A fire water supply system for super long tunnels
By setting up high-level pools and transportation channels in high-altitude ultra-long highway tunnels at high cold and high altitude, the constant high-pressure water supply of gravity flow is achieved by using water seepage in the tunnel, freezing and overpressure problems are solved, construction and maintenance costs are reduced, and the safety of the water supply system is improved. Sexual and economical.
Patent Information
- Application Number
- CN201910945124.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-09-30
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2039-09-30
AI Technical Summary
In high-altitude ultra-long road tunnels at high altitudes, existing fire water supply systems are difficult to solve problems such as freezing of fire water sources, excessive heading of submersible pressurized pumps, insufficient pressure on water pipelines, and difficulty in preventing freezing and insulation, resulting in water supply safety and construction difficulties, resulting in water supply safety and difficulty in construction High, high maintenance costs.
Design an ultra-long tunnel fire water supply system. By setting up multiple high-level water pools and transportation channels in the tunnel, using structural seepage in the tunnel as the water source, using gravity flow constant high pressure water supply, and district water supply to reduce static height difference, transportation channels It is convenient for water transport trucks and maintenance, and avoids the construction of high-level water pools and pump rooms outside the tunnel.
It realizes stable and reliable fire water supply in high-altitude environments, reduces construction and maintenance costs, avoids the risk of overpressure and freezing of pipeline networks, and improves the safety and economics of the water supply system.
Smart Images
Figure CN110735463B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of fire fighting systems in super-long highway tunnels, and more specifically relates to a fire fighting water supply system for super-long tunnels, which is suitable for water supply of fire fighting systems in super-long highway tunnels. Background Art
[0002] As a basic component of highway routes, highway tunnels develop in parallel with highway construction. As the focus of the country's infrastructure construction in recent years, the high altitude and cold weather in the western region have become a major difficulty in design and construction. The design of the fire water supply system in highway tunnels is divided into the water supply system outside the tunnel and the pipe network system inside the tunnel. The water supply system outside the tunnel is usually divided into the following: Figure 1 Set up a constant high-pressure water supply system for high-level fire water tanks, such as Figure 2 A stable high-pressure fire water supply system is set up with a low-level fire water tank-air pressure water supply equipment.
[0003] The constant high-pressure water supply system of the high-level fire water tank outside the tunnel usually includes a water source 1, a low-level water tank 2, a water pump room 3, a water storage pipeline connected to the high-level water tank 4 in sequence, and a water supply network 6 connected to the high-level water tank 4 through a water supply pipeline 5. The schematic diagram of the principle is shown in the figure. Figure 1 , wherein the water source 1 is usually one or a combination of municipal tap water, deep well water, mountain stream, river water, surrounding rock infiltration water or spring water. The low-level water reservoir 2 and the pump house 3 are usually set near the tunnel entrance, and the high-level water reservoir 4 is set on the mountain at one end of the tunnel where the low-level water reservoir 2 is located. The elevation of the bottom of the low-level water reservoir 2 must meet the design elevation, and the water supply network 6 is located in the tunnel. The advantages of this water supply system are: there is a natural height difference between the high-level water reservoir 4 outside the tunnel and the water supply network 6 inside the tunnel that meets the design requirements, the system forms a constant gravity flow water supply, and once the fire hydrant is opened, there is a fire-fighting water consumption that can meet the design pressure and flow, and the water supply is safe, stable and reliable. Its disadvantages are: the high-level water tank 4 is usually located on a mountain above 50m near the tunnel entrance, and it is also necessary to set up and down the mountain water supply pipelines 5, maintenance access roads and other facilities, which require additional land acquisition, and there may be risks such as damage to vegetation and landslides.
[0004] The stable high-pressure water supply system outside the tunnel usually includes a water source 1, a low-level water reservoir 2, a pump room 3, and a water supply network 6, which are connected in sequence. The schematic diagram is as follows: Figure 2, wherein the water source 1 is usually one or a combination of municipal tap water, deep well water, mountain stream, river water, surrounding rock seepage water or spring water. The low-level water reservoir 2 and the water pump room 3 are usually set near the tunnel entrance. The water pump room 3 is equipped with air pressure water supply equipment, which directly supplies water to the water supply network 6 in the tunnel after absorbing water from the low-level water reservoir 2 and pressurizing it. The advantage of this water supply system is that compared with the constant high-pressure water supply system, the system only needs to set up a low-level water reservoir 2 and a set of air pressure water supply equipment at the tunnel entrance, and does not need to set up high-level water tanks 4, maintenance access roads, uphill and downhill water supply pipelines 5 and other facilities, which reduces the cost of laying pipelines, occupies less space, and has less damage to the environment. Its disadvantages are: the system usually uses pneumatic water supply equipment to stabilize the pressure of the water supply network 6. In the event of a fire, the main fire pump must be turned on to provide fire water that meets the design flow and pressure requirements. The pneumatic water supply equipment needs to be turned on all year round. Once the main pump fails or the power is cut off during a fire, it will not be able to provide fire water that meets the design flow and pressure requirements. The water supply safety and reliability is low, the subsequent operation and maintenance management workload is large, and the electricity bill is high.
[0005] For conventional highway tunnels, the tunnel fire water supply should preferably adopt a constant high-pressure water supply system with a high-level water tank 4 set outside the tunnel. When there is no condition to set up a high-level water tank 4, a stable high-pressure water supply system can be used.
[0006] For highway tunnels in cold and high altitude areas, the fire-fighting equipment and facilities outside the tunnel are usually set below the freezing line to achieve the purpose of anti-freezing and heat preservation. However, since the high-level water pool is usually at a high elevation and the freezing line is deep, construction is difficult. Data show that the permafrost layer on the northern slope of Kunlun Mountain on the Qinghai-Tibet Highway and the Anduo area in northern Tibet is 80 to 100 meters thick, and the permafrost depth in the hinterland of Tianshan Mountain has reached more than 4 meters. Therefore, this type of tunnel generally uses a stable high-pressure water supply system to supply water to the fire-fighting pipeline network in the tunnel.
[0007] With the rapid advancement of infrastructure construction in the western part of the country, more and more high-altitude and cold highway tunnels are emerging. In terms of route selection, in order to significantly shorten the length of the entire line, some projects will have many extra-long tunnels of more than 5 km, or even super-long tunnels of more than 10 km. The typical characteristics of such super-long tunnels are long tunnels and large static height differences in tunnels. For the design of tunnel fire protection systems, there are still difficult problems in the anti-freezing and insulation of fire protection equipment and facilities. The following takes Xinjiang Wuwei Expressway as an example to illustrate the key difficulties in the design of such tunnel fire protection systems.
[0008] The starting point of Xinjiang Wuwei Expressway Project is located on the west side of the G30 Cangfanggou Interchange in Urumqi City, connecting with the planned West Ring Expressway Xishan South Interchange, and partially using the built G216 Class A Highway as the main line of this project. The route generally goes from north to south along the Daxigou Shuo River, passing Yongfeng Township, Qianxia and Houxia along the way, and sets up a special tunnel at Wangfeng Road Station to cross Shengli Daban, enter the jurisdiction of Hejing County, along Wusuogou to Wulasutai, and then go downstream along the "Wulasutai River" and "Habuqiha River", passing Shengli Bridge, Barentai, Jinte Steel Plant to Huangshuigou Hydrological Station, and then enter the Gobi Plain area, passing the west of the 21st Regiment and the east of Qigexing Town, crossing the Heku Expressway to Tashdian at Ziniquan, passing through Kuruktag Mountain, crossing the Tuku Railway, and arranging along the east side of the Korla Planning Area, ending at Qiongkule Village on the east side of Yuli County.
[0009] The Tianshan Super-Long Tunnel, with a single-hole length of about 21 km, is a major control project of this expressway. It is located at an altitude of more than 3,000 meters. The maximum static height difference in the tunnel reaches 235m and the slope is 0.64 ̊. The design of its water fire-fighting system is the key to the design of the tunnel's ancillary projects.
[0010] The main features of the tunnels along the route of this project are: 1) There are many tunnels, with a total of 20 tunnels along the route; 2) Each tunnel is relatively long, among which the Tianshan Tunnel is about 21km long; 3) The slope is gentle, with a slope of 0.64 ̊; 4) The altitude is high and cold, reaching more than 3,000 meters. The historical average temperature on the northern slope of Tianshan is 2~3℃, and the average temperature in winter is -10~-12℃; 5) The permafrost line is deep, and the construction is difficult. The average permafrost depth is about 3 meters, and the local permafrost depth reaches 17 meters; 6) The tunnel-bridge ratio is high, and the cave entrance space is limited.
[0011] According to the characteristics of the project, the initial difficulties in designing the fire protection system of conventional tunnels along the project are: 1) The choice of water supply system outside the tunnel, whether to set up a constant high pressure system or a stable high pressure system. 2) There are many tunnels in this project, and the bridge-tunnel ratio is high. Most tunnel openings do not have the conditions for building pump rooms and fire water pools. 3) The freezing season is long and the frozen soil is deep in the project site. It is difficult to solve the antifreeze and insulation problems of fire water pools, pump rooms, fire pipes and other equipment and facilities outside the tunnel. 4) The water source for tunnel fire protection is surface water or groundwater.
[0012] For the Tianshan Tunnel with a single hole length of about 21 km, in addition to the above difficulties, the fire protection system design also has the following preliminary design difficulties:
[0013] 1. There is no suitable fire water source outside the tunnel
[0014] The fire-fighting water source for conventional project tunnels is usually one or a combination of municipal tap water, surface water (mountain streams, river water, surrounding rock seepage water or spring water), and groundwater (deep well water).
[0015] For the Tianshan super-long tunnel, there is no municipal tap water near the tunnel. If surface water (mountain streams, river water or spring water) outside the tunnel is used, the surface water will freeze in winter, the water pipeline will be buried too deep, and it will be difficult to lay. If groundwater is used, there will be problems such as the need to explore the burial depth of the groundwater source, the water pipeline will be buried too deep, and it will be difficult to lay. In addition, the biggest difficulty in setting up a fire water source outside the tunnel is that both the surface water source and the groundwater source must be equipped with a submersible booster pump to transport water to the tunnel. The maximum static height difference in the Tianshan Tunnel reaches 235m, resulting in the maximum head of the submersible booster pump to reach more than 300 meters, and the water pipeline cannot withstand such a large pressure.
[0016] 2. Conventional fire water supply system is difficult to implement in this project
[0017] 1) Constant high-pressure water supply system outside the tunnel
[0018] According to the "Highway Tunnel Design Code, Part 2, Traffic Engineering and Ancillary Facilities" (JT D70 / 2-2014), the tunnel fire water supply should adopt a constant high-pressure water supply system with high-level fire water tanks; when there is no condition to set up a high-level water tank, a stable high-pressure water supply system can be used. Conventional tunnel fire water supply systems in highway tunnels are usually constant high-pressure and stable high-pressure water supply systems outside the tunnel. This tunnel is located in a high-altitude cold area. If a constant high-pressure water supply system outside the tunnel is used, the fire pipe network in the tunnel can be divided into two areas with a total of two ring networks at most. The high-level water tanks at both ends of the tunnel supply fire water to one area respectively, but the maximum static height difference in the tunnel is as high as 235m (the longitudinal surface is a herringbone slope). According to hydraulic calculations, the high-level water tank at the small pile end of the tunnel is reverse uphill for the pipe network in the tunnel. The pool bottom elevation must overcome a height difference of 150 meters and a head loss of 10 kilometers plus a water supply pressure of 40 meters at the most unfavorable point. The height difference between the bottom of the high-level water tank and the tunnel entrance is as high as about 250 meters, so it is impossible to set up this high-level water tank. The high-level water tank at the large pile end of the tunnel must overcome the height difference of 23m and the head loss of 5 kilometers plus the water supply pressure of 40 meters at the most unfavorable point. It should be set on a mountain with a height difference of at least 100 meters from the tunnel entrance. According to the main data, the extreme minimum temperature in the tunnel site area is -43.4℃, the average permafrost depth is about 3 meters, and the local permafrost depth reaches 17 meters. The conventional method of burying the high-level water tank below the permafrost line to achieve anti-freeze and heat preservation is difficult to implement, and the high-level water tank is usually located on the mountain. Due to steep terrain, covering soil and ice, the construction is very difficult. Similarly, the anti-freeze problem of the upper and lower water supply pipes is also difficult to solve. Even if a small section of the pipeline system is frozen, the entire pipeline will not be able to pass water, and the water supply reliability is very low. Taking all the above factors into consideration, the constant high-pressure water supply plan outside the tunnel is not feasible.
[0019] 2) Tunnel external stable high-pressure water supply system
[0020] The stable high-pressure water supply system outside the tunnel is a water supply scheme that uses air pressure water supply equipment installed near the tunnel entrance to draw water from a low-level water tank and directly pressurize it to supply water for tunnel fire fighting. For general highway tunnels, the tunnel pipeline network of the stable high-pressure water supply system is usually a large ring network, the water supply system is a zone, and the water supply pump group directly draws water and pressurizes it to supply the ring network. Tianshan Tunnel is a single-slope tunnel with a length of about 21km. The height difference of the road surface at both ends of the tunnel is about 235m. If only a large ring network is set up in the tunnel, the water supply main pipe in the tunnel is DN200 and the water supply pressure at the most unfavorable point in the tunnel is 0.4MPa. The static water pressure at the farthest point of the tunnel reaches 2.35MPa, and the dynamic pressure of the water supply reaches 1.9MPa, which exceeds the nominal pressure of 1.6MPa of the conventional fire main pipe (steel pipe). If a pipe with a higher nominal pressure (for example, 2.5MPa) is used, it is easy to cause pipeline leakage or even pipe burst and other accidents. In addition, the water outlet pressure of the fire hydrant is too high, which makes it difficult to control the operation during fire extinguishing, and may even accidentally injure firefighters, endangering the operational safety of the tunnel.
[0021] In summary, for the Tianshan super-long tunnel with a length of about 21 km, it is located at an altitude of more than 3,000 meters, with perennial frozen soil, an average frozen soil depth of about 3 meters, and a local frozen soil depth of 17 meters. The slope is gentle. If the tunnel is designed according to the conventional design to directly set up a constant high-pressure or stable high-pressure water supply system with high and low-level water tanks, pump rooms, and pipe networks outside the tunnel, there will be major problems with the fire water source: surface water will freeze, the depth of groundwater needs to be explored, and the head of the submersible booster pump is too high and the water delivery distance is too long; second, the anti-freezing problem of high and low-level water tanks, pump rooms, and pipes outside the tunnel is difficult to solve; third, if high and low-level water tanks are set outside the tunnel, the pipe network in the tunnel will be divided into two areas, the bottom elevation of the high-level water tank will be very high, and the static pressure and dynamic pressure of the pipe network in the tunnel will be too large, which is easy to cause pipeline leakage or even pipe bursts and other accidents, endangering the operational safety of the tunnel. The fire water supply system solution for conventional highway tunnels cannot be implemented in super-long tunnels such as the Tianshan Tunnel, which are located in high-altitude and cold areas. Summary of the invention
[0022] The technical problem to be solved by the present invention is to provide a fire water supply system for an ultra-long tunnel with a length of more than 9.89 km, a height difference of more than 198.89 m, an ambient temperature below 0°C for a long time, and a frozen soil layer depth of more than 3 meters. The system has a simple structure and is easy to use. It can solve the problem of fire water pools freezing due to low ambient temperature, the problem of fire water pools being difficult to dig and construct due to thick frozen soil in high-altitude areas, the problem of too large height difference in the tunnel, and the problem of static overpressure in the fire pipe network. At the same time, it can provide a fire water supply system with the lowest construction and maintenance costs.
[0023] In order to achieve the above-mentioned purpose, the present invention adopts the following technical measures:
[0024] A fire water supply system for an ultra-long tunnel, comprising a tunnel and a service tunnel, wherein the tunnel is parallel to the service tunnel, the height difference of the road surface at both ends of the tunnel is greater than 198.89m, the longitudinal slope is not greater than 2%, the longitudinal slope length is greater than 9.89km, the temperature in the mountainous area outside the tunnel is lower than 0°C all year round, and the thickness of frozen soil in the mountainous area is greater than 3 meters, wherein the tunnel has a lining constructed of permeable materials and a road surface paved with waterproof materials, the service tunnel has a lower pipe gallery road surface lower than the tunnel road surface and a drainage ditch lower than the lower pipe gallery road surface, and a side wall of the tunnel is connected to the service tunnel through a downward inclined transport channel The tunnel and service tunnel are divided into several tunnel sections according to the ventilation shaft. A water storage tank is set at the low point of the drainage ditch in each tunnel section. The service tunnel in each tunnel section is connected to the high-level water tank cavern through a transportation channel. The height difference between the ground of each high-level water tank cavern and the high point of the tunnel ground in each tunnel section is H, H=30~100m. A high-level water tank is arranged in each high-level water tank cavern. A water supply pipe connecting the high-level water tank and the submersible booster pump arranged in the water storage tank is laid in the transportation channel. Each high-level water tank is connected to the water supply network arranged in the corresponding tunnel section through a water supply pipe to provide fire-fighting water.
[0025] Furthermore, a water intake and a water supply port are arranged at each water reservoir in each tunnel section to facilitate water tankers to take water from the water reservoir and supply water to the water reservoir.
[0026] Furthermore, the slope of the transport channel is no more than 30%, which facilitates the water tanker to transport water to the high-level water tank through the transport channel.
[0027] Furthermore, the longitudinal slope of the starting tunnel section located at the starting tunnel entrance in the tunnel section is smaller than the longitudinal slope of the remaining tunnel sections, wherein the longitudinal slope = tan(ϴ) × 100%, ϴ is the longitudinal slope inclination angle, the starting tunnel section and the two sections of water supply pipes in the adjacent tunnel section share a high-level water tank corresponding to the adjacent tunnel section, and the height difference between the floor of the high-level water tank cavern where the high-level water tank is located and the high point of the tunnel floor in the starting tunnel section is H' = H + sin(ϴ) × L, L is the length of the starting tunnel section.
[0028] The present invention takes the Tianshan Tunnel of Xinjiang Wuwei Expressway as an example, and its technical concept is: 3 ventilation shafts are set in the tunnel, and the fire water supply system is also divided into 4 zones with reference to the ventilation system using ventilation shafts for zoning (4 sections), and the zone pile number range is the same as the ventilation system (the ventilation zoning is relatively uniform). The idea is to dig a transportation channel (also used as a pipeline laying site, maintenance access road, air supply and exhaust channel, etc.) from the service tunnel to the cavern where the high-level water tank is located. The height difference between the 1# high-level water tank (that is, the high-level water tank set next to the 1# ventilation shaft, and the other high-level water tanks are similar) and the ground in the tunnel is about 46 meters, the height difference between the 2# high-level water tank and the ground in the tunnel is about 46 meters, and the height difference between the 3# high-level water tank and the ground in the tunnel is about 64 meters (sections 3 and 4 share the high-level water tank). The three high-level fire water tanks supply fire-fighting water for the four sections in the tunnel. It is a gravity flow constant high-pressure water supply. The water source is taken from the structural seepage in the tunnel, that is, the structural seepage collected by the drainage ditch in the lower pipe gallery of the tunnel horizontal pilot tunnel, and a reservoir is set at an appropriate position in the lower pipe gallery. A submersible pressure pump is set in the reservoir to pump water to the high-level water tank. In order to ensure the reliability of the water supply system, the design proposes to set up water intakes and water supply ports at each low-level water tank, so that in extreme water shortage situations, water tanks can be filled with water by water trucks or water can be taken from the water tanks. The overflow and discharge of the water tanks are all discharged from the drainage ditch at the lower level of the guide tunnel, and the overflow and discharge of the high-level water tanks are discharged from the drainage ditch of the transportation channel. The transportation channel and the high-level water tank cavern are equipped with supporting ventilation, lighting and drainage systems.
[0029] The cross-sectional width of the transport channel is 4.7m; the clearance height is 6.2m;
[0030] The slope of the transport channel is no more than 30%;
[0031] The area of the cavern is: 20m (length) x 12.5m (width);
[0032] The cross-sectional width of the cavern is: 12.5m; the clearance height is 9.25m;
[0033] The size of the high-level water pool and the drainage ditch of the transport channel is 15cm×15cm.
[0034] The high-level water tanks are all equipped with water inlet pipes, water outlet pipes, vent pipes, overflow pipes, and vent pipes. The inspection holes, iron ladders, wall pipes, wall pipe reinforcements, water pipe hangers, and vent holes attached to the high and low-level water tanks can all be found in "Rectangular Reinforced Concrete Water Tanks" (05S804). Grilles are installed at the inlet and outlet of the low-level water tank to prevent floating objects from blocking the pipes. The elevation of the bottom of the high-level water tank can make the pressure at the most unfavorable point of the tunnel water supply network not less than 0.4MPa. The water in the water tank is pumped to the high-level water tank, and then the high-level water tank supplies water to the tunnel ring water supply network through two outlet pipes. The network is always kept in a water state and can be put into use in the event of a fire.
[0035] A lightning-proof stainless steel fire water tank level sensor is installed in the high-level water tank for super-high and super-low water level alarms. The alarm signal is transmitted to the control cabinet, and then the control cabinet controls the start and stop of the water pump. When the water level drops to the minimum water level threshold, the submersible booster pump is started to replenish water. When the water level rises to the maximum water level threshold, the submersible booster pump is stopped to replenish water. The submersible booster pump control cabinet is installed in the submersible booster pump well room. The submersible booster pump is soft-start controlled and has a low-frequency automatic cycle inspection function; the submersible booster pump control cabinet communicates with the water pump room PLC through optical fiber and is controlled by the PLC; the control cable of the high-level water tank water level sensor is arranged with the DN100 water pipeline.
[0036] A remote pressure gauge is installed on the outlet pipe of the submersible booster pump to monitor whether the water supply pressure is normal when the pump is working. A liquid level sensor is installed in the deep well to monitor the real-time water level changes. All collected data is sent to the pump control cabinet.
[0037] The air supply and exhaust system is an axial flow fan + air duct system arranged in the transport channel and the high-level water pool cavern.
[0038] The lighting system is an LED lighting system and an emergency lighting system arranged in the transport channel and the high-level water pool cave.
[0039] The drainage system is to set drainage ditches in the high-level water tank cavern and the transportation channel to guide the structural seepage water to the drainage ditch of the service tunnel. At the same time, the overflow water and drain water of the high-level water tank are guided to the drainage ditch of the service tunnel.
[0040] The present invention is characterized in that the maximum height difference in the tunnel is about 235m, a "high-level water tank in the tunnel" is set at a suitable position in the tunnel, and the tunnel fire-fighting pipe network is reasonably divided into zones, each high-level water tank supplies water for tunnel fire-fighting in the corresponding zone, and the water supply system of the super-long tunnel is divided into several "short tunnels", which solves the problem of pipe network overpressure caused by excessive static height difference in the tunnel. In addition, the ambient temperature in the tunnel is higher than that outside the tunnel, and there is almost no problem of freezing of water supply pipes in the tunnel at a certain length from the tunnel entrance. The structural seepage in the tunnel can also be fully utilized to provide water source for fire-fighting pipes. More importantly, the "high-level water tank in the tunnel" is installed in the high-level water tank cavern, and the high-level water tank cavern is connected with the tunnel through a transportation channel. When the water supply to the high-level water tank fails, water can be supplied to the high-level water tank through the transportation channel by a water transport vehicle, and maintenance personnel can also enter the high-level water tank cavern from the transportation channel for maintenance and inspection, which is convenient for emergency and fault maintenance. At the same time, the construction cost of excavating the transportation channel and laying the water supply pipe connected to the high-level water tank is the lowest, and the maintenance cost is the lowest.
[0041] Compared with the prior art, this invention is the first in the industry for fire protection design of highway tunnels, and its main advantages are:
[0042] (1) Water supply safety and reliability: The Tianshan Tunnel adopts gravity flow constant high-pressure water supply throughout the line. The pipe network maintains water all year round, the water pressure is stable, water comes out as soon as the fire hydrant is opened, no pressurization and personnel supervision are required, the water supply system is safe and reliable, and the workload of later maintenance and management is small. In addition, the fire-fighting pipe network in the tunnel is divided into zones for water supply. Each pipe network is relatively independent, and the static height difference of 235m along the entire line is apportioned to three ring networks. The static height difference of each ring network is about 65m, which greatly reduces the risk of overpressure water supply in the pipe network. The water source is taken from the structural seepage in the tunnel. The structural seepage is relatively stable and reliable, and can meet the water requirements for fire fighting.
[0043] (2) Antifreeze and heat preservation: The high and low-level water tanks, water sources and submersible pressure pumps of the Tianshan Tunnel are all located inside the tunnel. The temperature inside the tunnel is higher than that outside the tunnel. There is no risk of freezing of fire-fighting equipment and facilities, and no additional antifreeze and heat preservation measures are required.
[0044] (3) Construction difficulty: The high and low-level water tanks and transportation channels are all constructed inside the tunnel, and are implemented simultaneously with the main civil engineering of the tunnel. The civil engineering construction unit comprehensively considers the construction methods and processes to avoid the risks of avalanches, landslides, damage to the environment, etc. caused by secondary excavation of the mountain outside the tunnel, which greatly reduces the construction difficulty.
[0045] (4) Economic efficiency: The fire pump room and the external insulation materials of the tunnel are eliminated. The civil construction of the water pool only requires a one-time investment. Each zone only needs to build one transportation channel and one high and low-level water pool, which greatly reduces the project investment and is easy to maintain in the later stage, with incomparable economic efficiency.
[0046] (5) Environmental protection: This project is located in the secondary water source protection area and glacier protection area. Building a pool at the tunnel entrance will not only damage the glacier and cause an imbalance in the local ecological environment, but the waste generated by building the pool will also easily cause water pollution. Therefore, the present invention is of great significance to promoting the construction of ultra-long highway tunnels in high-cold and high-altitude areas in my country, solving the design problems of ancillary projects, improving the reliability of tunnel disaster prevention and rescue, and promoting the comprehensive development of my country's modern transportation industry. BRIEF DESCRIPTION OF THE DRAWINGS
[0047] Figure 1 This is a schematic diagram of a constant high pressure water supply system;
[0048] Figure 2 Schematic diagram of the stable high pressure water supply system;
[0049] Figure 3 It is a longitudinal section schematic diagram of a fire water supply system for an ultra-long tunnel;
[0050] Figure 4 This is a clear cross-sectional view of a high-level water tank transportation channel of an ultra-long tunnel fire water supply system;
[0051] Figure 5 This is a clear cross-sectional view of the lining of a high-level water tank cavern in a super-long tunnel fire water supply system;
[0052] Figure 6 It is a cross-section diagram of a super-long tunnel transport tunnel, service tunnel and cross tunnel;
[0053] Figure 7 This is a general perspective view of an ultra-long tunnel fire water supply system.
[0054] The meanings of the numbers and symbols are as follows:
[0055] 1—water source, 2—low-level water reservoir, 3—water pump house, 4—high-level water reservoir, 5—downhill water supply pipeline, 6—water supply network, 7—water supply pipeline, 9—transportation channel, 10—water supply pipeline, 11—high-level water reservoir cavern, 12—drainage ditch, 14—left tunnel, 16—right line tunnel, 17—service tunnel, 18—lower-level pipeline gallery, 20—drainage ditch, 28—water intake, 29—water supply outlet, 27—water reservoir, L1#—1# section length 5395m, height difference 86m, horizontal length 5.5km, L2#—2# section length 5950m, height difference 97m, horizontal length 5.5km, L3#—3# section length 6000m, height difference 53m, horizontal length 5km, L4#—4# section length 3555m, height difference 23m, horizontal length 5km. DETAILED DESCRIPTION
[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0057] The present invention takes the Tianshan Tunnel of Xinjiang Wuwei Expressway as an example to illustrate the specific implementation manner of the present invention.
[0058] The three water supply schemes before the content of the present invention is determined are compared as follows. Compared with other mandatory schemes, the technical scheme of the present invention has significant advantages in construction cost and maintenance cost, which is not obvious:
[0059] Example 1: Using a high-level water pool next to the ventilation shaft (optimal solution)
[0060] like Figure 6 As shown, the total length of the left tunnel 14 and the right tunnel 16 are both 21km, the height difference between the two ends of the two tunnels is 235m, the slope is 0.26°~0.64°, the height difference per meter along the longitudinal direction of the two tunnels is 11mm / m, the average altitude of the two tunnels is 3000m, and the ambient temperature outside the tunnel is below 0℃ for a long time. The thickness of the frozen soil layer outside the tunnel exceeds 3~17m. It is parallel to the extension direction of the left tunnel 14 and the right tunnel 16. A service tunnel 17 is excavated between the two tunnels. The lower corridor pavement of the service tunnel 17 is lower than the pavement 19 of the left tunnel 14 and the right tunnel 16. The pavements of the left tunnel 14 and the right tunnel 16 are close to the service tunnel 17, and are connected to the service tunnel 17 through a downward inclined transportation channel 18. A drainage ditch 20 is provided in the middle of the lower corridor pavement of the service tunnel 17. The pavements of the left tunnel 14, the right tunnel 16 and the service tunnel 17 are paved with waterproof materials. The lining 13 structure of the left tunnel 14, the right tunnel 16 and the service tunnel 17 above the pavement is a permeable material. The drainage ditch 20 is used to collect structural seepage at the top of the left tunnel 14, the right tunnel 16 and the service tunnel 17.
[0061] like Figure 7 and Figure 3Three ventilation shafts 35 are arranged beside the left tunnel 14 and the right tunnel 16. Referring to the way that the ventilation system is divided into four zones (four tunnel sections) using the ventilation shafts 21, the left tunnel 14 and the right tunnel 16 are also divided into four zones, and the tunnel section pile number range is the same as the ventilation system (the ventilation zones are relatively uniform). In each tunnel section, a transport channel 9 is excavated from the service tunnel 17 to the high-level water tank cavern 11, which is also used for pipeline laying site, maintenance access road, air supply and exhaust channels, etc. The 4-1# high-level water tank is the high-level water tank 4 arranged in the high-level water tank cavern 11 next to the 35-1# ventilation shaft 35. A 400T water reservoir 27 is arranged in the lower corridor 18 of the service tunnel 17 near the transport channel 9. A submersible pressure pump is arranged in the water reservoir 27 to pump water along the water supply pipe 10 in the transport channel 9 to the high-level water tank 4. A ring water supply network 6 is laid in the left tunnel 14, the right tunnel 16 and the transport channel 9. The water reservoir 17 is connected to the water supply network 6 through the water supply pipe 7 in the transport channel 9.
[0062] The other high-level water tanks are similar, with a height difference of about 46 meters with the road surface in service tunnel 17, 46 meters with the 35-2# high-level water tank, and 64 meters with the road surface in service tunnel 17. The 3# tunnel section and the 4# tunnel section (starting tunnel section) share the 35-3# high-level water tank, and the 35-1# and 35-2# high-level water tanks supply fire-fighting water to the water supply network 6 of the corresponding tunnel sections in the left tunnel 14 and the right tunnel 16. The 35-3# high-level water tank supplies fire-fighting water to the water supply network 6 of the 3# tunnel section and the 4# tunnel section. All of them are gravity flow constant high-pressure water supply, and the water source is taken from the structural seepage in the tunnel, that is, the structural seepage collected by the drainage ditch 20 in the lower pipe gallery of the service tunnel 17. To ensure the reliability of the water supply system.
[0063] In each tunnel section, a water intake 28 and a water supply 29 are set at each water storage tank 27, which are used to fill the high-level water tank 4 and the water storage tank 27 with water by a water truck when the high-level water tank 4 lacks water after power failure. The overflow and drainage of the low-level water tank are all discharged from the drainage ditch 20 of the lower pipe gallery 18 of the horizontal pilot tunnel, and the overflow and drainage of the high-level water tank 4 are discharged from the drainage ditch 12 of the transportation channel 9. The transportation channel 9 and the high-level water tank cavern 11 are equipped with supporting ventilation, lighting and drainage systems.
[0064] The advantages of this water supply scheme are: gravity flow constant high pressure water supply, eliminating the fire pump room, one-time investment in water tank civil construction, water supply network 6 is kept with water all year round, water pressure is stable, water comes out when the fire hydrant is opened, no pressurization and personnel supervision are required, the water supply system is reliable and not affected by low temperature freezing and icing outside the tunnel, the water supply system is safe, the pressure in the pipeline is much lower than 1.9MPa, and no casualties will be caused during use, the water supply pipeline 7 and the water supply pipeline 10 are short in length, if the slope of the transport pipeline is 16°42", the length of the water supply pipeline is 162.7~226.4m, the cost is low, and it only takes 162.7~226.4m to transport the water in the reservoir 27 to the high temperature pool 4. The pipeline resistance is small, the workload of later maintenance and management is small, the water transmission operation cost is low, and the water source is taken from the structural seepage in the tunnel. The structural seepage is relatively stable and reliable, and can meet the requirements of fire water.
[0065] Example 2: Water supply scheme using low-level fire water tank + constant pressure fire pump set in parallel pilot tunnels
[0066] According to the main data, a service tunnel 17 for evacuation and rescue is set between the left tunnel 14 and the right tunnel 16. The service tunnel 17 is parallel to the lower pipe gallery 18 of the pilot tunnel and is provided with a drainage ditch 20 of the main structure under the road surface. The excavated space can be used to set up a fire pool 2 and a pump room 3. The water supply network 6 in the left tunnel 14 and the right tunnel 16 is divided into 4 zones. The fire pool 2 is arranged at the low point of each zone in the drainage ditch 20. The fire pool 2 is connected to the water supply network 6 through the pump room 3 and the water supply pipe 10. The zone pile number is the same as that in Example 1. The 1st, 2nd and 3rd zones are each provided with a 400 cubic meter fire pool 2 and a set of constant pressure fire pump group 3. The 4th zone shares the fire pool and constant pressure pump group of the 3rd zone. When a fire occurs, the constant pressure fire pump group 3 draws water from the fire pool 2 and pressurizes it to supply fire water to the water supply network 6 in the tunnel. The water source is the structural seepage of the tunnel, that is, the water collected in the drainage ditch 20. The overflow and drainage water of the fire water tank 2 are all discharged to the drainage ditch of the horizontal pilot tunnel.
[0067] The advantages of this water supply scheme are: the fire water tank 2 is arranged in the parallel guide tunnel, does not occupy the external space, and the construction and maintenance of the fire water tank, the pump room and the water supply pipeline are relatively easy.
[0068] The disadvantages of this water supply scheme are: the water supply system is a stable high-pressure water supply system. The pressure of the water supply network is usually maintained by a pressure-stabilizing pump. In the event of a fire, mechanical pressurization is required to provide sufficient water volume and water pressure to the tunnel water supply pipeline. In order to maintain the water supply pipeline with pressure all year round, the pressure-stabilizing pump needs to be turned on all year round, which consumes a lot of electricity. In addition, the fire pump room is located in the pipe gallery space on the lower level of the parallel guide tunnel, with poor ventilation conditions, dark and humid. The water pump unit is prone to rust and corrosion. The main pump and the pressure-stabilizing pump are prone to damage. The fire water supply pump unit needs regular maintenance and inspection, and the later maintenance and management costs are high. The water supply safety and reliability are poor, especially after a fire in the tunnel, there may be a power outage at any time. The electric-driven pressure-stabilizing pump is used in the tunnel to maintain the water supply pressure, which has low reliability.
[0069] Example 3: Water supply scheme combining high-level water tanks set up next to three ventilation shafts and high-level fire-fighting water tanks set up in parallel pilot tunnels
[0070] The difference between this water supply scheme and Example 1 is that four 400-cubic-meter high-level water tanks are set in the parallel pilot tunnel of the service tunnel to replace the high-level water tank in the high-level water tank cave in Example 1. Since the longitudinal slope of this tunnel and the service tunnel is very long, the height difference between the highest point and the lowest point in the tunnel reaches more than 230 meters, so the natural pressure generated by the height difference of the longitudinal slope of the tunnel can be fully utilized, and the high-level water tank is set at a suitable position in the parallel pilot tunnel of the tunnel. After calculation, the high-level water tank of each partition is set at 4,000 meters away from the lowest point of the partition. The lower corridor of the parallel pilot tunnel of the service tunnel is also arranged with drainage ditches and a water reservoir at the low point. A submersible booster pump is arranged in the water reservoir, and water is sucked by the submersible booster pump. Water is supplied to the high-level water tank in the service tunnel through the water supply pipeline that rises in the reverse direction along the longitudinal direction of the service tunnel. The high-level water tank is connected to the water supply pipeline in each partition.
[0071] The advantages of this water supply solution are: the entire water supply system is a constant high-pressure gravity flow water supply solution.
[0072] The disadvantages of this water supply scheme are: the water supply system is divided into four zones, among which the four high-level water tanks in the service tunnel supply water to the first zone, the second zone, the third zone and the fourth zone respectively. A total of 4000*2*4=32000 meters of DN200 pipes are required, there are too many repeated pipes between the zones, the cost of the pipes is higher, and the water supply pipes from the high-level water tank to the reservoir are too long, there are too many pipe joints, too many faults and leaks, the pipe laying is complicated, and the water supply safety and reliability are very poor. When there is a power outage in the tunnel, the time required to transport water from the reservoir to the high-level water tank by a water truck is more than 20 times longer than that of Example 1. Firefighting is urgent in the event of an emergency, and extending the water transportation time will cause greater disaster losses.
[0073] Example 4: Water supply scheme using a high-level water pool set up on the inner wall of a ventilation shaft
[0074] Compared with Example 1, the position of the high-level water tank in this water supply scheme is completely adjusted to the cavern excavated on the inner wall of the ventilation shaft 35. The advantage of this water supply system is that the system cost is relatively low, and the disadvantage is that there is no dedicated transportation channel and maintenance access road. In an emergency, the water inlet pipe and the outlet pipe of the high-level water tank must be laid and fixed along the side wall of the ventilation shaft, which is inconvenient for installation and maintenance. The management personnel can only go up and down the ladder of up to 40 to 70 meters set on the side wall of the ventilation shaft to inspect the high-level water tank, which has a high risk factor, and the power distribution, lighting, drainage and other facilities of the high-level water tank cavern are difficult to install.
[0075] After comparison, Example 1 is recommended for the water supply system of Tianshan Tunnel.
[0076] The cross-sectional width of the transport passage leading to the high-level water tank is 4.7m; the clearance height is 6.2m;
[0077] The slope of the transport channel leading to the high-level water tank is not more than 30%;
[0078] The area of the high-level water pool cavern is: 20m (length) × 12.5m (width);
[0079] The cross-sectional width of the high-level water tank cavern is: 12.5m; the clear height is 9.25m;
[0080] The size of the high-level water tank and the drainage ditch of the transport channel is 15cm×15cm;
[0081] The height difference of the road surface at both ends of the tunnel is greater than 198.89m. When the longitudinal slope of the tunnel is 0.836%~2%, the longitudinal slope length of the tunnel is greater than 9.89km.
Claims
1. A fire water supply system for an ultra-long tunnel, comprising a tunnel and a service tunnel, wherein the tunnel is parallel to the service tunnel, and is characterized in that: The height difference of the road surface at both ends of the tunnel is greater than 198.89m, the longitudinal slope is not more than 2%, and the longitudinal slope length is greater than 9.89km. The temperature in the mountainous area outside the tunnel is lower than 0℃ all year round, and the thickness of frozen soil in the mountainous area is greater than 3 meters. The tunnel has a lining built with permeable materials and a road surface paved with waterproof materials. The service tunnel has a lower pipeline gallery road surface lower than the tunnel road surface and a drainage ditch lower than the lower pipeline gallery road surface. The side wall of the tunnel is connected to the service tunnel through a downward inclined transportation channel. The tunnel and service tunnel are divided into several types according to the ventilation shaft. In the dry tunnel section, a water reservoir is set at the low point of the drainage ditch in each tunnel section. The service tunnel in each tunnel section is connected to the high-level water tank cavern through a transportation channel. The height difference between the floor of each high-level water tank cavern and the high point of the tunnel floor in each tunnel section is H, H=30~100m. A high-level water tank is arranged in each high-level water tank cavern. A water supply pipe connecting the high-level water tank and the submersible booster pump arranged in the water reservoir is laid in the transportation channel. Each high-level water tank is connected to the water supply network arranged in the corresponding tunnel section through a water supply pipe to provide fire-fighting water; In each tunnel section, a water intake and water supply port shall be set at each water reservoir to facilitate water tankers to take water from the water reservoir and supply water to the water reservoir; The slope of the transport channel is no more than 30%, which makes it convenient for water tankers to transport water to the high-level water tank through the transport channel.