Shallow-buried anti-freezing section railway tunnel structure in alpine region and heating system

Abstract

The utility model discloses an alpine region shallow-buried anti-freezing section railway tunnel structure and a heating system, which comprise a thermal insulation mortar layer attached to surrounding rock, and a concrete primary support layer, a drainage pipe, non-woven geotechnical cloth, an EVA (Ethylene Vinyl Acetate) waterproof plate, a polyurethane thermal insulation plate and a reinforced concrete secondary lining layer are sequentially attached to the other side of the thermal insulation mortar layer. A drainage ditch is formed in the inner side of the reinforced concrete secondary lining layer; water in the drainage pipe is drained to the drainage ditch through the transverse water diversion pipe, and water in the drainage ditch is drained to the reservoir; a heating pipe network is wrapped in the polyurethane insulation board, the inlet end of the heating pipe network is connected with the heating system, and the outlet end of the heating pipe network is connected with the reservoir. Hot water is circularly conveyed to the in-tunnel heating pipe network through the out-tunnel heating system, heat is continuously provided for the heat preservation layer and gradually transmitted to other structures of the tunnel, and the problems that no heat source exists in the tunnel internal structure during operation, and the temperature of the tunnel internal structure is too low for a long time due to the fact that the shallow-buried section tunnel structure easily exchanges heat with surrounding rock are solved.

Description

Technical Field

[0001] This utility model relates to the field of construction technology for frost-resistant tunnel sections in cold regions, and in particular to a structure and heating system for shallow-buried frost-resistant railway tunnel sections in cold regions. Background Technology

[0002] In recent years, as my country's railway network planning has gradually expanded towards the western regions, railways will inevitably traverse high-altitude and cold regions. If effective anti-freezing technologies are not adopted for shallow-buried railway tunnels traversing these regions, repeated freeze-thaw cycles can lead to frost damage in the tunnel structure, such as frozen drainage systems, frost heave of surrounding rock, ice buildup in the arch, and cracking of the lining, thus affecting normal railway operations.

[0003] To address the aforementioned issues, the anti-frost damage technologies adopted in railway tunnels traversing high-altitude and cold regions in recent years mainly fall into three categories: 1. Installing a sufficiently thick insulation layer between the tunnel's primary support and secondary lining structures; 2. Heating and insulating the tunnel structure using an electric heat tracing system; 3. Installing cold-proof and insulated doors. However, all of these technologies have limitations. For example, insulation layers without a heat source can only delay heat loss; electric heat tracing systems are not only costly to operate and require frequent maintenance, but also suffer from problems such as resistor burnout and aging wires that are difficult to repair; and cold-proof and insulated doors, due to frequent opening and closing, have unsatisfactory insulation effects and interfere with normal railway operations.

[0004] Therefore, how to balance reducing the cost of anti-freezing measures and improving anti-freezing performance in the construction and operation of railway tunnels has become an urgent technical challenge to be solved in this field. Utility Model Content

[0005] The purpose of this utility model is to provide a structure and heating system for shallow-buried, frost-resistant railway tunnels in high-altitude and cold regions, which solves the technical problems of long-term low temperature inside the tunnel due to the lack of heat source in the tunnel's internal structure during operation and the easy heat exchange between the shallow-buried tunnel structure and the surrounding rock.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A shallow-buried, frost-resistant railway tunnel structure and heating system for high-altitude and cold regions includes an insulating mortar layer attached to the surrounding rock. On the other side of the insulating mortar layer, a concrete initial support layer, a drainage pipe, a non-woven geotextile, an EVA waterproof board, a polyurethane insulation board, and a reinforced concrete secondary lining layer are sequentially attached. A drainage ditch is provided on the inner side of the reinforced concrete secondary lining layer. Water in the drainage pipe is discharged to the drainage ditch through a transverse water inlet pipe, and water in the drainage ditch is discharged to a water storage tank.

[0008] The polyurethane insulation board is wrapped with a heating pipe network. The inlet end of the heating pipe network is connected to the heating system, and the outlet end is connected to the water storage tank.

[0009] In some embodiments, the drain pipe includes an HPDE circumferential perforated drain pipe and an HPDE longitudinal non-perforated drain pipe connected to both ends of the HPDE circumferential perforated drain pipe, wherein the outlet end of the HPDE longitudinal non-perforated drain pipe is connected to a transverse water inlet pipe.

[0010] In some embodiments, the heating pipe network includes multiple steel pipes arranged horizontally and vertically, which are connected by multi-port joints to ultimately form the pipe network.

[0011] In some embodiments, the steel pipe is tied to the EVA waterproof membrane with EVA waterproof membrane strips, and the two ends of the EVA waterproof membrane strips are fixed to the EVA waterproof membrane with hot melt washers.

[0012] In some embodiments, the steel pipe is suspended above the EVA waterproof membrane by EVA waterproof membrane strips, that is, the polyurethane insulation board completely covers the steel pipe, and a gap is left between the bottom of the steel pipe and the EVA waterproof membrane.

[0013] In some embodiments, the drainage ditch includes a left wall drainage ditch and a right wall drainage ditch disposed inside the reinforced concrete secondary lining, and a central drainage ditch is provided between the left wall drainage ditch and the right wall drainage ditch.

[0014] In some embodiments, to enhance the insulation effect, the steel pipe, the inner wall of the left wall drainage ditch, the inner wall of the right wall drainage ditch, the inner wall of the central drainage ditch, and the inner wall of the water storage tank are all wrapped with polyurethane insulation boards.

[0015] In some embodiments, the heating system includes a controller, a solar panel, and a hot water tank. The outlet of the hot water tank is connected to a heating network via a pipeline, and the inlet is connected to a water storage tank via a circulating water pump. A water level gauge probe is provided on the inner wall of the hot water tank, and an electric heater is provided inside. The controller is connected to the solar panel, the water level gauge probe, the circulating water pump, and the heater.

[0016] In some embodiments, a temperature control valve is provided on the pipeline connecting the hot water tank and the heating network, and the temperature control valve can control the flow of water from the hot water tank to the heating network according to the set temperature.

[0017] This invention employs a small amount of vitrified microsphere-mixed insulating mortar to reinforce the surrounding rock during tunnel excavation, improving the insulation of the reinforced area and reducing heat exchange between the shallow-buried tunnel structure and the surrounding rock. An external heating system circulates hot water through the internal heating network, continuously providing heat to the insulation layer and gradually transferring it to the rest of the tunnel structure. This fundamentally solves the problems of insufficient heat source within the tunnel structure during operation and the prolonged low temperature caused by easy heat exchange between the shallow-buried tunnel structure and the surrounding rock. Furthermore, it reduces the occurrence of frost damage such as frozen drainage pipes, frost heave of the surrounding rock, ice buildup in the arch, and cracking of the lining.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. Adding a small amount of vitrified microsphere thermal insulation mortar to the surrounding rock of the tunnel can increase the thermal insulation of the grouting reinforcement zone and reduce the heat loss of the initial support structure of shallow tunnels that are susceptible to freeze-thaw cycles.

[0020] 2. The tunnel's internal insulation measures consist of a heating pipe network made of steel pipes, polyurethane insulation boards, and a layer of vitrified microsphere insulation mortar. The heating pipe network provides a heat source for the tunnel interior, while the vitrified microsphere insulation mortar layer and polyurethane insulation boards form a double-layer insulation system for the tunnel structure.

[0021] 3. The tunnel drainage ditch flows into a concrete storage tank, and the water is then pumped into a hot water tank for heating and distribution to the heating network via a circulating water pump. This recycling of tunnel drainage is both environmentally friendly and solves the problem of water supply difficulties in high-altitude and cold regions. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 for Figure 1 Enlarged structural diagram at point A;

[0024] Figure 3 This is a cross-sectional structural diagram of the present invention;

[0025] Figure 4 This is a schematic diagram of the installation structure of the steel pipe of this utility model;

[0026] Figure 5 This is a schematic diagram of the connection structure between the heating pipe network and the heating system of this utility model;

[0027] Figure 6 This is a schematic diagram of the connection structure between the horizontal water inlet pipe and the drainage ditch of this utility model;

[0028] Figure 7 This is a schematic diagram showing the connection between the controller of this utility model and the solar panel, etc.

[0029] As shown in the figure:

[0030] 1. Thermal insulation mortar layer; 2. Concrete initial support layer; 3. Horizontal water inlet pipe; 4. Reinforced concrete secondary lining layer; 5. Polyurethane insulation board; 6. Steel pipe; 7. EVA waterproof board; 8. Non-woven geotextile; 9. HPDE circumferential perforated drainage pipe; 10. HPDE longitudinal non-perforated drainage pipe; 11. Left wall drainage ditch; 12. Central drainage ditch; 13. Right wall drainage ditch; 14. Hot water tank; 15. Water level gauge probe; 16. Controller; 17. Solar panel; 18. Thermostatic valve; 19. Water storage tank; 20. Multi-way connector; 21. Hot melt gasket; 22. Circulating water pump; 71. EVA waterproof board strip. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0032] Please see Figures 1-3 A shallow-buried, frost-resistant railway tunnel structure and heating system for high-altitude and cold regions includes an insulating mortar layer 1 attached to the surrounding rock. The insulating mortar layer 1 is a vitrified microsphere insulating mortar layer, with the vitrified microsphere content ranging from 10% to 20%. On the other side of the insulating mortar layer 1, a concrete primary support layer 2, a drainage pipe, a non-woven geotextile 8, an EVA waterproof board 7, a polyurethane insulation board 5, and a reinforced concrete secondary lining layer 4 are sequentially attached. A drainage ditch is provided on the inner side of the reinforced concrete secondary lining layer 4.

[0033] like Figure 6 As shown, the drainage pipe includes an HPDE circumferential perforated drainage pipe 9 and an HPDE longitudinal non-perforated drainage pipe 10 connected to both ends of the HPDE circumferential perforated drainage pipe 9. The outlet end of the HPDE longitudinal non-perforated drainage pipe 10 is connected to the drainage ditch through a transverse water inlet pipe 3. The transverse water inlet pipe 3 has a certain slope, that is, the height of the HPDE longitudinal non-perforated drainage pipe 10 is higher than the height of the drainage ditch. The water in the drainage ditch is discharged into the water storage tank 19.

[0034] The thermal insulation mortar layer 1 and polyurethane insulation board 5 serve as a double-layer thermal insulation system for the tunnel structure. The heating pipe network serves as a heating source inside the tunnel, continuously providing heat to the concrete primary support layer 2, the reinforced concrete secondary lining layer 4, the transverse water diversion pipe 3, the HPDE circumferential perforated drainage pipe 9, and the HPDE longitudinal non-perforated drainage pipe 10.

[0035] like Figure 4-5As shown, the heating pipe network includes multiple horizontally and vertically laid steel pipes 6. The steel pipes 6 are galvanized steel pipes with strong corrosion resistance. The horizontally and vertically laid steel pipes 6 are connected by multi-way joints 20 to form a pipe network. The multi-way joints 20 are tee or four-way joints.

[0036] The steel pipe 6 is tied to the EVA waterproof membrane 7 using EVA waterproof membrane strips 71 cut from the EVA waterproof membrane 7. Both ends of the EVA waterproof membrane strips 71 are fixed to the EVA waterproof membrane 7 by heat-melting washers 21 and ultrasonic welding. The steel pipe 6 is suspended above the EVA waterproof membrane 7, meaning that the polyurethane insulation board 5 completely encloses the steel pipe 6, leaving a certain gap between the bottom of the steel pipe 6 and the EVA waterproof membrane 7.

[0037] The thickness of the polyurethane insulation board 5 should be determined based on factors such as the average temperature of the coldest month in the local area, the temperature difference between the insulation layer and the secondary lining, and hydrological conditions, combined with construction methods and standards (determined according to tunnel construction requirements); to facilitate on-site installation and provide sufficient heat to the entire tunnel structure, the outer diameter of the galvanized steel pipe 6 is 90% to 95% of the designed thickness of the polyurethane insulation board 5.

[0038] To ensure that the heat transfer from the galvanized steel pipes 6 within the insulation layer is sufficient to prevent the surface of the reinforced concrete secondary lining 4 from being affected by frost heave, and to ensure that heat transfer within the polyurethane insulation board 5 is not lost, the spacing of the transverse steel pipes 6 should be less than the requirements calculated by the following formula:

[0039] Q1 = c·m·(T2-T1) (1);

[0040] m=ρ·S·l (2);

[0041] Q2=3.6·λdt(T3-T4) (3);

[0042]

[0043] Wherein: because heat is transferred without loss in the polyurethane insulation board 5, the heat Q1 and Q2 are equal, and the temperatures T3 and T2 are equal. c is the specific heat capacity of water, ρ is the density of water, S is the inner diameter area of ​​the steel pipe 6, l is the spacing between the transverse steel pipes 6, T1 is the initial water temperature of the hot water tank 14, and T2 is the water temperature in the steel pipe 6. λ is the thermal conductivity of the reinforced concrete lining layer 4, d is the thickness of the reinforced concrete lining layer 4, t is the time for heat to be transferred to the surface of the reinforced concrete lining layer 4, T3 is the interface temperature between the polyurethane insulation board 5 and the reinforced concrete lining layer 4, and T4 is the atmospheric temperature at which the tunnel structure suffers frost damage, generally taken as 0℃.

[0044] The drainage ditch includes a left wall drainage ditch 11 and a right wall drainage ditch 13 located inside the reinforced concrete secondary lining 4, with a central drainage ditch 12 located between the left wall drainage ditch 11 and the right wall drainage ditch 13. Water from the left wall drainage ditch 11, the right wall drainage ditch 13, and the central drainage ditch 12 all flows into the water storage tank 19.

[0045] To further improve the insulation effect, the steel pipe 6, the left wall drainage ditch 11, the right wall drainage ditch 13, the central drainage ditch 12, and the water storage tank 19 are all wrapped with polyurethane insulation boards 5.

[0046] like Figure 5 As shown, the heating system includes a controller 16, a solar panel 17, and a hot water tank 14. The outlet of the hot water tank 14 is connected to a heating network via a pipeline, on which a temperature control valve 18 is installed. The inlet is connected to a water storage tank 19 via a circulating water pump 22. A water level gauge probe 15 is installed on the inner wall of the hot water tank 14, and an electric heater is installed inside. The controller 16 is connected to the solar panel 17, the water level gauge probe 15, the circulating water pump 22, and the heater. The electric heater is an electric heating rod or an electric heating plate, located at the bottom of the hot water tank 14.

[0047] The water level probe 15 is a laser water level gauge used to monitor the water level in the hot water tank 14. When the water level in the hot water tank 14 is lower than 70% of the initial water level, the controller 16 turns on the circulating water pump 22 to pump water from the concrete storage tank 19 into the hot water tank 14. When the controller 16 detects that the ambient temperature is lower than 5°C, it starts to heat the water stored in the hot water tank 14, and the maximum water temperature does not exceed 40°C. When the temperature is monitored to be 25°C or higher, the temperature control valve 18 opens the water valve to deliver hot water from the hot water tank 14 to the steel pipe 6.

[0048] like Figure 7 As shown, the controller 16 is a DWYK intelligent water temperature and level controller. The controller 16 is connected to the water level gauge probe 15, the solar panel 17, the circulating water pump 22, and the heater. The solar panel 17 is equipped with a battery, which can provide power to the heating system during power outages.

[0049] The construction method of this utility model is as follows:

[0050] Step 1: Grout the surrounding rock of the excavated tunnel with vitrified microsphere insulating mortar. After the grouting strength reaches 100%, apply C25 wet sprayed concrete for initial spraying. After the flatness meets the standard, lay out and install the HPDE circumferential perforated drainage pipe 9, HPDE longitudinal non-perforated drainage pipe 10, and transverse water inlet pipe 3. During the installation process, the HPDE circumferential perforated drainage pipe 9 and HPDE longitudinal non-perforated drainage pipe 10 must be completely wrapped by the non-woven geotextile 8. After the wet sprayed concrete strength reaches 100%, position and install the non-woven geotextile 8 and EVA waterproof membrane 7.

[0051] Step 2: After the installation of the waterproofing and drainage structures in Step 1, including the non-woven geotextile 8, EVA waterproof membrane 7, HPDE circumferential perforated drainage pipe 9, HPDE longitudinal non-perforated drainage pipe 10, and transverse water inlet pipe 3, is completed, the hot-melt gasket 21 is firmly welded to the EVA waterproof membrane 7 using ultrasonic welding. The orientation of the steel pipe 6 is determined, and the overlap center deviation of the polyurethane insulation board 5 should be controlled within 2mm, connected via multi-way connectors 20. After the heating pipe network composed of the steel pipes 6 is stable, the remaining EVA waterproof membrane strips 71 from the cut EVA waterproof membrane 7 are used to bind and fix the steel pipes 6.

[0052] Step 3: After the heating pipe network composed of steel pipes 6 from Step 2 is installed and fixed, connect the second row of steel pipes 6 on the left to the water heater 14 outside the hole, and gradually install the water level gauge probe 15, controller 16, solar panel 17, thermostatic valve 18, and circulating water pump 22, and debug the above equipment. Simultaneously with the installation of the heating system, excavate a concrete storage tank 19 and lay polyurethane insulation boards 5 on the inner wall of the storage tank 19, with a burial depth greater than the local maximum freezing depth.

[0053] Step 4: Once the external heating system is operating normally, there is no water leakage in the heating pipe network, and the hot water from the heating pipe network eventually flows into the concrete water storage tank 19, position and install the polyurethane insulation board 5, completely wrap the steel pipe 6, and glue each polyurethane insulation board 5 with sealant.

[0054] Step 5: After the polyurethane insulation board 5 is installed in Step 4, fix and tie the reinforcing bars on the formwork of the reinforced concrete secondary lining 4 invert and pour concrete. When the concrete strength of the reinforced concrete secondary lining 4 invert reaches 85%, start pouring the tunnel invert filling layer. When the tunnel invert filling layer reaches 100%, fix and tie the reinforcing bars on the formwork of the concrete secondary lining 4 and pour concrete. When the concrete strength reaches 100%, start pouring the drainage ditch 11 on the left wall, the drainage ditch 12 in the center, and the drainage ditch 13 on the right wall of the tunnel, and lay polyurethane insulation board 5 on the inside of the drainage ditch.

[0055] The principle of this utility model is as follows:

[0056] 1. Adding a small amount of vitrified microsphere thermal insulation mortar to the surrounding rock of the tunnel can increase the thermal insulation of the grouting reinforcement zone and reduce the heat loss of the initial support structure of shallow tunnels that are susceptible to freeze-thaw cycles.

[0057] 2. Hot water circulates in the heating pipe network formed by steel pipes 6, and its heat is transferred to polyurethane insulation board 5 and gradually transferred to the internal structure of the tunnel and the vitrified microsphere insulation mortar layer 1, further reducing heat loss of the internal structure of the tunnel and heat exchange with the surrounding rock.

[0058] 3. Solar energy is converted into electrical energy by solar panels 17 configured with batteries, and excess electrical energy is stored in the batteries.

[0059] 4. Based on the monitored atmospheric temperature and the water level in the hot water tank 14, the controller 16 uses the circulating water pump 22 to pump the stored water in the concrete water storage tank 19 into the hot water tank 14 for heating.

[0060] 5. The temperature control valve 18 monitors the temperature of the hot water tank 14. Once the temperature reaches the target, it opens the water valve to deliver hot water to the steel pipe 6.

[0061] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A structure and heating system for shallow-buried, frost-resistant railway tunnel sections in high-altitude and cold regions, characterized in that, The structure includes a thermal insulation mortar layer (1) attached to the surrounding rock. On the other side of the thermal insulation mortar layer (1), a concrete primary support layer (2), a drainage pipe, a non-woven geotextile (8), an EVA waterproof board (7), a polyurethane insulation board (5), and a reinforced concrete secondary lining layer (4) are attached in sequence. A drainage ditch is provided on the inner side of the reinforced concrete secondary lining layer (4). Water in the drainage pipe is discharged to the drainage ditch through a transverse water inlet pipe (3), and water in the drainage ditch is discharged to a water storage tank (18). The polyurethane insulation board (5) is wrapped with a heating pipe network. The inlet end of the heating pipe network is connected to the heating system, and the outlet end is connected to the water storage tank (19).

2. The structure and heating system for a shallow-buried, frost-resistant railway tunnel in a cold region according to claim 1, characterized in that, The drain pipe includes an HPDE circumferential perforated drain pipe (9) and an HPDE longitudinal non-perforated drain pipe (10) connected to both ends of the HPDE circumferential perforated drain pipe (9). The outlet end of the HPDE longitudinal non-perforated drain pipe (10) is connected to a transverse water inlet pipe (3).

3. The structure and heating system for shallow-buried, frost-resistant railway tunnels in high-altitude and cold regions according to claim 1, characterized in that, The heating pipe network includes multiple horizontally and vertically arranged steel pipes (6), which are connected by multi-port joints (20).

4. The structure and heating system for a shallow-buried, frost-resistant railway tunnel in a cold region according to claim 3, characterized in that, The steel pipe (6) is tied to the EVA waterproof membrane (7) by the EVA waterproof membrane strip (71), and the two ends of the EVA waterproof membrane strip (71) are fixed to the EVA waterproof membrane (7) by the hot melt washer (21).

5. A railway tunnel structure and heating system for shallow buried frost-resistant sections in high-altitude and cold regions according to any one of claims 3-4, characterized in that, The steel pipe (6) is suspended above the EVA waterproof membrane (7) via the EVA waterproof membrane strip (71).

6. The structure and heating system for a shallow-buried, frost-resistant railway tunnel in a cold region according to claim 3, characterized in that, The drainage ditch includes a left wall drainage ditch (11) and a right wall drainage ditch (13) located inside the reinforced concrete secondary lining (4), and a central drainage ditch (12) is provided between the left wall drainage ditch (11) and the right wall drainage ditch (13).

7. The structure and heating system for a shallow-buried, frost-resistant railway tunnel in a cold region according to claim 6, characterized in that, The steel pipe (6), the left wall drainage ditch (11), the right wall drainage ditch (13), the central drainage ditch (12), and the water storage tank (19) are all wrapped with polyurethane insulation board (5).

8. The structure and heating system for a shallow-buried, frost-resistant railway tunnel in a cold region according to claim 1, characterized in that, The heating system includes a controller (16), a solar panel (17), and a hot water tank (14). The outlet of the hot water tank (14) is connected to the heating network through a pipeline, and the inlet is connected to the water storage tank (19) through a circulating water pump (22). The inner wall of the hot water tank (14) is equipped with a water level probe (15), and an electric heater is installed inside. The controller (16) is connected to the solar panel (17), the water level probe (15), the circulating water pump (22), and the heater.

9. The structure and heating system for a shallow-buried, frost-resistant railway tunnel in a cold region according to claim 8, characterized in that, A temperature control valve (18) is provided on the pipeline connecting the hot water tank (14) and the heating network.

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