Lining drainage structure of hydraulic pressure tunnel and construction method thereof

Abstract

The invention discloses a lining drainage structure of a hydraulic pressure tunnel and a construction method of the lining drainage structure. The drainage structure comprises double-layer permeable template cloth which is arranged between a primary support layer and a secondary lining layer of a tunnel wall; wherein the outer-layer water-permeable template cloth water-permeable layer is fixed and attached to the surface of the primary support layer; the inner-layer permeable template cloth permeable layer is fixed and attached to the surface of the secondary lining layer, and the inner-layer permeable template cloth filter layer and the outer-layer permeable template cloth filter layer are attached to each other; air holes which are permeable to water and air and are not permeable to slurry are formed in the outer-layer permeable template cloth permeable layer and the inner-layer permeable template cloth permeable layer in a penetrating manner; the outer-layer water-permeable template cloth filter layer and the inner-layer water-permeable template cloth filter layer are respectively of a fluffy structure with water retention and air permeability; a drainage pipe leading to the outer side of the tunnel is embedded in the wall of the tunnel, and an orifice of the drainage pipe is formed in the drainage hole. High-pressure underground water can be collected to other drainage holes through the drainage cushion layer and then is finally drained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tunnel structure design and construction technology, in particular to a lining drainage structure of a hydraulic pressure tunnel and a construction method thereof. BACKGROUND

[0002] With the development of economy and society, water resource problems are increasingly prominent, and the demand for inter-basin water transfer in many regions is increasingly strong. Long-distance water transfer projects have two ways, namely, open channel and tunnel water conveyance. Among them, tunnel water conveyance has become the main means for realizing long-distance water transfer projects due to its flexible arrangement and less impact on the ground environment. With the development of society and economy and the needs of water conservancy planning, it is increasingly inevitable to build super-long and deep-buried pressure tunnels in mountainous areas.

[0003] Deep-buried pressure tunnels not only have a large operating internal water pressure, but also face high external water problems. Higher external water pressure will lead to the destruction of the secondary lining structure of the tunnel, which is an important aspect of restricting the safety of the project. Through tunnel seepage prevention and drainage, the design concept of seepage prevention and drainage has experienced a change from "mainly drainage" to "mainly plugging" and then to "mainly plugging with limited drainage". "Plugging" means controlling the seepage flow of the tunnel, increasing the ability of the rock mass to resist external water pressure through tunnel seepage prevention grouting, and "drainage" means effectively reducing the water pressure around the secondary lining structure of the tunnel through measures such as setting drainage holes. The "mainly plugging with limited drainage" waterproof design effectively reduces the water pressure around the secondary lining structure of the tunnel by alternately and intervally arranging drainage holes in the axial direction of the tunnel to ensure the safety of the secondary lining structure of the tunnel.

[0004] However, as an independent drainage "point" unit, there is still water pressure in the complete rock mass between two drainage points. If the drainage hole does not penetrate the water-conducting channel, the drainage hole is ineffective. When the drainage hole is blocked or fails, local water pressure accumulates, causing the lining to crack or even fall off, which poses a safety hazard to the tunnel structure. SUMMARY

[0005] In view of the shortcomings of the prior art, the present application provides a lining drainage structure of a hydraulic pressure tunnel and a construction method thereof, which breaks through the traditional drainage method and uses a double-layer permeable formwork cloth as a planar drainage network layer to solve the problem of high external water caused by easy blockage or failure of the drainage hole.

[0006] To achieve the above-mentioned purpose, the present application designs a lining drainage structure of a hydraulic pressure tunnel, which is characterized in that: a double-layer permeable formwork cloth is arranged between the primary support layer and the secondary lining layer of the tunnel wall, the double-layer permeable formwork cloth includes an outer layer permeable formwork cloth and an inner layer permeable formwork cloth, and the double-layer permeable formwork cloth is in a sealed state at the positions around. The outer layer water-permeable formwork cloth comprises an outer layer water-permeable formwork cloth water-permeable layer and an outer layer water-permeable formwork cloth filter layer, and the outer layer water-permeable formwork cloth water-permeable layer is fixed and attached to the surface of the primary support layer; The inner layer water-permeable formwork cloth comprises an inner layer water-permeable formwork cloth water-permeable layer and an inner layer water-permeable formwork cloth filter layer, and the inner layer water-permeable formwork cloth water-permeable layer is fixed and attached to the surface of the secondary lining layer, and the inner layer water-permeable formwork cloth filter layer is attached to the outer layer water-permeable formwork cloth filter layer; The outer layer water-permeable formwork cloth water-permeable layer and the inner layer water-permeable formwork cloth water-permeable layer are both provided with air-permeable holes for water permeation, air permeation and non-grout permeation; the outer layer water-permeable formwork cloth filter layer and the inner layer water-permeable formwork cloth filter layer are both provided with a porous structure with water retention and air permeation performance, and a water drainage and air permeation cavity is formed between the inner layer water-permeable formwork cloth filter layer and the outer layer water-permeable formwork cloth filter layer; The double-layer water-permeable formwork cloth is provided with grouting holes and drainage holes penetrating in and out, and the periphery of the grouting hole and the drainage hole is in a sealed state; The drainage pipe is buried in the tunnel wall and is connected to the outside of the tunnel, and the hole of the drainage pipe is arranged in the drainage hole.

[0007] Further, the outer layer water-permeable formwork cloth water-permeable layer and the inner layer water-permeable formwork cloth water-permeable layer are both hydrophilic materials, and the average pore diameter of the air-permeable holes on the outer layer water-permeable formwork cloth water-permeable layer and the inner layer water-permeable formwork cloth water-permeable layer is 20-35 μm.

[0008] Further, the outer layer water-permeable formwork cloth filter layer and the inner layer water-permeable formwork cloth filter layer have a thickness of 1-2.5 mm, have water retention and air permeation performance, have a water retention capacity greater than 0.25 L / m2, and have a water drainage capacity greater than 0.4 L / m2.

[0009] Further, the outer layer water-permeable formwork cloth and the inner layer water-permeable formwork cloth both use modified high-molecular polypropylene fibers as the main raw material.

[0010] The application also designs a construction method of a lining drainage structure of a hydraulic pressure tunnel, which is suitable for the above-mentioned lining drainage structure of the hydraulic pressure tunnel, and has the following steps: S1) preparing the double-layer water-permeable formwork cloth and checking the performance index, and sticking and fixing the patch on the outside of the outer layer water-permeable formwork cloth; S2) removing the protrusions on the surface of the primary support layer, and leveling the concave pits on the surface of the primary support layer with the mortar; S3) drilling holes in the tunnel wall and installing the drainage pipe; S4) passing the drainage hole of the double-layer water-permeable formwork cloth through the drainage pipe, and fixing the patch together with the double-layer water-permeable formwork cloth on the surface of the primary support layer by using hot melt glue nails; S5) performing secondary lining layer construction and pouring.

[0011] Further, in S1), the four sides of the double-layer water-permeable formwork cloth are sealed by hot melting.

[0012] Further, in S3), the geotextile is wrapped around the drain hole to form a filter layer.

[0013] Further, in S4), the hot-melt glue nails are compatible with the double-layer water-permeable formwork cloth and the concrete surface.

[0014] Further, in S4), a geotextile is arranged between the primary support layer and the double-layer water-permeable formwork cloth before laying the double-layer water-permeable formwork cloth.

[0015] The advantages of the present application are as follows: 1. The present application breaks through the traditional drainage pressure reduction method. By arranging a double-layer water-permeable formwork cloth between the primary support layer and the secondary lining layer of the tunnel, a drainage cushion layer is formed, and a network space is formed between the primary support layer and the secondary lining layer of the tunnel. The high-pressure underground water is collected and discharged in an organized manner. The high external water problem caused by the blockage or failure of a certain drainage hole can be solved. The engineering risk caused by the failure of the traditional point-shaped drainage hole is reduced. 2. The double-layer water-permeable formwork cloth in the present application has the characteristics of water permeability and air permeability. During the concrete construction process, the drainage and air permeability can reduce the aggregation of concrete bubbles, improve the surface density of the concrete, and thus improve the impermeability of the lining concrete, and further improve the durability of the concrete. 3. By arranging the above-mentioned double-layer water-permeable formwork cloth drainage cushion layer between the primary support layer and the secondary lining layer, the restraining effect of the surrounding rock on the concrete pouring process can be reduced, and the temperature cracks caused by the inadequate temperature control measures of the lining concrete can be reduced, thereby better ensuring the pouring quality of the lining concrete.

[0016] 4. The construction process of the present application is simple, time-saving, and the construction materials are easy to obtain, with low cost and easy popularization. The lining drainage structure of the hydraulic pressure tunnel and the construction method thereof can make the high-pressure underground water collected through the drainage cushion layer to other drainage holes and finally discharged, solving the high external water problem caused by the blockage or failure of a certain drainage hole. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a front view of the lining drainage structure of the hydraulic pressure tunnel of the present application; Figure 2 is Figure 1 a local enlarged view in Figure 3This is a construction method flowchart for the lining drainage structure of the hydraulic pressurized tunnel of the present invention. Figure 4 This is a front view of a double-layer permeable template fabric that has undergone heat fusion treatment; Figure 5 Side view of the installation of the permeable template fabric after heat fusion treatment; In the diagram: 1. Excavation boundary; 2. Initial support layer; 3. Drainage pipe; 4. Outer permeable formwork fabric; 5. Inner permeable formwork fabric; 6. Secondary lining layer; 8. Fixing patch; 9. Hot melt adhesive nail; 10. Grouting hole; 11. Drainage hole. The outer permeable template fabric 4 includes: an outer permeable template fabric permeable layer 4-1 and an outer permeable template fabric filter layer 4-2; The inner permeable template fabric 5 includes: an inner permeable template fabric permeable layer 5-1 and an inner permeable template fabric filter layer 5-2. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", 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 the invention.

[0020] Example 1 like Figures 1-2 As shown, the present invention discloses a lining drainage structure for a pressurized hydraulic tunnel, comprising a double-layer permeable template fabric disposed between the initial support layer 2 and the secondary lining layer 6 of the tunnel wall, wherein the double-layer permeable template fabric comprises an outer permeable template fabric 4 and an inner permeable template fabric 5; and the double-layer permeable template fabric is sealed at all four sides.

[0021] The outer permeable template fabric 4 includes an outer permeable template fabric permeable layer (smooth surface) 4-1 and an outer permeable template fabric filter layer (textured surface) 4-2, and the outer permeable template fabric permeable layer (smooth surface) 4-1 is fixed and attached to the surface of the initial support layer 2.

[0022] The inner permeable template fabric 5 includes an inner permeable template fabric permeable layer (smooth surface) 5-1 and an inner permeable template fabric filter layer (rough surface) 5-2. The inner permeable template fabric permeable layer (smooth surface) 5-1 is fixed and attached to the surface of the secondary lining layer 6, and the inner permeable template fabric filter layer (rough surface) 5-2 and the outer permeable template fabric filter layer (rough surface) 4-2 are heat-fused together.

[0023] Both the outer permeable template fabric permeable layer (smooth surface) 4-1 and the inner permeable template fabric permeable layer (smooth surface) 5-1 have permeable pores for water and air permeability, but without slurry permeability; both the outer permeable template fabric filter layer (textured surface) 4-2 and the inner permeable template fabric filter layer (textured surface) 5-2 are loose structures with water retention and air permeability, and a drainage and air permeable cavity is formed between the inner permeable template fabric filter layer (textured surface) 5-2 and the outer permeable template fabric filter layer (textured surface) 4-2.

[0024] The double-layer permeable template fabric has grouting holes 10 and drainage holes 11 that penetrate from the inside out, and the openings of the grouting holes 10 and drainage holes 11 are sealed.

[0025] like Figure 1 As shown, the initial support layer 2 is set on the surface of the excavation boundary 1. Double-layer permeable formwork is installed at the top of the tunnel using a specialized installation trolley. The lining drainage structure is arranged from the outside to the inside in the following order: excavation boundary 1, initial support layer 2, outer permeable formwork permeable layer (smooth surface) 4-1, outer permeable formwork filter layer (rough surface) 4-2, inner permeable formwork filter layer (rough surface) 5-2, inner permeable formwork permeable layer (smooth surface) 5-1, and secondary lining layer 6. This invention forms a drainage cushion layer by arranging double-layer permeable formwork between the initial support layer 2 and the secondary lining layer 6, which plays a certain role in guiding and draining external water. The drainage cushion layer formed by the double-layer permeable formwork is arranged in the following order: initial support side of the tunnel - permeable layer (smooth surface) - filter layer (rough surface) - filter layer (rough surface) - permeable layer (smooth surface) - concrete lining.

[0026] Both the outer permeable template fabric 4 and the inner permeable template fabric 5 are made of modified high molecular weight polypropylene fiber as the main raw material and are processed by special process. They are hydrophilic composite fiber structures with composite two-layer functions.

[0027] The double-layer permeable formwork fabric is prefabricated or can be factory-processed. After cutting the double-layer permeable formwork fabric to a size suitable for laying inside the tunnel wall, it is arranged in the following order: permeable layer (smooth surface) - filter layer (textured surface) - filter layer (textured surface) - permeable layer (smooth surface). The four sides are sealed using a heat-sealing method. Grouting holes 10 and drainage holes 11 are also provided on the double-layer permeable formwork fabric, and the openings of the grouting holes 10 and drainage holes 11 are also sealed using a heat-sealing method. Fixing patches 8 are attached to the outside of the double-layer permeable formwork fabric. When laying the double-layer permeable formwork fabric inside the tunnel, hot-melt adhesive nails 9 are used at the fixing patches 8 to fix the double-layer permeable formwork fabric to the initial support layer 2 for easy laying.

[0028] Preferably, both the outer permeable template fabric permeable layer (smooth surface) 4-1 and the inner permeable template fabric permeable layer (smooth surface) 5-1 are hydrophilic materials, and the average pore size of the air pores on the outer permeable template fabric permeable layer (smooth surface) 4-1 and the inner permeable template fabric permeable layer (smooth surface) 5-1 is 20-35μm. The permeable layer (smooth surface) is smooth and dense, allowing water and air to pass through in direct contact with concrete while preventing cement particles from passing through; it is permeable to water but not to mortar.

[0029] Preferably, the outer permeable formwork filter layer (rough surface) 4-2 and the inner permeable formwork filter layer (rough surface) 5-2 have a thickness of 1~2.5mm, possessing water retention and air permeability, with a water retention capacity greater than 0.25L / ㎡ and a drainage capacity greater than 0.4L / ㎡. The function of the filter layer (rough surface) is to retain appropriate moisture, allow excess moisture to seep out, and expel gas, keeping the concrete surface in a consistently moist environment.

[0030] The tunnel wall is provided with a drainage pipe 3 leading to the outside of the tunnel, and the opening of the drainage pipe 3 is located in the drainage hole 11.

[0031] like Figure 1 As shown, multiple independent drainage pipes 3 are installed in the tunnel wall. The independent drainage pipes 3 are connected by a drainage cushion layer to form a surface drainage network layer between the initial support and secondary lining of the tunnel, so as to collect and discharge groundwater in an organized manner.

[0032] This invention also proposes a construction method for the lining drainage structure of a hydraulic pressurized tunnel, applicable to the aforementioned lining drainage structure of a hydraulic pressurized tunnel, comprising the following steps: S1) Prepare double-layer permeable template fabric and test its performance indicators. Attach fixing patch 8 to the outside of the outer permeable template fabric 4.

[0033] Drainage holes 10 and grouting holes 11 are provided as needed for the double-layer permeable template fabric. The double-layer permeable template fabric and the drainage holes 10 and grouting holes 11 are sealed by heat fusion. Fixing patches 8 are attached to the outside of the double-layer permeable template fabric.

[0034] The inner permeable template cloth filter layer (rough surface) 5-2 is attached to the outer permeable template cloth filter layer (rough surface) 4-2, and the inner permeable template cloth permeable layer (smooth surface) 5-1 is oriented toward the secondary lining layer 6 to be poured.

[0035] Key point: The laying of double-layer permeable template fabric creates a stable drainage and ventilation cavity with a thickness of about 2-5mm between the two filter layers (textured surface). This cavity is the core space constituting the drainage underlayment network.

[0036] The modified polymer polypropylene fiber outer layer water permeable formwork cloth 4 and the inner layer water permeable formwork cloth 5 meet the design requirements, and are required to have a water permeable layer (smooth surface) and a filter layer (rough surface). The outer layer water permeable formwork cloth water permeable layer (smooth surface) 4-1 and the inner layer water permeable formwork cloth water permeable layer (smooth surface) 5-1 should ensure that the surface is smooth and dense, and the average pore size should be in the range of 20-35 μm. A simple grout test can be performed: cover the outer layer water permeable formwork cloth water permeable layer (smooth surface) 4-1 and the inner layer water permeable formwork cloth water permeable layer (smooth surface) 5-1 on the cement slurry, only water vapor should pass through and no cement particles should seep out.

[0037] The outer layer water permeable formwork cloth filter layer (rough surface) 4-2 and the inner layer water permeable formwork cloth filter layer (rough surface) 5-2 have a thickness of 1-2.5 mm and a loose structure. The water retention capacity is greater than 0.25 L / m2, and the drainage capacity is greater than 0.4 L / m2.

[0038] S2) Remove the protrusions on the surface of the primary support layer 2, and use mortar to level the pits on the surface of the primary support layer 2.

[0039] The primary support layer 2 is usually a shotcrete surface, which usually has sharp corners, steel bars, iron wires and other protrusions. After leveling with mortar, the base surface should be smooth and free of hidden dangers that may pierce or severely damage the formwork cloth.

[0040] S3) Drill holes in the tunnel wall and install the drainage pipe 3.

[0041] The drilling and installation of the tunnel drainage pipe 3 are usually carried out in the following steps, and the whole process needs to ensure smooth drainage, stable hole wall and anti-blocking: First, the construction opportunity and preparation; Second, drill holes in the wall; Third, install and fix the drainage pipe 3; Fourth, handle and accept the orifice, groove or punch the pipe body of the drainage pipe 3, and wrap the geotextile at the orifice of the drainage pipe 3 to form a filter layer.

[0042] S4) Pass the drainage hole 11 of the double-layer water permeable formwork cloth through the drainage pipe 3, and use hot melt glue nails 9 to fix the patch 8 together with the double-layer water permeable formwork cloth on the surface of the primary support layer 2.

[0043] Preferably, a layer of geotextile is arranged between the primary support layer 2 and the outer layer water permeable formwork cloth 4 before laying the outer layer water permeable formwork cloth 4.

[0044] The hot melt glue nails 9 are compatible with the double-layer water permeable formwork cloth and the concrete surface.

[0045] S5) Perform secondary lining layer 6 construction and pouring.

[0046] Under the lateral pressure generated by the secondary lining concrete vibration, the water-permeable layer (smooth surface) 5-1 of the inner water-permeable formwork cloth plays a key role of "water permeable and mortar impermeable", and exhausts and drains, i.e. the bubbles and part of the excess free water in the concrete, under the pressure, pass through the air-permeable holes of the water-permeable layer (smooth surface) layer and enter the cavity formed by the two filter layers (rough surface).

[0047] Due to the effective blocking of the cement particles, the water-cement ratio of the surface layer of the secondary lining concrete is reduced, and the structure is more compact, thereby significantly improving the surface strength, impermeability and wear resistance of the secondary lining layer 6. At the same time, the water-permeable layer (smooth surface) 5-1 of the inner water-permeable formwork cloth also prevents the cement mortar from seeping into and blocking the drainage cavity, and ensures the long-term effectiveness of the drainage system.

[0048] It should be noted that when the secondary lining layer 6 is constructed, the binding operation of the secondary lining steel bars is carried out on the laid double-layer water-permeable formwork cloth, and the operation should be carefully operated to avoid the steel bar end piercing the formwork cloth, and a protective pad can be provided at the contact point of the steel bar and the formwork cloth if necessary.

[0049] Preferably, when the tunnel secondary lining layer 6 is constructed, the outer water-permeable formwork cloth 4 and the inner water-permeable formwork cloth 5 are laid in a proper range at the top of the tunnel, wherein the outer water-permeable formwork cloth 4 faces the initial support layer 2 of the outer tunnel, and the water-permeable layer (smooth surface) 5-1 of the inner water-permeable formwork cloth faces the tunnel secondary lining side, i.e. arranged in the order of tunnel initial support layer - water-permeable layer (smooth surface) - filter layer (rough surface) - filter layer (rough surface) - water-permeable layer (smooth surface) - tunnel secondary lining. By forming a drainage cushion layer between the outer water-permeable formwork cloth 4 and the inner water-permeable formwork cloth 5, the external water can be collected to other drainage holes through the drainage cushion layer and finally drained out, solving the problem of high external water caused by the blockage or failure of individual drainage holes.

[0050] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above embodiments, and any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods and shall be included in the protection scope of the present application.

Claims

1. A lining drainage structure for a pressurized hydraulic tunnel, characterized in that: It includes a double-layer permeable template cloth set between the initial support layer (2) and the secondary lining layer (6) of the tunnel wall, the double-layer permeable template cloth including an outer permeable template cloth (4) and an inner permeable template cloth (5); and the double-layer permeable template cloth is sealed at all four sides; The outer permeable template fabric (4) includes an outer permeable template fabric permeable layer (4-1) and an outer permeable template fabric filter layer (4-2), and the outer permeable template fabric permeable layer (4-1) is fixed and attached to the surface of the initial support layer (2); The inner permeable template fabric (5) includes an inner permeable template fabric permeable layer (5-1) and an inner permeable template fabric filter layer (5-2), and the inner permeable template fabric permeable layer (5-1) is fixed and attached to the surface of the secondary lining layer (6), and the inner permeable template fabric filter layer (5-2) is attached to the outer permeable template fabric filter layer (4-2); Both the outer permeable template fabric permeable layer (4-1) and the inner permeable template fabric permeable layer (5-1) have permeable pores for water and air permeability, but without slurry permeability; both the outer permeable template fabric filter layer (4-2) and the inner permeable template fabric filter layer (5-2) are loose structures with water retention and air permeability, and a drainage and air permeable cavity is formed between the inner permeable template fabric filter layer (5-2) and the outer permeable template fabric filter layer (4-2); The double-layer permeable template fabric has grouting holes (10) and drainage holes (11) that penetrate from the inside out, and the grouting holes (10) and drainage holes (11) are sealed around their openings. The tunnel wall is provided with a drainage pipe (3) leading to the outside of the tunnel, and the opening of the drainage pipe (3) is located in the drainage hole (11).

2. The lining drainage structure for a pressurized hydraulic tunnel according to claim 1, characterized in that: Both the outer permeable template fabric permeable layer (4-1) and the inner permeable template fabric permeable layer (5-1) are hydrophilic materials, and the average pore size of the air pores on the outer permeable template fabric permeable layer (4-1) and the inner permeable template fabric permeable layer (5-1) is 20-35μm.

3. The lining drainage structure for a pressurized hydraulic tunnel according to claim 2, characterized in that: The outer permeable template fabric filter layer (4-2) and the inner permeable template fabric filter layer (5-2) are 1~2.5mm thick, and have water retention and air permeability properties, with a water retention capacity greater than 0.25L / ㎡ and a drainage capacity greater than 0.4L / ㎡.

4. The lining drainage structure for a pressurized hydraulic tunnel according to claim 3, characterized in that: Both the outer permeable template fabric (4) and the inner permeable template fabric (5) are made of modified polymer polypropylene fiber as the main raw material.

5. A construction method for the lining drainage structure of a hydraulic pressurized tunnel, applicable to the lining drainage structure of a hydraulic pressurized tunnel as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1) Prepare double-layer permeable template cloth and test its performance indicators. Attach fixing patch (8) to the outside of the outer permeable template cloth (4). S2) Remove the protrusions on the surface of the initial support layer (2) and level the pits on the surface of the initial support layer (2) with mortar; S3) Drill holes in the tunnel wall and install drainage pipes (3); S4) Pass the drainage hole (11) of the double-layer permeable template cloth through the drainage pipe (3), and use hot melt glue nails (9) to fix the fixing patch (8) together with the double-layer permeable template cloth to the surface of the initial support layer (2); S5) The secondary lining layer (6) is poured.

6. The construction method for the lining drainage structure of a pressurized hydraulic tunnel according to claim 5, characterized in that: In S1), the double-layer permeable template fabric is sealed around its perimeter using a heat-sealing method.

7. The construction method for the lining drainage structure of a pressurized hydraulic tunnel according to claim 6, characterized in that: In S3), geotextile nonwoven fabric is wrapped around the opening of the drainage pipe (3) to form a filter layer.

8. The construction method for the lining drainage structure of a pressurized hydraulic tunnel according to claim 7, characterized in that: In S4), the hot melt adhesive nail (9) is compatible with the double-layer permeable template cloth and the concrete surface.

9. The construction method for the lining drainage structure of a pressurized hydraulic tunnel according to claim 8, characterized in that: In S4), before laying the double-layer permeable template fabric, a geotextile is set between the initial support layer (2) and the double-layer permeable template fabric.

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