WO2021063295A1 - Fire-fighting water supply system for super-long tunnel - Google Patents

Abstract

Disclosed is a fire-fighting water supply system for a super-long tunnel. The fire-fighting water supply system is specially designed for a high-cold, high-altitude, super-long tunnel such as Tianshan tunnel, wherein "intra-tunnel elevated tanks" are arranged at appropriate positions in the tunnel, a tunnel pipe network is reasonably partitioned, each elevated tank supplies tunnel fire-fighting water for a corresponding partition, and the super-long tunnel is virtualized into a plurality of "short tunnels", such that the problem of pipe network overpressure caused by static height difference in the tunnel being too large is solved, and the complex problem is effectively routinized and simplified. In addition, the ambient temperature in the tunnel is higher than that outside the tunnel, fire-fighting facilities such as the elevated tanks and pipelines in the tunnel, which are at a certain distance away from a tunnel entrance, barely have the problem of freezing, and structural water seepage in the tunnel can be fully used, thereby solving a series of problems such as the freezing of water sources, elevated tanks, lower tanks and pipelines when elevated tanks and lower tanks are arranged outside a tunnel.

Description

A fire-fighting water supply system for an ultra-long tunnel Technical field

The invention belongs to the technical field of fire protection systems for ultra-long highway tunnels, and more specifically relates to a fire-fighting water supply system for ultra-long tunnels, which is suitable for the water supply of the fire-fighting system for ultra-long highway tunnels.

Background technique

As a basic part of the highway route, highway tunnels develop simultaneously with highway construction. Western construction has been the focus of the country's infrastructure construction in recent years, and its high altitude and cold have become a major difficulty in design and construction. The design of the fire water supply system for 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 a constant high-pressure water supply system with a high-level fire-fighting pool as shown in Figure 1, and a stable high-pressure fire-fighting water supply system with a low-level fire-fighting pool and air pressure water supply equipment as shown in Figure 2.

A constant high pressure water supply system with a high-level fire-fighting pool outside the tunnel usually includes a water source 1, a low-level reservoir 2, a water pump house 3, a water storage pipeline connected to the high-level pool 4 in sequence, and a water supply connected to the high-level pool 4 through a water supply pipe 5. The schematic diagram of the pipe network 6 is shown in Fig. 1. The water source 1 usually uses one or a combination of municipal tap water, deep well water, mountain stream, river water, surrounding rock seepage water, or spring water. Low-level reservoir 2 and pump house 3 are usually set near the tunnel entrance, high-level reservoir 4 is set on the mountain at one end of the tunnel where low-level reservoir 2 is located, and the bottom elevation of low-level reservoir 2 must meet the design elevation. Water supply pipe network 6 Located in the tunnel. The advantage of this water supply system is that there is a natural height difference between the high-level pool 4 outside the tunnel and the water supply pipe network 6 inside the tunnel that meets the design requirements, and the system forms a constant gravity flow water supply. Once the fire hydrant is opened, the design pressure and flow can be met Fire water consumption and water supply are safe, stable and reliable. The disadvantage is that the high-level pool 4 is usually located on a mountain with a height of 50m or more near the entrance of the tunnel, and facilities such as up and down water supply pipelines 5 and access roads need to be installed. Additional land acquisition is required, which may damage vegetation and cause landslides and other risks.

The stable high-pressure water supply system outside the tunnel usually includes a water source 1, a low-level reservoir 2, a water pump house 3, and a water supply pipe network 6. The schematic diagram is shown in Figure 2. The water source 1 usually uses municipal tap water, deep well water, and mountain water. One or a combination of streams, river water, wall rock seepage water, or spring water. The low-level reservoir 2 and the water pump house 3 are usually set near the tunnel entrance. The pump room 3 is equipped with pneumatic water supply equipment, and the water is directly supplied to the water supply pipe network 6 in the tunnel after the low-level reservoir 2 absorbs and pressurizes. The advantage of this water supply system is: Compared with the constant high pressure water supply system, the system only needs to set up a low-level reservoir 2 and a set of air pressure water supply equipment at the tunnel entrance, and does not need to set up a high-level pool 4, maintenance access roads, up and down mountain water supply pipelines Grade 5 facilities reduce the relatively low cost of pipeline laying, occupy less land, and cause less damage to the environment. The disadvantage is that the system usually uses air pressure water supply equipment to stabilize the water supply pipe network 6. When a fire occurs, the fire main pump must be turned on to provide the fire water consumption that meets the design flow and pressure requirements. The air pressure water supply equipment needs to be turned on all the year round. Pump failure or power failure will not be able to provide the fire water consumption that meets the design flow and pressure requirements, the safety and reliability of the water supply is low, the later operation and maintenance management workload is large, and the electricity bill is high.

For conventional highway tunnels, the tunnel fire water supply system should be given priority to using a constant high pressure water supply system with a high-level pool 4 outside the tunnel. When a high-level pool 4 is unconditionally installed, a stable high-pressure water supply system can be used.

For high-cold and high-altitude highway tunnels, the method of setting the fire-fighting equipment outside the tunnel below the freezing line is usually adopted to achieve the purpose of anti-freezing and heat preservation. However, because the high-level pool is usually high in elevation and deep in the freezing line, construction is difficult. It shows that the permafrost layer on the northern slope of Kunlun Mountain on the Qinghai-Tibet Highway and the Anduo area in northern Tibet is 80-100 meters thick, and the depth of frozen soil in the hinterland of the Tianshan Mountains has reached more than 4 meters. Therefore, such tunnels generally use a stable and high-pressure water supply system for fire protection in the tunnel Water supply through pipe network.

With the rapid advancement of infrastructure construction in the western part of the country, more and more high-cold and high-altitude road tunnels have emerged. In terms of route selection, in order to greatly shorten the length of the entire route, many super-long tunnels of more than 5km, or even 10km, will appear in some projects. The above-mentioned super-long tunnels, the typical characteristics of this kind of super-long tunnels are that the tunnel is long and the static height difference in the tunnel is large. For the design of the tunnel fire-fighting system, there are also the problems of anti-freezing and heat preservation of fire-fighting equipment and facilities, which are difficult to solve. Take the Wei Expressway as an example to illustrate the important and difficult points of this kind of tunnel fire protection system design.

The construction starting point of Xinjiang Wuwei Expressway Project is located on the west side of the G30 Cangfanggou Interchange Interchange in Urumqi City. It is connected to the planned West Ring Expressway Xishannan, and partially uses the built G216 first-class highway as the main line of the project. The route generally flows from north to south along the Daxigou River, passing through Yongfeng Township, Qianxia and Houxia along the way, and set up an extra-long tunnel at Wangfeng Road to pass through Shengli Daban, enter Hejing County, and follow Ustogou to Ulas Taiwan, followed by the'Ulastai River' and the'Habqiha River' downstream, passing Shengli Bridge, Barentai, Jinte Iron and Steel Plant to Huangshuigou Hydrological Station, and then into the Gobi Plain, passing 21 Mission field west, Qixing Town east, cross Heku Expressway to Tashidian at Ziniquan, cross Kuluktag Mountain, cross Tuku Railway, route along the east side of Korla planning area, and stop at Yuli Qiongkule Village on the east side of the county.

其水消防系统的设计是隧道附属工程设计的关键。 The Tianshan ultra-long tunnel with a single hole length of about 21km is a super-large control project for this expressway. It is located at an altitude of more than 3000 meters.

The design of its water fire-fighting system is the key to the design of the tunnel ancillary engineering.

4)高寒、高海拔，达3000米以上，天山北坡历史平均气温2～3℃，冬季平均气温-10～-12℃、5)冻土线深，施工难度大，平均冻土深度约3米，局部冻土深度达到17米；6)隧道桥隧比高，洞口空间有限。 The main features of the tunnels along the line of this project are: 1) There are a large number of tunnels, with a total of 20 tunnels along the line; 2) Each tunnel is long, of which the Tianshan Tunnel is about 21km long; 3) The slope is gentle and sloped

4) High cold and high altitude, above 3000 meters, historical average temperature on the northern slope of Tianshan Mountain is 2～3℃, winter average temperature is -10～-12℃, 5) Frozen soil line is deep, construction is difficult, and the average frozen soil depth is about 3 Meters, the depth of local frozen soil reaches 17 meters; 6) The tunnel bridge-tunnel ratio is high, and the opening space is limited.

In view of the characteristics of the project, the preliminary difficulties in the design of the fire protection system of the conventional tunnels along the project line are as follows: 1) The choice of the water supply system outside the tunnel, whether to install a constant high pressure system or a stable high pressure system. 2) This project has a large number of tunnels and a high bridge-to-tunnel ratio, and most of the tunnel openings do not have the conditions for the construction of water pump houses and fire pools. 3) The freezing season at the project site is long and the frozen soil is deep. It is difficult to solve the problem of anti-freezing and heat preservation of equipment and facilities such as fire pools, pump rooms, and fire pipelines outside the tunnel. 4) Choose surface water or groundwater as the water source for tunnel fire protection.

For the Tianshan tunnel with a single tunnel length of about 21km, in addition to the above-mentioned difficulties in the design of the fire protection system, there are also the following preliminary design difficulties:

1. There is no suitable fire-fighting water source outside the tunnel

The fire-fighting water source of conventional project tunnels usually uses one or a combination of municipal tap water, surface water (mountain stream, river water, surrounding rock infiltration water or spring water), and ground water (deep well water).

For the Tianshan ultra-long tunnel, there is no municipal tap water near the tunnel. If surface water outside the tunnel (mountain stream, river water or spring water) is used, the surface water will freeze in winter, the water pipeline is buried too deep, and the laying is difficult; If groundwater is used, there are problems such as the depth of groundwater buried in the water source, the buried water pipeline is too deep, and it is difficult to lay the groundwater. In addition, the biggest problem with setting up firefighting water sources outside the tunnel is that both surface water sources and underground water sources must be equipped with submersible pressurized pumps to transport water into the tunnel. The maximum static height difference in the Tianshan tunnel reaches 235m, resulting in the maximum possible lift of the submersible pressurized pump At more than 300 meters, the water pipeline cannot withstand such a large pressure.

2. Conventional fire water supply system is difficult to implement in this project

1) Constant high pressure water supply system outside the tunnel

According to the "Code for Design of Highway Tunnels Part Two Traffic Engineering and Auxiliary Facilities" (JT D70/2-2014), the tunnel fire water supply should adopt a high-level fire-fighting pool water supply constant high-pressure water supply system; when the high-level pool is unconditionally set up, a stable high-pressure water supply system can be used water supply system. The conventional tunnel fire water supply system in highway tunnels is usually a constant high pressure and stable high pressure water supply system outside the tunnel. The tunnel is located in a high-cold area. If a constant high pressure water supply system outside the tunnel is used, the fire-fighting pipe network in the tunnel is divided into two zones at most and two ring networks. The high-level pools at both ends of the tunnel supply one zone of fire-fighting water, but the largest in the tunnel The static height difference is as high as 235m (the vertical side is a herringbone slope). According to hydraulic calculations, the high-level pool at the small pile end of the tunnel provides reverse and upward slope water supply for the pipe network in the tunnel. The bottom elevation of the pool must overcome a height difference of 150 meters and a height of 10 kilometers. In addition to the head loss and the water supply pressure at the most unfavorable point of 40 meters, the height difference between the bottom of the high-level pool and the tunnel opening is as high as about 250 meters, and this high-level pool cannot be installed. The high-level pool 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 the most unfavorable point of 40 meters. It should be installed on a high mountain with a height difference of at least 100 meters from the entrance of the tunnel. According to the main information, the extreme minimum temperature in the tunnel site area is -43.4℃, the average frozen soil depth is about 3 meters, and the local frozen soil depth reaches 17 meters. It is difficult to implement the conventional method of burying high-level pools below the frozen soil line to achieve anti-freezing and thermal insulation. In addition, the high-level pool is usually located on a mountain, and the construction is very difficult due to the steep terrain and icing of the overlying soil. Similarly, the anti-freezing problem of the upper and lower water supply pipelines is also difficult to solve. Even if a short section of the pipeline system is frozen, the entire pipeline will not be able to pass water, and the reliability of the water supply is very low. Considering the above factors, the constant high pressure water supply scheme outside the tunnel is not feasible.

2) Stable high-pressure water supply system outside the tunnel

The external stable high-pressure water supply system of the tunnel, that is, the water supply scheme that uses the pneumatic water supply equipment installed near the tunnel entrance to absorb water from the low-level reservoir and directly pressurize the tunnel fire-fighting water. For general road tunnels, the internal pipe network of the high-pressure water supply system is stabilized. Usually it is a large ring network, the water supply system is a zone, and the water supply pump group directly sucks water and pressurizes to supply the ring network. The Tianshan Tunnel is a single-slope tunnel with a length of about 21km. The height difference between the two ends of the tunnel is about 235m. If only a large ring network is installed in the tunnel, the water supply main pipe in the tunnel is DN200, and the water supply pressure at the most unfavorable point of the tunnel is 0.4 Calculated by MPa, the hydrostatic pressure at the farthest point of the tunnel reaches 2.35 MPa, and the dynamic pressure of the water supply reaches 1.9 MPa, which exceeds the nominal pressure of the conventional fire main pipe (steel pipe) by 1.6 MPa. If a pipe with a higher nominal pressure is used (for example, 2.5 MPa) , It is easy to cause accidents such as pipeline leakage or even pipe bursting, and the water outlet pressure of the fire hydrant is too high, it is difficult to control the operation during fire fighting, and even accidentally injure firefighters and endanger the operation safety of the tunnel.

To sum up, for the Tianshan ultra-long tunnel with a length of about 21km, it is located above 3000 meters above sea level, with frozen soil all year round, the average frozen soil depth is about 3 meters, the local frozen soil depth reaches 17 meters, and the slope is gentle. According to the conventional design, a constant high pressure or stable high pressure water supply system such as high and low pools, pump houses, pipe networks, etc. are directly installed outside the tunnel. First, there are major problems with fire fighting water sources: surface water will freeze, and 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; the second is that it is difficult to solve the antifreeze problem of the high and low pools, the pump room, and the pipes outside the tunnel; the third is if the high and low pools are set outside the tunnel, the water inside the tunnel The pipe network is divided into two areas. The elevation of the bottom of the high-level pool will be very high. The static and dynamic pressure of the pipe network in the tunnel is too high, which may easily cause accidents such as pipeline leakage and even pipe burst, which endangers the safety of tunnel operation. The fire-fighting water supply system scheme of conventional road tunnels cannot be implemented in the Tianshan Tunnel, which is an extremely long tunnel with high cold and high altitude.

Summary of the invention

The technical problem to be solved by the present invention is to provide a fire-fighting water supply system for an ultra-long tunnel with a length of more than 9.89km, a height difference of more than 198.89m, a long-term environmental temperature of less than 0°C, and a frozen soil depth of more than 3 meters. Simple and easy to use, it solves the problem of freezing fire pools due to low ambient temperature, the difficulty of excavating and construction of thick frozen fire pools in high altitude areas, the large height difference in the tunnel, and the static pressure overpressure in the fire pipe network. Provide the fire-fighting water supply system with the lowest construction and maintenance cost.

In order to achieve the above objectives, the present invention adopts the following technical measures:

A fire-fighting water supply system for an ultra-long tunnel, comprising a tunnel and a service tunnel, the tunnel is parallel to the service tunnel, the height difference of the pavement at the two ends of the tunnel is greater than 198.89m, the longitudinal slope gradient is not greater than 2%, and the longitudinal slope length is greater than 9.89 km, the temperature in the mountainous area outside the tunnel is below 0℃ all the year round, and the thickness of frozen soil in the mountainous area is greater than 3 meters. The tunnel has a lining made of permeable materials and a pavement paved with water-proof materials, and the service tunnel has a lower surface than the tunnel pavement. The lower pipe gallery road surface and the drainage ditch lower than the lower pipe gallery road surface, the side wall of the tunnel is connected to the service tunnel through the inclined downward transportation channel. The tunnel and the service tunnel are divided into several tunnel sections according to the ventilation shaft. A reservoir is set at the low point of the drainage ditch in each tunnel section, and the service tunnel in each tunnel section is connected to the high-level tank cavern through the transportation channel. The ground of each high-level tank cavern is higher than the tunnel ground in each tunnel section. The height difference of the point position is H, H=30-100m. Each high-level pool is equipped with a high-level pool, and the transportation channel is equipped with a water pipeline connecting the high-level pool and the submersible pump arranged in the reservoir. Each high-level pool The water supply pipe network arranged in the corresponding tunnel section is connected with the water supply pipe to provide fire fighting water.

Furthermore, in each tunnel section, a water intake and a water supply port are provided at each reservoir to facilitate the water truck to take water from the reservoir and supply water to the reservoir.

Further, the gradient of the transportation channel is not more than 30%, which is convenient for the water truck to transport water to the high-level pool through the transportation channel.

为纵坡倾斜角，起始隧道区段与相邻隧道区段内的两段供水管网共用连通该相邻隧道区段对应的高位水池，该高位水池所在高位水池洞室地面与起始隧道区段内的隧道地面高点位置的高度差

L为起始隧道区段的长度。 Further, the longitudinal gradient of the initial tunnel section located at the initial opening of the tunnel among the tunnel sections is smaller than the longitudinal gradient of the remaining tunnel sections, wherein

It is the inclination angle of the longitudinal slope. The two water supply pipe networks in the initial tunnel section and the adjacent tunnel section share the high-level pool corresponding to the adjacent tunnel section. The height difference of the high point position of the tunnel on the ground in the section

L is the length of the initial tunnel section.

The present invention takes the Tianshan Tunnel of Xinjiang Wuwei Expressway as an example. The technical idea is that three ventilation shafts are set in the tunnel. With reference to the ventilation system using the ventilation shafts for partitioning (4 sections), the fire water supply system is also Divided into 4 zones, the range of the zone number is the same as that of the ventilation system (the ventilation zone is more uniform). The idea is to excavate 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 cave room where the high-level pool is located. 1# high-level pool (that is, set in 1# ventilation shaft The height difference between the high-position pool next to it and the other high-position pools is the same) and the ground in the tunnel is about 46 meters, the height difference between the 2# high-position pool and the ground in the tunnel is about 46 meters, and the height difference between the 3# high-position pool and the ground in the tunnel is about 64 meters. Section 3 and Section 4 share high-level water pools), three high-level fire-fighting water pools supply the fire-fighting water for the 4 districts in the tunnel, and supply water for gravity flow and constant high pressure. The water source is taken from the structural seepage in the tunnel, that is, the lower pipe of the tunnel flat guide tunnel is used. The structure collected by the drainage ditch in the corridor sees water, and a reservoir is set in the appropriate position of the lower pipe corridor, and a submersible pressurized pump is set in the reservoir to pump the water source to the high-level pool. In order to ensure the reliability of the water supply system, it is planned to set up water intake and water supply port at each low-level pool in the design to use water trucks to fill or fetch water from the reservoir under extreme water shortage conditions. The overflow and discharge of the reservoir are drained from the drainage ditch in the lower layer of the guide tunnel, and the overflow and discharge of the high-level pool are drained from the drainage side ditch of the transportation channel. The transportation channels and high-level pools are equipped with supporting air supply and exhaust, lighting systems and drainage systems.

The section width of the transportation channel is: 4.7m; the clearance height is: 6.2m;

The slope of the transportation channel is not more than 30%;

The area of the cavern is: 20m (length)×12.5m (width);

The section width of the cavern is: 12.5m; the clearance height is 9.25m;

The size of the high-level pool and the drainage side ditch of the transportation channel is 15cm×15cm.

The high-level pools are equipped with inlet pipes, outlet pipes, vent pipes, overflow pipes, vent pipes, high and low-level pools attached inspection holes, iron ladders, wall-through pipes, wall-through pipe reinforcement, water pipe hangers, See "Rectangular Reinforced Concrete Reservoir" (05S804) for ventilation holes. A grille is installed at the entrance and exit of the low-level reservoir to prevent floating objects from blocking the pipeline. The elevation of the bottom of the high-level pool can make the most unfavorable point of the tunnel water supply pipe network have a pressure of not less than 0.4 MPa. The water in the reservoir is lifted to a high-level pool by a water pump, and then the high-level pool supplies water to the tunnel ring-shaped water supply network through two outlet pipes. The pipe network is kept in a state of constant water and can be put into use in the event of a fire.

The high-level pool is equipped with a lightning-proof stainless steel fire-fighting pool level sensor, which is used for ultra-high and ultra-low water level alarms. The alarm signals are transmitted to the control cabinet, and the control cabinet controls the start and stop of the water pump. When the water level drops to the lowest water level threshold, the submersible booster pump is started to replenish water, and when the water level rises to the highest water level threshold, the submersible booster pump is stopped to replenish water. The submersible pressurized pump control cabinet is set in the submersible pressurized pump well room, and the submersible pressurized pump is soft-started and has a low-frequency automatic cycle inspection function; the submersible pressurized pump control cabinet communicates with the pump house PLC through optical fiber and is controlled by the PLC; high-level pool The control cable of the water level sensor is arranged with the DN100 water pipeline.

The outlet pipe of the submersible booster pump is equipped with a remote pressure gauge to monitor whether the water supply pressure is normal when the pump is working, and a liquid level sensor is installed in the deep well for real-time water level changes. All collected data is sent to the water pump control cabinet.

The air supply and exhaust system is an axial fan + air duct system installed in the transportation channel and the high-level pool cave.

The said lighting system is equipped with LED lighting system and emergency lighting system in the transportation channel and in the high-level pool cave.

The said drainage system is to set drainage side ditches in the caverns of the high-level pool and the transportation channel to guide the structural seepage to the drainage ditch of the service tunnel, while the overflow water and empty water of the high-level pool are diverted to the drainage ditch of the service tunnel.

The feature of the present invention is that the maximum height difference in the tunnel is about 235m, the "high-level pool in the tunnel" is set at a suitable position in the tunnel, and the tunnel fire-fighting pipe network is reasonably partitioned, and each high-level pool supplies the corresponding partition of the tunnel fire-fighting water. The water supply system of the super-long tunnel is divided into several "short tunnels", which solves the problem of overpressure in the pipe network caused by the excessive static height difference in the tunnel. In addition, the ambient temperature in the tunnel is higher than that outside the tunnel, and the tunnel is a certain length away from the entrance of the tunnel. There is almost no problem of freezing of water supply pipelines in the tunnel, and the structural water seepage in the tunnel can also be fully utilized to provide water for the fire fighting pipeline. More importantly, the "high-level pool in the tunnel" is installed in the high-level pool cave. The interior and the tunnel are connected through the transportation channel. When the water supply to the high-level pool fails, water can be supplied to the high-level pool through the transportation channel through the water transportation vehicle. The maintenance personnel can also enter the high-level pool cavity 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 pipeline connecting the high-level pool is the lowest, and the maintenance cost is the lowest.

Compared with the prior art, the present invention is the industry's first design for highway tunnel fire protection, and its main advantages are:

(1) In terms of water supply safety and reliability: the entire Tianshan Tunnel adopts gravity flow constant high pressure water supply. The pipe network maintains water throughout the year, the water pressure is stable, and the water is discharged when the fire hydrant is opened. There is no need for pressurization and personnel supervision. The water supply system is safe and reliable. The management workload is small. In addition, the fire-fighting pipe network in the tunnel provides water supply in districts. Each pipe network is relatively independent. The static height difference of 235m across the entire line is spread to three ring networks, and the static height difference of each ring network is about 65m, which greatly reduces the excess of the pipe network. The risk of pressure water supply. The water source is taken from the structure seepage in the tunnel. The water seepage of the structure is relatively stable and reliable, which can meet the requirements of fire fighting water.

(2) Anti-freezing and heat preservation: The high and low-level pools, water sources, and submersible pressurized pumps of the Tianshan Tunnel are all set in the tunnel. The temperature inside the tunnel is higher than that outside the tunnel. There is no risk of freezing and freezing of fire-fighting equipment and facilities. Additional anti-freezing and heat preservation measures are provided.

(3) In terms of construction difficulty: high and low water pools, and transportation channels are all constructed in the tunnel, which is implemented synchronously with the main civil works of the tunnel. The civil construction unit takes overall consideration of the construction method and technology to avoid avalanches and landslides caused by the second excavation of the mountain outside the tunnel. , Damage to the environment and other risks, greatly reducing the difficulty of construction.

(4) In terms of economy: the fire pump house and the external thermal insulation material of the tunnel are omitted, the civil construction of the pool requires one investment, and each zone only needs to build a transportation channel and a high and low pool, which greatly reduces the project investment, and in the later stage It is easy to maintain and has incomparable economy.

(5) Environmental protection: The project is located in the secondary water source protection area and the glacier protection area. Building a pool at the tunnel entrance will not only destroy the glacier and cause the imbalance of the local ecological environment, but also the waste generated by the construction of the pool will easily cause water pollution. .

Therefore, the present invention is of great significance for my country to promote the construction of high-cold and high-altitude ultra-long highway tunnels, to solve the design problems of auxiliary projects, to improve the reliability of tunnel disaster prevention and rescue, and to promote the overall development of my country's modern transportation industry.

Description of the drawings

Figure 1 is a schematic diagram of a constant high pressure water supply system;

Figure 2 is a schematic diagram of a stable high-pressure water supply system;

Figure 3 is a schematic diagram of a longitudinal section of an ultra-long tunnel fire-fighting water supply system;

Figure 4 is a clear cross-section view of the high-level pool transportation channel of an ultra-long tunnel fire water supply system;

Figure 5 is a cross-section view of the lining clearance of a high-level pool cavern of an ultra-long tunnel fire-fighting water supply system;

Figure 6 is a cross-section view of an ultra-long tunnel transportation tunnel, service tunnel and transverse tunnel;

Figure 7 is a general perspective view of an ultra-long tunnel fire-fighting water supply system.

The meanings of the numbers and symbols are as follows:

1—water source, 2—low-level reservoir, 3-pump house, 4-high-level pool, 5—downhill water supply pipeline, 6—water supply pipeline network, 7—water supply pipeline, 9—transportation channel, 10—water supply pipeline, 11 —High-level pool cavern, 12—drainage side ditch, 14—left tunnel, 16—right tunnel, 17—service tunnel, 18—lower pipe gallery, 20—drainage ditch, 28—water intake, 29—water supply port, 27 —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 The length is 6000m, the height difference is 53m, the horizontal length is 5km, the section L4#-4# has a length of 3555m, the height difference is 23m, and the horizontal length is 5km.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

The present invention takes the Tianshan Tunnel of Xinjiang Wuwei Expressway as an example to illustrate the specific implementation of the present invention.

Contents of the present invention The three water supply schemes before the determination are compared and selected as follows. Compared with other mandatory schemes, the technical scheme of the present invention has significant construction cost and maintenance cost advantages, which is not obvious:

Example 1: Scheme of setting up a high-level pool next to the ventilation shaft (optimal scheme)

As shown in Figure 6, the total length of the left tunnel 14 and the right tunnel 16 are both 21km. The height difference between the two tunnel ends is 235m, the slope is 0.26°～0.64°, and 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. The ambient temperature outside the tunnel is below 0℃ for a long time. The frozen soil layer outside the tunnel is more than 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. The lower pipe corridor of the service tunnel 17 is lower than the pavement 19 of the left tunnel 14 and the right tunnel 16. The pavement of the left tunnel 14 and the right tunnel 16 are on the side close to the service tunnel 17, each of which is inclined downwards The transportation channel 18 is connected to the service tunnel 17. The lower pipe corridor of the service tunnel 17 is provided with a drainage ditch 20 in the middle. The pavement of the left tunnel 14, the right tunnel 16 and the service tunnel 17 are paved with water-proof materials, and the left tunnel above the road 14, The structure of the lining 13 of the right tunnel 16 and the service tunnel 17 is permeable material, and the drainage ditch 20 is used to collect the structural water seepage on the top of the left tunnel 14, the right tunnel 16 and the service tunnel 17.

As shown in Figures 7 and 3, there are three ventilation shafts 35 in the left tunnel 14 and right tunnel 16. Referring to the ventilation system using the ventilation shaft 21 to partition (4 tunnel sections), the left tunnel 14, right The tunnel 16 is also divided into 4 zones, and the range of the tunnel section pile number is the same as that of the ventilation system (the ventilation zone is more uniform). In each tunnel section, excavate a transportation channel 9 from the service tunnel 17 to the high-level pool cavern 11, which is also used for pipeline laying sites, maintenance access roads, air supply and exhaust channels, etc., 4-1# high-level pool, that is Set up the high-level pool 4 in the high-level pool cavern 11 next to the 35-1# ventilation shaft 35, the service tunnel 17 and the lower pipe gallery 18, set a 400T capacity reservoir 27 and the reservoir 27 near the transportation channel 9. Set up a submersible pressurized pump to pump water along the upper water pipeline 10 in the transportation channel 9 to the high-level pool 4. The left tunnel 14, the right tunnel 16 and the transportation channel 9 are laid with an annular water supply network 6, and the reservoir 17 passes through the transportation channel 9. The inner water supply pipe 7 is in communication with the water supply pipe network 6.

The other high-level pools are similar, with a height difference of about 46 meters from service tunnel 17, 35-2# high-level pool and service tunnel 17 are about 46 meters high, 35-3# high-level pool and service tunnel 17 are about 46 meters high. Approximately 64 meters, 3# tunnel section and 4# tunnel section (starting tunnel section) share 35-3# high-level pool, 35-1# and 35-2# high-level pools are supplied to left tunnel 14 and right tunnel 16. Corresponding to the water supply pipe network 6 fire water of the tunnel section, 35-3# high-level pool supplies the water supply pipe network 6 of the 3# tunnel section and the 4# tunnel section to provide fire fighting water, all of which are gravity flow constant high pressure water supply, and the water source is taken from The structural water seepage in the tunnel refers to the structural water seepage collected by the drainage ditch 20 in the lower pipe gallery of the service tunnel 17 flat guide tunnel. To ensure the reliability of the water supply system.

In each tunnel section, a water intake 28 and a water supply port 29 are provided at each reservoir 27, which are used to fill the upper reservoir 4 and reservoir 27 with water trucks when the upper reservoir 4 lacks water after the power is cut off. . The overflow and discharge of the low-level pool are discharged from the drainage ditch 20 of the lower pipe gallery 18 of the flat guide tunnel, and the overflow and discharge of the high-level pool 4 are discharged from the drainage side ditch 12 of the transportation channel 9. The transportation channel 9 and the high-level pool cavern 11 are equipped with supporting air supply and exhaust, lighting systems and drainage systems.

The advantages of this water supply scheme are: gravity flow constant high pressure water supply, eliminating the need for a fire pump house, a one-time investment in the civil construction of the pool, water supply pipe network 6 maintains water throughout the year, stable water pressure, water can be discharged when the fire hydrant is opened, no need for pressure and personnel The care and water supply system is reliable and not affected by low-temperature freezing outside the tunnel. The water supply system is safe. The pressure in the pipeline is much lower than 1.9MPa, which will not cause casualties when used. The length of the water supply pipeline 7 and the water supply pipeline 10 is short, and the transportation pipeline If the slope is 16°42", the length of the water supply pipeline is 162.7-226.4m, the cost is low, and the water in the reservoir 27 is transported to the high-temperature pool 4, only 162.7-226.4m pipeline resistance is small, and the later maintenance and management workload Small, low water delivery cost, and the water source is taken from the structure seepage in the tunnel. The structure seepage is relatively stable and reliable, and can meet the requirements of firefighting water.

Example 2: Water supply scheme using low-level fire-fighting pool + constant-pressure fire-fighting pump set in parallel pilot tunnels

According to the main information, a service tunnel 17 for evacuation and rescue is set between the left tunnel 14 and the right tunnel 16. The main structure drainage ditch 20 is set under the road surface of the service tunnel 17 parallel to the lower pipe gallery 18 of the pilot tunnel, and the excavation Fire pool 2 and water pump room 3 can be installed in the space of, the water supply pipe network 6 in the left tunnel 14 and right tunnel 16 can be divided into 4 areas. The fire pool 2 is arranged in the drain 20 at the low point of each area, and the fire pool 2 The water supply pipe network 6 is connected through the water pump house 3 and the water supply pipeline 10, and the zone number is the same as that of Example 1. The first, second, and third zones are equipped with a 400 cubic meter fire pool 2 and a set of constant pressure fire pump set 3. The 4th zone shares the fire-fighting pool and the constant pressure pump set of the 3rd zone. In the event of a fire, the constant pressure fire pump set 3 sucks water from the fire pool 2 and pressurizes it to supply the fire fighting water to the water supply pipe network 6 in the tunnel. The water source is taken from the structural seepage of the tunnel, that is, the water collected in the drainage ditch 20, and the overflow and discharge water of the fire pool 2 is discharged to the drainage ditch of the flat guide tunnel.

The advantages of this water supply scheme are: the fire water tank 2 is set in the parallel guide tunnel, does not occupy external space, and the construction and maintenance of the fire water tank, the water pump house, and the water pipeline are relatively easy.

The shortcomings of this water supply scheme are: the water supply system is a stable high-pressure water supply system, and the pressure of the water supply pipe network is maintained by the pressure-stabilizing pump at ordinary times. In the event of a fire, mechanical pressure is required to provide sufficient water volume and pressure for the tunnel water supply pipeline. In order to maintain the pressure of the water supply pipeline all year round, the stabilized pump needs to be turned on all year round, which consumes a lot of power, and the fire pump room is set in the pipe gallery space under the parallel pilot tunnel. The ventilation conditions are poor, dark and humid, and the pump unit is easy to rust and corrode. Both the pump and the stabilized pump are easily damaged. The fire water supply pump set requires regular maintenance and overhaul. The subsequent maintenance and management costs are high, and the safety and reliability of the water supply is poor. Especially after the tunnel is fired, the power may be cut off at any time. The tunnel is driven by electricity. The stabilized pump maintains the water supply pressure and has low reliability.

Example 3: A water supply scheme combining high-level pools set beside 3 ventilation shafts + high-level fire-fighting pools in parallel guide tunnels

The difference between this water supply scheme and Example 1 is that four 400 cubic meters high-level pools are set in the parallel pilot tunnels of the service tunnel to replace the high-level pools in the high-level pool cavern in Example 1. Due to the long longitudinal slope of the tunnel and the service tunnel, the height difference between the highest point and the lowest point in the tunnel is more than 230 meters, which can make full use of the natural pressure generated by the longitudinal slope of the tunnel and place it at a suitable location in the parallel pilot tunnel of the tunnel. Set up a high-level pool. After calculation, the high-level pool of each sub-zone is set at a distance of 4000 meters from the low point of the sub-zone. The lower pipe gallery of the parallel pilot tunnel of the service tunnel is also arranged with drainage ditches and reservoirs at the low point, and submersible pressurized pumps are arranged in the reservoirs. , The water is sucked by the submersible pressurized pump, and water is supplied to the high-level pool in the service tunnel through the upper water pipeline that rises in the longitudinal direction of the service tunnel. The high-level pool is connected with the water supply pipeline in each subarea.

The advantage of this water supply scheme is that the entire water supply system is a constant high pressure gravity flow water supply scheme.

The disadvantage of this water supply scheme is that the water supply system is divided into four zones, among which the four high-level pools in the service tunnel supply water to zone 1, zone 2, zone 3, and zone 4. A total of 4000*2*4=32000 meters of DN200 pipelines are required. There are too many duplicate pipelines between partitions and the cost of the pipeline is higher, and the upper water pipeline from the high-level pool to the reservoir is too long and there are too many pipeline joints. There are too many faults and leaks, the pipeline is intricately laid, and the safety and reliability of water supply is very poor. When there is a power outage in the tunnel, the time required to transport water from the reservoir to the high-level pool by the water truck is more than 20 times longer than that in Example 1. When the fire is emergency, it is urgent to fight the fire. Extending the water transportation time will cause greater disaster losses. .

Example 4: A water supply scheme using a high-level pool on the inner side wall of the ventilation shaft

Compared with Example 1, the position of the high-level pool is all adjusted to the caverns that are expanded on the inner wall of the ventilation shaft 35. The advantage of this water supply system is that the cost of the system is lower, but the disadvantage is that there is no dedicated transportation channel and access road for maintenance. , In an emergency, water supply to the high-level pool. The inlet and outlet pipes of the high-level pool must be laid and fixed along the side wall of the ventilation shaft. Installation, maintenance and repair are inconvenient. The management personnel can only install the high-level pool through the side wall of the ventilation shaft. Up and down ladders with a height of 40 to 70 meters have a high risk factor, and it is difficult to set up power distribution, lighting, drainage and other facilities for high-level pools and caves.

After comparison and selection, the water supply system of Tianshan Tunnel is recommended to adopt Example 1.

The cross-sectional width of the transportation channel leading to the high-level pool is: 4.7m; the clearance height is: 6.2m;

The slope of the transportation channel leading to the high-level pool is not more than 30%;

The area of the high-level pool cavern is: 20m (length) × 12.5m (width);

The cross-sectional width of the high-level pool cavern is: 12.5m; the clearance height is 9.25m;

The size of the high-level pool and the drainage side ditch of the transportation channel is 15cm×15cm;

The height difference of the pavement at the two ends of the tunnel is greater than 198.89m, and the longitudinal slope of the tunnel is greater than 9.89km when the longitudinal slope of the tunnel is 0.836% to 2%.

Claims (4)

A fire-fighting water supply system for an ultra-long tunnel, comprising a tunnel and a service tunnel, the tunnel is parallel to the service tunnel, and is characterized in that the height difference of the pavement at both ends of the tunnel is greater than 198.89m, the longitudinal slope is not greater than 2%, and the longitudinal gradient is not greater than 2%. The slope length is greater than 9.89km, the temperature in the mountainous area outside the tunnel is below 0℃ all year round, and the thickness of frozen soil in the mountainous area is greater than 3 meters. On the lower pipe gallery road surface of the tunnel pavement and the drainage ditch lower than the lower pipe gallery road surface, the side wall of the tunnel is connected to the service tunnel through the inclined downward transportation channel, and the tunnel and the service tunnel are divided into several tunnels according to the ventilation shaft In each tunnel section, a 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 pool cavern through the transportation channel, and the ground of each high-level pool cavern is in each tunnel section The height difference between the high points of the tunnel on the ground is H, H=30-100m, each high-level pool is equipped with a high-level pool, and the transportation channel is equipped with a water pipeline connecting the high-level pool and the submersible pump arranged in the reservoir , Each high-level pool is connected to the water supply pipe network arranged in the corresponding tunnel section through the water supply pipeline to provide fire-fighting water. The fire-fighting water supply system for an ultra-long tunnel according to claim 1, wherein each tunnel section is provided with a water intake and a water supply port at each reservoir, which is convenient for water trucks to fetch water and water from the reservoir. Supply water to the reservoir. The fire-fighting water supply system for an ultra-long tunnel according to claim 1, wherein the gradient of the transportation channel is not more than 30%, which is convenient for the water truck to transport water to the high-level pool through the transportation channel. The fire-fighting water supply system for an ultra-long tunnel according to claim 1, wherein the longitudinal slope of the initial tunnel section located at the initial opening of the tunnel in the tunnel section is smaller than that of the remaining tunnel sections. Slope gradient, where the longitudinal slope gradient = tan(θ)×100%, θ is the longitudinal slope inclination angle, the initial tunnel section and the two water supply pipe networks in the adjacent tunnel section share the same connection to the adjacent tunnel section. The height difference between the ground of the high pool cavern where the high pool is located and the high point of the tunnel ground in the initial tunnel section H'=H+sin(θ)×L, where L is the length of the initial tunnel section .

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