainage pipe 3-7 are all wrapped with non-woven fabric.

[0011] Preferably, the secondary lining structure 1-1 is an integral cast-in-place concrete structure using C40 impermeable concrete, and its impermeability grade is not lower than P8.

[0012] Preferably, a waterproof layer is also provided between the secondary lining structure and the initial support, including: a 1.5 cm thick root-penetration-proof EAC waterproof board 1-2 located in the inner layer; a 400 g / m2 non-woven fabric 1-3 located in the middle layer; and a 7 cm thick C20 fine stone concrete 1-4 located in the outer layer.

[0013] Preferably, the tunnel portal drainage system at the junction of the bridge and the tunnel also includes: mortar-laid flagstones 1-5, which are backfill materials within 7m above the bottom of the side walls on both sides of the tunnel, using MU40 flagstones and M7.5 mortar respectively; multiple layers of crushed stone 1-6 and a 50cm thick clay waterproofing layer 1-7, which are backfilled in sequence above the mortar-laid flagstones 1-5 to prevent surface water from seeping in; cultivated soil 1-8, covering the clay waterproofing layer 1-7 with a covering thickness of 100cm, for restoring vegetation.

[0014] Preferably, the first transverse drainage pipe 3-5 and the first longitudinal drainage pipe 3-6 are both made of HDPE pipe with a diameter of 60 cm; the second transverse drainage pipe 3-3 and the second longitudinal drainage pipe 3-4 are both made of steel pipe with a diameter of 300 mm and a wall thickness of 4 mm.

[0015] Preferably, the transverse slope of the second transverse drainage pipe 3-3 is higher than 2%, so as to allow the sewage in the drainage ditch to quickly flow into the second longitudinal drainage pipe 3-4.

[0016] Preferably, the first transverse drain pipe 3-5 and the first longitudinal drain pipe 3-6, as well as the second transverse drain pipe 3-3 and the second longitudinal drain pipe 3-4, are connected by a tee.

[0017] The utility model provides a tunnel opening waterproofing and drainage system at the junction of a bridge and a tunnel, comprising a central drainage ditch 3-1 and a drainage side ditch 3-2, and is characterized in that it comprises: a first transverse drainage pipe 3-5, which is close to the tunnel opening at the junction of the bridge and the tunnel and is connected to the central drainage ditch 3-1; a first longitudinal drainage pipe 3-6, which is connected to the first transverse drainage pipe 3-5 and is used to discharge the lining-back groundwater of the central drainage ditch 3-1 to a first outlet that passes through the bridge wall 2-1; a second transverse drainage pipe 3-3, which is close to the tunnel opening at the junction of the bridge and the tunnel and is connected to the drainage side ditch 3-2; a second longitudinal drainage pipe 3-4, which is connected to the second transverse drainage pipe 3-3 and is used to discharge the sewage of the drainage side ditch 3-2 to a second outlet that passes through the bridge wall 2-1, so that the drainage system of the tunnel itself is used to direct the accumulated water in the tunnel out of the opening, so as to avoid scouring of the bridge abutment during drainage, and at the same time meet the function of separating and discharging groundwater and sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0019] Figure 1 It is a schematic plan view of a tunnel opening drainage system at the junction of a bridge and a tunnel according to an embodiment of the utility model;

[0020] Figure 2 It is a schematic elevation view of a tunnel opening drainage system at the junction of a bridge and a tunnel according to an embodiment of the utility model;

[0021] Among them, 0-1, the location of the bridge-tunnel junction; 0-2, the longitudinal center line of the tunnel; 1-1, the secondary lining structure; 1-2, the EAC waterproof board to prevent root penetration; 1-3, non-woven fabric; 1-4, fine stone concrete; 1-5, mortared flagstones; 1-6, crushed stone soil; 1-7, clay waterproof layer; 1-8, cultivated soil; 1-9, the same grade concrete of the second lining; 1-10, crushed stone filter layer; 2-1, the primary wall of the bridge; 2-2, the abutment; 3-1, the central drainage ditch; 3-2, the drainage ditch; 3-3, the second transverse drainage pipe; 3-4, the second longitudinal drainage pipe; 3-5, the first transverse drainage pipe; 3-6, the first longitudinal drainage pipe; 3-7, the third longitudinal drainage pipe; 3-8, the third transverse drainage pipe; 3-9, the annular soft permeable blind pipe. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] Reference will now be made in detail to various embodiments of the present invention, examples of which are shown in the accompanying drawings and described below. For ease of interpretation and precise definition in the appended claims, the terms "upper", "lower", "inner" and "outer" are used to describe features of the exemplary embodiments shown in the drawings with reference to their positions.

[0024] Figure 1 and Figure 2 The plan view and elevation view of a tunnel opening drainage system at the junction of a bridge and a tunnel according to an embodiment of the utility model are shown respectively. Figure 1 , Figure 2 As shown, the tunnel opening drainage system at the junction of the bridge and the tunnel includes a central drainage ditch 3-1 and a drainage side ditch 3-2, and is characterized in that it includes: a first transverse drainage pipe 3-5, which is close to the tunnel opening at the junction of the bridge and the tunnel and is connected to the central drainage ditch 3-1; a first longitudinal drainage pipe 3-6, which is connected to the first transverse drainage pipe 3-5 and is used to discharge the groundwater after lining of the central drainage ditch 3-1 to the first outlet that passes through the bridge wall 2-1; a second transverse drainage pipe 3-3, which is close to the tunnel opening at the junction of the bridge and the tunnel and is connected to the drainage side ditch 3-2; a second longitudinal drainage pipe 3-4, which is connected to the second transverse drainage pipe 3-3 and is used to discharge the sewage of the drainage side ditch 3-2 to the second outlet that passes through the bridge wall 2-1.

[0025] According to the embodiment of the utility model, the first transverse drainage pipe 3-5 and the first longitudinal drainage pipe 3-6 both adopt HDPE pipe with a diameter of 60 cm; the second transverse drainage pipe 3-3 and the second longitudinal drainage pipe 3-4 both adopt steel pipe with a diameter of 300 mm and a wall thickness of 4 mm.

[0026] According to the embodiment of the utility model, the transverse slope of the second transverse drainage pipe 3-3 is higher than 2%, so as to allow the sewage in the drainage ditch to quickly flow into the second longitudinal drainage pipe 3-4.

[0027] According to the embodiment of the utility model, the first transverse drainage pipe 3-5 and the first longitudinal drainage pipe 3-6, as well as the second transverse drainage pipe 3-3 and the second longitudinal drainage pipe 3-4, are both connected by three-way connection.

[0028] In the prior art, tunnel drainage is usually used to directly flush the abutment, resulting in its structure being affected. The utility model of the drainage system at the junction of the bridge and the tunnel, at the tunnel-bridge junction position 0-1, the sewage of the drainage side ditches 3-2 on both sides is led to the back of the bridge wall 2-2 in a horizontal direction with a slope higher than 2% through the 300*4mm second transverse drainage pipe 3-3, and then the sewage is led to the second water outlet of the bridge wall 2-2 by turning 90 degrees through the 300*4mm second longitudinal drainage pipe 3-4 connected by a tee; on the other hand, the central drainage ditch (3-1) is buried under the road surface along the longitudinal center line 0-2 of the tunnel, and the groundwater therein needs to be led to the back of the beam wall 2-2 by the 60cmHDPE first transverse drainage pipe 3-5, and then led to the first water outlet of the bridge wall 2-2 by the 60cmHDPE first longitudinal drainage pipe 3-6 connected by a tee to achieve slow drainage. In addition, in order to ensure that the drainage pipes of the drainage system at the junction of the bridge and the tunnel can drain water smoothly, the transverse slope of the first transverse drainage pipe 3-5, and the longitudinal slopes of the first longitudinal drainage pipe 3-6 and the second longitudinal drainage pipe shall not be less than 0.3%. This method drains the groundwater collected in the tunnel to the outside of the tunnel, avoiding the groundwater in the tunnel from directly scouring the abutment 2-1, and realizing the clear and turbid separation function of the drainage system at the junction of the bridge and the tunnel.

[0029] According to the embodiment of the utility model, the tunnel portal drainage system at the junction of the bridge and the tunnel also includes: a plurality of third transverse drainage pipes 3-8, respectively connected to the central drainage ditch 3-1; a third longitudinal drainage pipe 3-7, which is arranged through the bottom of the initial support of the side walls on both sides of the tunnel and is connected to the plurality of third transverse drainage pipes 3-8, and its longitudinal slope is the same as the longitudinal slope of the road design line of the tunnel; a plurality of annular soft permeable blind pipes 3-9, which are arranged at intervals between the secondary lining structure 1-1 of the tunnel and the initial support, and are respectively connected to the third longitudinal drainage pipe 3-7, for draining the groundwater behind the lining to the central drainage ditch 3-1.

[0030] According to the embodiment of the utility model, the plurality of third transverse drainage pipes 3-8 and the third longitudinal drainage pipe 3-7 are all HDPE pipes with a diameter of 11 cm, and the diameter of the plurality of annular soft permeable blind pipes 3-9 is 5 cm.

[0031] According to an embodiment of the utility model, the plurality of third transverse drainage pipes 3-8 and the plurality of annular soft permeable blind pipes 3-9 are arranged at intervals of 5m along the longitudinal direction of the tunnel; the plurality of third transverse drainage pipes 3-8, the plurality of annular soft permeable blind pipes 3-9 and the third longitudinal drainage pipe 3-7 are all wrapped with non-woven fabric.

[0032] According to the embodiment of the utility model, the drainage system at the junction of the bridge and the tunnel cooperates with the tunnel self-drainage system to complete the drainage work. The specific composition of the tunnel self-drainage system is as follows:

[0033] 1) The circular central drainage ditch 3-1 below the tunnel pavement serves as the main longitudinal drainage ditch in the tunnel;

[0034] 2) Drainage ditches 3-2 on the left and right sides of the tunnel pavement to drain road water and cleaning water in the tunnel;

[0035] 3) A 11cm HDPE third longitudinal drainage pipe 3-7 is set at the bottom of the initial support of the side walls on both sides of the tunnel to drain the groundwater behind the lining, and the water in the third longitudinal drainage pipe 3-7 on the back of the wall is drained to the central drainage ditch 3-1 through the set 11cm HDPE third transverse drainage pipe 3-8. The third longitudinal drainage pipe 3-7 and the third transverse drainage pipe 3-8 are connected by a tee;

[0036] 4) The annular soft permeable blind pipe 3-9 between the initial support and the secondary lining structure 1-1, the third longitudinal drainage pipe 3-7 is longitudinally connected, and its longitudinal slope is consistent with the road design line. The third transverse drainage pipe 3-8 and the annular soft permeable blind pipe 3-9 are set at a tunnel spacing of 5m, which can be adjusted according to the actual water discharge situation on site;

[0037] 5) The third longitudinal drainage pipe 3-7, the third transverse drainage pipe 3-8, and the annular soft permeable blind pipe 3-9 are all wrapped with non-woven fabric.

[0038] According to the embodiment of the utility model, the secondary lining structure 1-1 is an integral cast-in-place concrete structure using C40 impermeable concrete, and its impermeability grade is not lower than P8.

[0039] According to an embodiment of the utility model, a waterproof layer is also arranged between the secondary lining structure and the initial support, including: a 1.5 cm thick anti-root penetration EAC waterproof board 1-2 located in the inner layer; a 400 g / m2 non-woven fabric 1-3 located in the middle layer; and a 7 cm thick C20 fine stone concrete 1-4 located in the outer layer.

[0040] According to the embodiment of the utility model, the tunnel portal drainage system at the junction of the bridge and the tunnel also includes: mortar-laid stone 1-5, which is the backfill material within 7m above the bottom of the side walls on both sides of the tunnel, and MU40 stone and M7.5 mortar are used respectively; multiple layers of crushed stone 1-6 and 50cm thick clay waterproof layer 1-7 are backfilled in sequence above the mortar-laid stone 1-5 to prevent surface water from seeping in; cultivated soil 1-8, covering above the clay waterproof layer 1-7, with a covering thickness of 100cm, for restoring vegetation.

[0041] In order to prevent the amount of water accumulated in the tunnel from exceeding the drainage capacity of the drainage system, the tunnel needs to be waterproofed accordingly to prevent surface water from penetrating along the tunnel lining structure. The tunnel self-waterproofing system specifically includes:

[0042] 1) A secondary lining structure 1-1 of integral cast-in-place waterproof reinforced concrete is adopted. The secondary lining structure 1-1 adopts an integral cast-in-place concrete structure and adopts C40 impermeable concrete, and its impermeability grade is not lower than P8;

[0043] 2) Waterproof layer of the arch of the open hole: from outside to inside, it is composed of 7cmC20 fine stone concrete 1-4+400g / m2 non-woven fabric 1-3+1.5mm thick anti-root puncture EVA waterproof board 1-2;

[0044] 3) MU40 and M7.5 mortar-laid stone 1-5 within 7m above the bottom of the side walls on both sides can be used as backfill to make the structure evenly stressed. Gravel soil 1-6 is rammed layer by layer on the mortar-laid stone 1-5, and then a 50cm thick clay waterproof layer is rammed to prevent surface water from seeping in. The surface is covered with 100cm of cultivated soil to restore vegetation, so as to achieve the goal of harmonious coexistence between engineering construction and the ecological environment.

[0045] In addition, a crushed stone filter layer 1-10 is provided outside the arch foot of the tunnel, and a secondary lining of the same grade concrete 1-9 is used below it.

[0046] The embodiment of the utility model comprises three major parts: a drainage system at the junction of a bridge and a tunnel, a tunnel self-drainage system and a tunnel self-waterproofing system, forming a complete tunnel opening drainage system at the junction of a bridge and a tunnel.

[0047] The utility model has the following effects:

[0048] (1) The structural characteristics of the bridge abutment and the tunnel opening are cleverly utilized, and the functionality of the original bridge-tunnel structure and the integrity of the drainage system are maintained. On the basis of achieving the drainage design requirements such as improving the drainage capacity of the tunnel opening, preventing tunnel leakage, and preventing bridge abutment scouring, the safety of tunnel construction at the junction of the district highway bridge and tunnel, as well as the smoothness and maintainability of drainage during the operation period, are effectively improved;

[0049] (2) The clear and turbid water separation function of the tunnel entrance drainage system has improved the green level of mountain highway construction, fully implemented the green, low-carbon and environmentally friendly development concept, and has important practical significance and demonstration effect on promoting the sustainable development of mountain highway construction.

[0050] The above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other changes or modifications in different forms may be made based on the following description, and these changes, modifications, substitutions and deformations derived from the principles and spirit of the present invention still fall within the scope of protection of the present invention.

Claims

1. A tunnel portal drainage system at the junction of a bridge and a tunnel, comprising a central drainage ditch (3-1) and a drainage side ditch (3-2), characterized in that: include: A first transverse drainage pipe (3-5), located near the tunnel opening where the bridge and tunnel meet, connected to the central drainage ditch (3-1); A first longitudinal drainage pipe (3-6) connected to the first transverse drainage pipe (3-5) and used to drain the lining groundwater of the central drainage ditch (3-1) to a first outlet that penetrates the bridge ridge wall (2-1); A second transverse drainage pipe (3-3), located near the tunnel opening where the bridge and tunnel meet, connected to the drainage ditch (3-2); The second longitudinal drainage pipe (3-4) is connected to the second transverse drainage pipe (3-3) and is used to discharge sewage from the drainage ditch (3-2) to a second water outlet that passes through the bridge ridge (2-1).

2. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 1 is characterized in that: Also includes: A plurality of third transverse drainage pipes (3-8), respectively connected to the central drainage ditch (3-1); A third longitudinal drainage pipe (3-7) is arranged through the bottom of the initial support of the side walls on both sides of the tunnel and is connected to the plurality of third transverse drainage pipes (3-8), and its longitudinal slope is the same as the longitudinal slope of the road design line of the tunnel; A plurality of annular soft permeable blind pipes (3-9) are arranged at intervals between the secondary lining structure (1-1) of the tunnel and the initial support, and are respectively connected to the third longitudinal drainage pipe (3-7) to drain the post-lining groundwater to the central drainage ditch (3-1).

3. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 2 is characterized in that: The plurality of third transverse drainage pipes (3-8) and the third longitudinal drainage pipes (3-7) are all HDPE pipes with a diameter of 11 cm, and the diameters of the plurality of annular soft permeable blind pipes (3-9) are all 5 cm.

4. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 3 is characterized by: The plurality of third transverse drainage pipes (3-8) and the plurality of annular soft permeable blind pipes (3-9) are arranged at intervals of 5 m along the longitudinal direction of the tunnel; The plurality of third transverse drainage pipes (3-8), the plurality of annular soft water-permeable blind pipes (3-9) and the third longitudinal drainage pipe (3-7) are all wrapped with non-woven fabric.

5. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 2 is characterized in that: The secondary lining structure (1-1) is an integral cast-in-place concrete structure using C40 impermeable concrete, and its impermeability grade is not lower than P8.

6. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 5, characterized in that: A waterproof layer is also provided between the secondary lining structure and the initial support, including: 1.5 cm thick EAC waterproofing sheet (1-2) to prevent root penetration located in the inner layer; 400g / m in the middle layer 2 Nonwoven fabrics (1-3); and The outer layer is 7 cm thick C20 fine aggregate concrete (1-4).

7. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 1, characterized in that: Also includes: Mortared stone slabs (1-5) are backfill materials within 7m above the bottom of the side walls on both sides of the tunnel, using MU40 stone slabs and M7.5 mortar respectively; Multiple layers of crushed stone soil (1-6) and a 50 cm thick clay waterproof layer (1-7) are backfilled in sequence above the mortar-laid rubble (1-5) to prevent surface water from seeping in; The cultivated soil (1-8) is covered on the clay waterproof layer (1-7) with a covering thickness of 100 cm and is used for restoring vegetation.

8. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 1, characterized in that: The first transverse drainage pipe (3-5) and the first longitudinal drainage pipe (3-6) are both made of HDPE pipe with a diameter of 60 cm; The second transverse drainage pipe (3-3) and the second longitudinal drainage pipe (3-4) are both made of steel pipes with a diameter of 300 mm and a wall thickness of 4 mm.

9. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 1, characterized in that: The transverse slope of the second transverse drainage pipe (3-3) is higher than 2%, so as to allow the sewage in the drainage ditch to quickly flow into the second longitudinal drainage pipe (3-4).

10. The tunnel opening drainage system at the junction of a bridge and a tunnel according to claim 1, characterized in that: The first transverse drainage pipe (3-5) and the first longitudinal drainage pipe (3-6), as well as the second transverse drainage pipe (3-3) and the second longitudinal drainage pipe (3-4), are both connected by a tee.

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