A tunnel cold-proof and heat-insulating system for high-altitude and severe cold areas and its construction method

Abstract

The present invention provides a tunnel cold-proof and heat-insulating system for high-altitude and severe cold areas and a construction method thereof, which belongs to the technical field of tunnel construction and frost damage prevention and control in cold areas, and is for solving the problem that the structure of tunnels crossing dangerous slopes in high-altitude and severe cold areas is damaged due to frost damage. The tunnel cold-proof and heat-insulating system for high-altitude and severe cold areas includes a tunnel insulation layer and a drainage structure. The tunnel insulation layer includes a secondary lining, geotextile A, a waterproof board, geotextile B and initial support arranged from the inside to the outside; the drainage system includes a drainage mechanism behind the lining and a central drainage pipe. The drainage mechanism behind the lining is arranged circumferentially along the tunnel arch wall, and the central drainage pipe is laid in the middle position of the bottom of the tunnel. The tunnel insulation layer greatly reduces the entry of surrounding rock water into the insulation lining structure, and once it enters, it can be discharged in time. At the same time, the double-layer insulation structure is adopted, which can greatly reduce the degree of low temperature intrusion, realize the rapid construction of the tunnel insulation layer in high-altitude and cold areas, and effectively increase the service life of the insulation measures.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel construction and frost damage prevention and control in cold regions, and specifically relates to a tunnel cold-proof and heat-insulating system in high-altitude and severely cold regions and a construction method thereof. Background Art

[0002] High-altitude cold regions have significant climatic characteristics, which are mostly manifested as perennial low temperatures and perennial frozen soil. At present, cold-region tunnels that pass through perennial or other frozen soil sections often suffer from frost damage at the entrance section. The principle of cold-proof and thermal insulation design for cold-region tunnels is to reduce the disturbance of the soil (rock) around the tunnel site, so as to avoid causing a large-scale construction melting zone, resulting in tunnel thawing and even collapse. When crossing dangerous slopes at high altitudes, how to maintain the stability of the soil while performing reasonable construction has attracted widespread attention. Therefore, in the construction of such tunnels, it is not advisable to use deep-buried central ditches and cold-proof drainage holes below them. Shallow buried and surface cold-proof and thermal insulation measures should be set up, such as insulation ditches, insulation layers and drainage systems behind them. Such tunnels are generally located in extremely cold climates, and the surrounding rock grade is poor, which is easily disturbed by construction. The anti-freezing measures of the drainage system are extremely high. If the drainage system fails due to freezing, lining leakage, water accumulation and freezing at the bottom of the tunnel, lining cracking and other freezing damages will occur, which seriously threaten the operation of the tunnel.

[0003] High-altitude cold tunnels are located in plateaus, with fragile ecology, and are in a cold and snowy climate environment all year round. The effective construction time is short. In addition, such areas are generally located in earthquake zones, and deformation problems are prominent during construction and operation. Conventional insulation measures do not meet the construction requirements of such tunnels. Once improperly handled, huge economic losses will be caused. Whether the construction of the insulation layer in the tunnel is effective directly affects the normal operation and service life of the tunnel. Therefore, how to adopt effective measures during the construction of these tunnels and achieve the expected effect during use is a difficult problem that the engineering community urgently needs to solve. The Chinese invention patent (CN116753024 A) provides a heated tunnel drainage system, which meets the antifreeze needs of drainage pipes to a certain extent, but the heating device is difficult to install during construction and has a limited service life; the Chinese invention patent (CN 113482672 A) provides an antifreeze insulation heating system, which uses a heating system to heat the tunnel to meet the antifreeze needs of the tunnel, but the heating system consumes a lot of energy. Considering that the cold zone tunnels are located in remote environments and energy supply is inconvenient, the applicability of the insulation system needs to be studied. From a construction perspective, in order to solve the problem of frost damage to the structure of tunnels crossing dangerous slopes in high-altitude cold areas, it is very important to invent a cold-proof insulation layer system for cold-resistant tunnels that has a reasonable structure, is easy to use and takes economic costs into account. Summary of the invention

[0004] The present invention is dedicated to addressing the defects and deficiencies of the prior art, and provides a tunnel cold-proof and heat-insulating system for high-altitude and severe cold areas and a construction method thereof. Considering the climatic characteristics of high-altitude and severe cold areas, the change in temperature is related to the altitude, that is, the temperature drops by about 0.6°C for every 100-meter increase in altitude. The present invention is suitable for severe cold areas with an altitude of more than 3,000 meters. Under the premise of ensuring the stability of the surrounding rock of the tunnel chamber and controllable temperature, it effectively prevents the occurrence of diseases in severe cold tunnels, especially in the tunnel portal section, and ensures the construction quality under adverse geological conditions and the normal use of the tunnel.

[0005] To achieve the above object, one object of the present invention is to provide a tunnel cold protection and heat preservation system for high altitude and severe cold areas, the heat preservation system comprising a tunnel heat preservation layer and a drainage system, wherein:

[0006] The tunnel insulation layer includes secondary lining, geotextile A, waterproof board, geotextile B and initial support, which are arranged from the inside to the outside;

[0007] The drainage system includes a drainage mechanism behind the lining and a central drainage pipe. The drainage mechanism behind the lining is arranged circumferentially along the tunnel arch wall to discharge water seepage from the arch wall surrounding rock; the central drainage pipe is laid in the middle position of the tunnel bottom.

[0008] On the basis of the above technical solution, the tunnel insulation layer also includes a rubber-plastic insulation layer, which is arranged on the arch and the side wall and is located between the geotextile A and the waterproof board.

[0009] On the basis of the above technical solution, further, the tunnel insulation layer also includes a pre-embedded waterproof board, which is arranged at the tunnel arch foot and located in the secondary lining.

[0010] On the basis of the above technical scheme, further, the drainage mechanism behind the lining includes an annular drainage pipe, a vertical drainage pipe and a longitudinal drainage pipe. The annular drainage pipe is connected to the vertical drainage pipe through a heated connecting pipe to form a mesh structure. The mesh structure is arranged circumferentially along the tunnel arch wall, and the longitudinal drainage pipes are connected at both ends of the mesh structure to discharge the seepage of the arch wall surrounding rock through the longitudinal drainage pipe.

[0011] On the basis of the above technical solution, further, the heating connecting tube is a cross-shaped tube shell, a carbon fiber heating film is wrapped along the inner wall of the cross-shaped tube shell, a winding heating wire is arranged inside the interface section at both ends of the horizontal tube shell of the cross-shaped tube shell, a vertical heating wire is arranged in the vertical tube shell of the cross-shaped tube shell, and sensors are arranged at both ends of the vertical heating wire.

[0012] On the basis of the above technical solution, further, the interface sections at both ends of the horizontal tube shell of the cross-shaped tube shell are embedded with insulator interfaces, the annular drainage pipe is threadedly connected to the insulator interface, and the end of the vertical guide pipe is directly inserted into the vertical drainage pipe interface of the heating connecting pipe by wrapping non-woven fabric.

[0013] On the basis of the above technical solution, further, an asphalt geotextile insulation layer is filled around the central drainage pipe, and heat exchange pipes are arranged on both sides of the central drainage pipe. The heat exchange pipes are connected to the heat pump machine, and the heat pump machine is connected to the longitudinal drainage pipe through a transverse guide pipe.

[0014] Another object of the present invention is to provide a method for constructing a tunnel cold-proof and heat-insulating system in a high-altitude cold region, comprising the following steps:

[0015] Step 1: Check the degree of unevenness of the surrounding rock surface. If the unevenness is too large, it is necessary to perform flatness treatment. If the rock surface is cracked too large or there are large cavities, grouting treatment is required. If the rock surface is evenly undulating, spray 3 to 5 cm of concrete on the rock surface in advance to facilitate the installation of drainage pipes.

[0016] Step 2: Install the annular drainage pipe, vertical drainage pipe and heating connection pipe. Install the annular drainage pipe and vertical drainage pipe to the rock surface through rivets and splice them through the heating connection pipe. Arrange several temperature sensors at the reserved leakage point of the tunnel vault and pre-embed the wires. According to the preliminary survey, 1 to 3 sensors are arranged for different cross-sections. The number can be increased to a certain extent in areas with obvious temperature changes and developed water veins. The heating connection pipe is wrapped with a rubber outer skin, and hot-melt gaskets are set on the front and back, which are bonded with self-adhesive tape to prevent frost heave from damaging the heating structure. Then spray concrete is applied to completely cover the drainage pipe to form the initial support of spray concrete + drainage pipe.

[0017] Step 3: Apply the insulation layer structure, lay geotextile B on the surface of the shotcrete, and fix it with masonry nails, which are directly driven into the initial support. Then apply the waterproof board and rubber-plastic insulation layer in turn, use self-adhesive tape and hot-melt gasket to bond the front of the rubber-plastic insulation layer to the waterproof board as a whole, and adjust the deformable connection groove according to the shape of the tunnel section to make the rubber-plastic insulation layer close to the waterproof board.

[0018] Step 4: Install the longitudinal drainage pipe and construct it at the same time as the insulation layer structure, from bottom to top, using it as the concrete base, longitudinal drainage pipe and shotcrete, and add geotextile A and waterproof board on the surface of the shotcrete.

[0019] Step 5: Install the transverse guide pipe, which is directly connected to the longitudinal drainage pipe to drain the water behind the lining into the central drainage ditch. Some transverse guide pipes are connected to the preset heat pump, and the water flows through the heat pump and heat exchange pipe and then drains into the central drainage ditch.

[0020] Step 6: Finally, apply the secondary lining using plain concrete or reinforced concrete with anti-cracking and waterproof expansion agent.

[0021] In step 1, in order to make the drainage pipe better fit the rock surface, 2 to 5 cm thick concrete should be sprayed before excavation to ensure the flatness of the surrounding rock. And the drainage pipe should be laid at the preset leakage point.

[0022] In step 2, the outside of the heating connecting pipe is wrapped with a rubber outer skin, and hot-melt gaskets are set on the front and back sides, and are bonded by self-adhesive tape.

[0023] In step 3, hot melt adhesive pads and gaskets are added between masonry nails and geotextile B to prevent the masonry nails from damaging the waterproof board. Special welding hot melt adhesive is used between waterproof boards, the bonding part is not less than 100mm, and the bonding peel strength is not less than 80% of the original tensile strength.

[0024] In step 4, the longitudinal drainage pipe is connected to the transverse and longitudinal diversion pipes, the waterproof board at the arch foot is overlapped, the length is ≥100mm, and it is connected to the embedded waterproof board in the secondary lining. The embedded waterproof board can be used as the first waterproofing of the construction joint, and the rubber sealing tape is set in the construction joint as the second waterproofing.

[0025] In step 5, the water in the transverse guide pipe flows through the heat pump into the heat exchange pipe, flows back to the heat pump after passing through the heat exchange pipe, and finally flows into the central drainage pipe. A temperature sensor is provided in the heat pump, and when the temperature is below 0°C, the heat pump starts to work.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The present invention adopts double insulation measures and adopts a composite insulation method combining active and passive insulation, which has better insulation and antifreeze effects and is easier to control.

[0028] 2. The tunnel insulation layer provided by the present invention greatly reduces the entry of surrounding rock water into the insulation lining structure, and can be discharged in time once it enters. At the same time, the double-layer insulation structure is adopted, which can greatly reduce the degree of low temperature intrusion. The rubber-plastic layer insulation structure has the function of secondary waterproofing while insulating, which greatly reduces the harm of frost heave, realizes the rapid construction of tunnel insulation layer in high-cold areas, and effectively increases the service life of insulation measures.

[0029] 3. The present invention adopts an active thermal insulation structure to centrally heat the annular drainage pipe and part of the central drainage pipe, actively change the temperature conditions of the tunnel antifreeze section, and realize real-time monitoring and automatic control of the temperature behind the lining of the high-cold tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the construction of the tunnel cold-proof and heat-insulating structure in the present invention.

[0031] Figure 2 This is a schematic diagram of the construction of the local cold-proof drainage structure at the tunnel arch foot in the present invention.

[0032] Figure 3 This is the construction drawing for the local drainage pipe layout of the tunnel in the present invention.

[0033] Figure 4 The invention provides a construction drawing of the thermal insulation structure at the location where masonry nails are driven into.

[0034] Figure 5 It is a schematic diagram of the connection of the heating type connecting pipe in the present invention.

[0035] Figure 6 It is a cross-sectional view of the heating connecting pipe in the present invention.

[0036] Figure 7 It is a schematic diagram of the position of the drainage pipe in the present invention.

[0037] Figure 8 This is a schematic diagram of the heat pump machine connected to the drainage pipe in the present invention.

[0038] Fig. 9 This is a schematic diagram of the layout of the heat exchange tubes in the present invention.

[0039] Fig.10 This is a schematic diagram of the construction of the water stop strip at the deformed joint of the present invention.

[0040] Among them, 1. Heating connecting pipe; 101. Vertical heating wire; 102. Insulator; 103. Carbon fiber heating film; 104. Wrapped heating wire; 105. Annular drainage pipe interface section; 106. Sensor; 107. Vertical drainage pipe interface; 2. Annular drainage pipe; 3. Vertical guide pipe; 4. Longitudinal drainage pipe; 5. Central drainage pipe; 6. Horizontal guide pipe; 7. Heat pump; 8. Water inlet pipe; 9. Drainage pipe; 10. Water outlet pipe. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0042] Embodiment 1:

[0043] This embodiment provides a tunnel cold protection and heat preservation system for high-altitude and severe cold areas, which includes a tunnel insulation layer structure and a drainage structure, specifically:

[0044] Insulation layer structure Figure 1 , Figure 2 , Figure 3 , Figure 4 shown.

[0045] The tunnel insulation layer adopts an integrated structure, such as Figure 1 As shown in the figure, from inside to outside, it specifically includes: secondary lining (plain concrete or reinforced concrete with anti-cracking and waterproof expansion agent), geotextile A, rubber-plastic insulation layer (only laid on the vault and side wall), waterproof board, geotextile B and initial support (sprayed concrete). The tunnel insulation layer is set along the entire length of the tunnel. The structure of outer waterproof layer and inner insulation layer can effectively reduce the impact of low temperature and prevent frost damage. Optionally, geotextile B between rubber-plastic insulation layer and secondary lining can be replaced with a 2cm cement mortar leveling layer.

[0046] The waterproof board adopts EVA waterproof board.

[0047] The tunnel arch foot requires special treatment due to the longitudinal drainage pipe 4. Figure 2 As shown, geotextile B and EVA waterproof board are installed on the surface of the arch foot. The EVA waterproof boards are overlapped, and the overlap length is ≥100mm. In addition, waterproof board needs to be embedded in the secondary lining position, and the embedded length is ≥250mm. Furthermore, rubber sealing belt needs to be installed at the construction joint of the arch foot.

[0048] like Figure 3 , Figure 4 As shown, the geotextile B between the EVA waterproof board and the initial support needs to be fixed with masonry nails. The masonry nails are driven into the initial support through gaskets and hot melt adhesive pads, and cannot be driven into the surrounding rock. Manually weld the EVA waterproof board, and the two EVA waterproof boards are connected by hot melt adhesive. The connection part is not less than 100mm, and the bonding peel strength of the two EVA waterproof boards is not less than 80% of the tensile strength of the waterproof board. Optionally, the protruding parts of the masonry nails can be leveled with cement mortar, or the insulation layer can be corrected and directly bonded to the drainage board.

[0049] The drainage system of the high-altitude tunnel includes the drainage system behind the lining and the central drainage pipe 5, see Figure 5 , Figure 6 , Figure 7 , Figure 8 as well as Fig. 9 .

[0050] The drainage system behind the lining includes an annular drainage pipe 2, a vertical drainage pipe 3, a longitudinal drainage pipe 4 and a heating connecting pipe 1. The annular drainage pipe 2, the vertical drainage pipe 3 and the heating connecting pipe 1 are arranged annularly along the tunnel arch wall. The annular drainage pipe 2 is connected to the vertical drainage pipe 3 through the heating connecting pipe 1, and the vertical drainage pipe 3 is connected to the longitudinal drainage pipe 4 to discharge the seepage of the arch wall surrounding rock.

[0051] The annular drainage pipe 2, vertical flow guide pipe 3 and heating connection pipe 1 are directly anchored into the surrounding rock and serve as the initial support together with the shotcrete. Figure 3Optionally, the surrounding rock surface needs to be pre-chiselled or pre-sprayed with 3~5cm of concrete to ensure the normal installation of the drainage pipe.

[0052] The annular drainage pipe 2 is connected to the vertical flow guide pipe 3 through a heating connecting pipe 1. Figure 5 The annular drainage pipe 2 is a double-walled single-sided multi-hole corrugated pipe, and a drainage pipe is arranged at the preset leakage point position to facilitate the surrounding rock water to flow into the pipe body. The specific layout position is as follows: (1) For V, IV, and V+ grade surrounding rocks, one leakage point is arranged every 3 to 5 meters, and the leakage point at a certain place increases according to the change of water content; (2) For III grade surrounding rocks, one leakage point is arranged every 6 meters, and the leakage point at a certain place increases according to the change of water content.

[0053] The vertical flow guide pipe 3 is a corrugated pipe or a PP pipe wrapped with a heat-insulating material.

[0054] The annular drainage pipe 2 is arranged annularly along the arch wall, and together with the vertical guide pipe 3 and the heating connecting pipe 1, forms a heated annular drainage system, which improves the antifreeze effect of the tunnel through active heating.

[0055] The temperature sensor is arranged on the tunnel vault, connected to the heating connecting pipe 1 and the heat pump 7, controls the operation of the heating device, and forms an automatic heat preservation and heating system. According to the temperature monitoring data, 1 to 3 sensors can be arranged in a single cross section, and the number can be increased to a certain extent in areas with large temperature amplitudes.

[0056] Heating connecting pipe 1 structure, see Figure 6 Considering that the annular drainage pipe 2 is set along the entire length of the tunnel and is the main drainage pipe of the tunnel arch wall, the connection port is set to be threaded to prevent slipping. The interface section is made of insulating material to prevent moisture from penetrating into the structure and causing the heating connection pipe 1 to burn out. The vertical guide pipe 3 only has a diversion function. It is wrapped with non-woven fabric and directly inserted into the vertical drainage pipe interface 107. The pipe mouth section still uses insulating material.

[0057] The internal structure of the heating connecting tube 1 includes a winding heating wire 104, a vertical heating wire 101, an electric heating liquid and a carbon fiber heating film 103. The winding heating wire 104, the vertical heating wire 101 and the electric heating liquid are all in the connecting tube shell, the carbon fiber heating film 103 wraps the inner shell, and the outermost layer is the outer tube wall.

[0058] The winding heating wire 104 is arranged at the annular drainage pipe interface section 105. When the temperature sensed by the temperature sensor is less than 0°C, the winding heating wire 104 starts to work and is used to heat the passing water. The vertical heating wire 101 is arranged at the bottom of the connecting pipe, and sensors 106 are arranged at both ends. An insulator 102 is arranged at its end. The carbon fiber heating film 103 wraps the inner shell. When the temperature sensed by the connecting pipe is less than 0°C, the vertical heating wire 101 and the carbon fiber heating film 103 start to work at the same time.

[0059] Considering the cost and construction quality, the fixed point heating method is used to heat the ring and vertical connection points. The heating connection pipes are arranged at intervals. The specific positions are shown in Figure 7 The active insulation measures focus on actively heating areas prone to freezing of drainage pipes, such as behind high-altitude tunnel linings, geological structure fractures, and water veins, to effectively reduce freezing of drainage pipes caused by low temperatures.

[0060] The central drainage pipe 5 is set along the entire length of the middle position of the tunnel bottom, with a concrete cushion at the bottom, 3-5 cm gravel filled on the top, and covered with geotextile. The central drainage pipe 5 is surrounded by an asphalt + geotextile insulation layer.

[0061] Optionally, heat exchange tubes may be added based on preliminary survey conditions.

[0062] The longitudinal drainage pipe 4 is connected to the central drainage ditch via the transverse guide pipe 6 to introduce the surrounding rock water into the central drainage ditch.

[0063] Optionally, if a heat exchange pipe is added, a heat pump 7 is added between the longitudinal drainage pipe 4 and the central drainage pipe 5 .

[0064] See Figure 8 , the water in the longitudinal drainage pipe 4 is introduced into the heat pump 7 through the transverse guide pipe 6. After being processed by the heat pump 7, part of the water flows into the heat exchange pipe through the water inlet pipe 8, and the rest of the water flows directly into the central drainage pipe 5; after the water flows in the heat exchange pipe circulate (the heat exchange pipe includes the water inlet pipe 8 and the water outlet pipe 10, both of which are S-shaped), it flows back to the heat pump 7 through the water outlet pipe 10, see Fig. 9 , and finally discharged into the central drain pipe 5 through the drain pipe 9.

[0065] Optionally, in the case of adding heat exchange pipes, considering the project cost and construction progress, it is not necessary to add heat pumps 7 to all the transverse guide pipes 6. According to the preliminary survey, only in the location where the water veins are developed and the burial depth is shallow, the heat exchange pipes are arranged in the area and at intervals. The length of the heat exchange pipes needs to be to the next drainage pipe position. The arrangement method is shown in Fig. 9 .

[0066] Embodiment 2:

[0067] This embodiment provides a construction method for a cold-proof and heat-insulating layer structure in a high-altitude cold region based on the first embodiment, comprising the following steps:

[0068] Step 1: Check the concave and convex degree of the surrounding rock surface. If the concave and convex degree is too large, it is necessary to perform flatness treatment. If the rock surface has too large cracks or there are large cavities, grouting treatment is required; if the rock surface is evenly undulating, 3~5cm of concrete can be sprayed on the rock surface in advance to facilitate the installation of drainage pipes.

[0069] Step 2: Install the annular drainage pipe 2, vertical drainage pipe 3 and heating connection pipe 1. Install the annular drainage pipe 2 and vertical drainage pipe 3 to the rock surface through rivets and splice them through the heating connection pipe 1. Several temperature sensors are laid out at the reserved leakage point on the arch, and wires are pre-buried. Different cross-sections are laid out 1 to 3 according to the preliminary survey. The number can be increased to a certain extent in areas with obvious temperature changes and developed water veins. The heating connection pipe 1 is wrapped with a rubber outer skin, and hot-melt gaskets are set on the front and back, which are bonded with self-adhesive tape to prevent frost heave from damaging the heating structure. Then sprayed concrete is applied to completely cover the drainage pipe to form the initial support of sprayed concrete + drainage pipe.

[0070] Step 3: Apply the insulation layer structure, lay geotextile B on the surface of the shotcrete, and fix it with masonry nails, which are directly driven into the initial support. Then apply the EVA waterproof board and rubber-plastic insulation layer in turn, use self-adhesive tape and hot-melt gasket to bond the front of the insulation layer to the waterproof board as a whole, and adjust the deformable connection groove according to the shape of the tunnel section to make the insulation layer and the waterproof board close together.

[0071] Step 4: Install the longitudinal drainage pipe 4, which is constructed simultaneously with the insulation layer structure. From bottom to top, the concrete base, longitudinal drainage pipe 4 and shotcrete are installed, and geotextile A and EVA waterproof board are added to the surface of the shotcrete.

[0072] Step 5: Install the transverse guide pipe 6, which is directly connected to the longitudinal drainage pipe 4 to drain the water behind the lining into the central drainage ditch. Some transverse guide pipes 6 are connected to the preset heat pump 7, and the water flows through the heat pump 7 and the heat exchange pipe and then drains into the central drainage ditch.

[0073] Step 6: Finally, apply the secondary lining using plain concrete or reinforced concrete with anti-cracking and waterproof expansion agent.

[0074] In step 1, in order to make the drainage pipe better fit the rock surface, 2 to 5 cm thick concrete should be sprayed before excavation to ensure the flatness of the surrounding rock. And the drainage pipe should be laid at the preset leakage point.

[0075] In step 2, the heating connecting pipe 1 is wrapped with a rubber outer skin, and hot-melt gaskets are arranged on the front and back sides, and are bonded by self-adhesive tape.

[0076] In step 3, hot melt adhesive pads and gaskets are added between masonry nails and geotextile B to prevent the masonry nails from damaging the waterproof board. Special welding hot melt adhesive is used between waterproof boards, the bonding part is not less than 100mm, and the bonding peel strength is not less than 80% of the original tensile strength.

[0077] In step 4, the longitudinal drainage pipe 4 is connected to the transverse and longitudinal guide pipes, the waterproof board at the arch foot is overlapped, the length is ≥100mm, and it is connected to the embedded waterproof board in the secondary lining. The embedded waterproof board can be used as the first waterproofing of the construction joint, and a rubber sealing tape is set in the construction joint as the second waterproofing.

[0078] In step 5, the water in the transverse flow guide pipe 6 flows through the heat pump 7 into the heat exchange pipe, flows back to the heat pump 7 after passing through the heat exchange pipe, and finally flows into the central drainage pipe 5. A temperature sensor is provided in the heat pump 7, and when the temperature is lower than 0°C, the heat pump 7 starts to work.

[0079] At the deformed joint position, water stop strips need to be added, such as Fig.10 shown.

[0080] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, so that those skilled in the art can understand and apply the present invention. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art of the present invention, some simple deductions or substitutions can be made without departing from the concept of the present invention, without creative work. Therefore, simple improvements made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the scope of protection of the present invention.

Claims

1. A tunnel cold protection and heat preservation system for high altitude and severe cold areas, characterized in that: The insulation system includes the tunnel insulation layer and drainage system, including: The tunnel insulation layer includes secondary lining, geotextile A, waterproof board, geotextile B and initial support, which are arranged from the inside to the outside; The drainage system includes a drainage mechanism behind the lining and a central drainage pipe. The drainage mechanism behind the lining is arranged circumferentially along the tunnel arch wall, and the central drainage pipe is laid in the middle of the tunnel bottom. The drainage mechanism behind the lining includes an annular drainage pipe, a vertical drainage pipe and a longitudinal drainage pipe. The annular drainage pipe is connected to the vertical drainage pipe through a heated connecting pipe to form a mesh structure. The mesh structure is arranged along the tunnel arch wall in an annular direction, and the longitudinal drainage pipes are connected at both ends of the mesh structure to discharge the seepage water from the arch wall surrounding rock through the longitudinal drainage pipes. The heating connecting pipe is a cross-shaped tube shell, and a carbon fiber heating film is wrapped along the inner wall of the cross-shaped tube shell. A winding heating wire is arranged inside the interface section at both ends of the horizontal tube shell of the cross-shaped tube shell, and a vertical heating wire is arranged in the vertical tube shell of the cross-shaped tube shell. Inductors are arranged at both ends of the vertical heating wire. Insulator interfaces are embedded in the interface sections at both ends of the horizontal tube shell of the cross-shaped tube shell, the annular drainage pipe is threadedly connected to the insulator interface, and the end of the vertical flow guide pipe is directly inserted into the vertical drainage pipe interface of the heating connecting pipe by wrapping non-woven fabric.

2. The cold-proof and heat-insulating system for tunnels in high-altitude and severe cold regions according to claim 1 is characterized in that: The tunnel insulation layer also includes a rubber-plastic insulation layer, which is arranged on the arch and the side wall and is located between the geotextile A and the waterproof board.

3. The cold-proof and heat-insulating system for tunnels in high-altitude and severe cold regions according to claim 2 is characterized in that: The tunnel insulation layer also includes a pre-buried waterproof board, which is arranged at the tunnel arch foot and located in the secondary lining.

4. The cold-proof and heat-insulating system for tunnels in high-altitude and severe cold regions according to claim 3 is characterized in that: The central drainage pipe is filled with an asphalt geotextile insulation layer around it, and heat exchange pipes are arranged on both sides of the central drainage pipe. The heat exchange pipes are connected to the heat pump machine, and the heat pump machine is connected to the longitudinal drainage pipe through a transverse guide pipe.

5. A method for constructing a tunnel cold-proof and heat-insulating system in a high-altitude cold region, characterized in that: The construction method is used to construct a tunnel cold-proof and heat-insulating system for high-altitude and severe cold areas as described in claim 4, and the construction method comprises the following steps: Step 1: Check the concave and convex degree of the surrounding rock surface and perform flatness treatment; Step 2: Install the annular drainage pipe, vertical guide pipe and heating connecting pipe, lay out the temperature sensor at the reserved leakage point of the tunnel vault, and pre-embed the wire, then apply shotcrete to completely cover the annular drainage pipe to form the initial support of shotcrete + drainage pipe; Step 3: Apply the tunnel insulation layer, lay geotextile B on the surface of the shotcrete, and fix it with masonry nails, which are directly driven into the initial support. Then apply the waterproof board and rubber-plastic insulation layer in sequence, and use self-adhesive tape and hot-melt gasket to bond the front of the rubber-plastic insulation layer to the waterproof board as a whole. Adjust the deformable connection groove according to the cross-sectional shape of the tunnel to make the rubber-plastic insulation layer and the waterproof board close together; Step 4: Install the longitudinal drainage pipe and the tunnel insulation layer at the same time, from bottom to top, using this as the concrete base, longitudinal drainage pipe and shotcrete, and add geotextile A and waterproof board on the surface of the shotcrete; Step 5: Install the transverse guide pipe, which is connected to the longitudinal drainage pipe to drain the water behind the lining into the central drainage pipe. The transverse guide pipe is also connected to the heat pump. After the water flows through the heat pump and the heat exchange tube, it is discharged into the central drainage pipe. Step 6: Finally, apply the secondary lining using plain concrete or reinforced concrete with anti-cracking and waterproof expansion agent.

6. The method for constructing a tunnel cold-proof and heat-insulating system in a high-altitude cold region according to claim 5, characterized in that: In step 4, the longitudinal drainage pipe is connected to the transverse guide pipe and the longitudinal guide pipe, the tunnel arch foot is overlapped with a waterproof board, and connected to the embedded waterproof board in the secondary lining. The embedded waterproof board serves as the first waterproofing of the construction joint, and a rubber sealing tape is set in the construction joint as the second waterproofing.

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