Numbered G60 Hukun Expressway is one of the main trunk lines of the east-west horizontal line of the national highway network, is an important transportation artery connecting the western part of China to the eastern part of the country, with a total length of 2,730 kilometers, starting from Shanghai, passing through Hangzhou, Jinhua, Quzhou, Shangrao, Nanchang, Yichun, Pingxiang, Zhuzhou, Xiangtan, Shaoyang, Huaihua, Majiang, Guiyang, Anshun, Qujing, and ending in Kunming. Hukun Expressway is one of the most difficult highway projects in China, and the tunnel construction is rare in the country. Hukun Expressway passes through Qinglong County, Guizhou Province, with a total length of 50 kilometers in Qinglong, *** there are three tunnels, a short tunnel (Tongzilin Tunnel 245 meters), a medium tunnel (Wutong Tunnel 1,389 meters), and a long tunnel (Qinglong Tunnel 2,730 meters), (Note: according to the national highway industry standards for the division of tunnels, the extra-long tunnels ≥ 3,000 meters, 3,000 meters < long tunnels ≤ 1,000 meters, 1000 meters < medium tunnel ≤ 500 meters, short tunnel < 500 meters). Among them, Qinglong Tunnel is known to be the first longest highway tunnel in Qinglong area.
I. Overview of Qinglong Long Tunnel
(I) Design form. Qinglong long tunnel is located in Hukun high-speed 2044 kilometers, the use of four-lane closed highway design standards, for the upper and lower one-way traffic separation of the tunnel, a total length of 2,730 meters, the design speed of 80 kilometers / hour, one-way tunnel net width of 10.5 meters, net height of 5 meters.
(ii) fire fighting facilities. Tunnel set up a ring fire water supply network, up and down the line between the two inlet pipe, diameter 100 mm, water pressure by the high pool to maintain the network pressure of 0.3Mpa, water pressure is not enough by the fire pump to supplement. A hydrant box is set every 50 meters in the longitudinal direction of the tunnel, where water belt, water gun, water film-forming foam hose gun and water film-forming foam liquid are placed, and 2 sets of 4㎏ ABC-type dry powder fire extinguishers and 2 sets of water film-forming foam fire extinguishers are equipped. There are 2 aboveground fire hydrants in each of the two holes for fire extinguishing.
(3) Fire alarm facilities. The tunnel adopts the advanced automatic fire alarm system, and has the characteristics of high sensitivity and very low false alarm rate, the top of the tunnel is set up in the middle of the temperature-sensitive fiber optic detectors and monitoring probes, the monitoring room is equipped with temperature-sensitive fiber optic mainframe; set up every 50 meters of manual alarm buttons, every 200 meters set up a wired telephone. In case of fire, the trapped people in the tunnel can transmit the fire information to the fire alarm host in the monitoring room through the manual alarm button.
(4) Smoke control facilities. Three groups of 20 large jet fans are installed in the upward and downward tunnel for smoke exhaust and air supply, and the operation of the fans is linked with the fire monitoring system. In addition, the tunnel is also set up vertical smoke shafts, can also be used to travel (car) people cross-hole for natural smoke exhaust, basically meet the needs of fire fighting smoke exhaust.
(E) Safety evacuation facilities. For the characteristics of long tunnels, in order to facilitate the evacuation, the tunnel is equipped with emergency alarm telephone, but also set up an emergency broadcast. The tunnel is equipped with a lighting system and lighted traveling signs, and lighted evacuation signs are set up at the transverse opening to facilitate the rapid escape of trapped persons.
Second, the main features of highway fire accidents in very long tunnels
(a) the rapid spread of combustion. As the vehicle fire is the main danger of tunnel fire, caused by car fire and most of the electrical wiring short circuit, carburetor, loaded car pneumatic system and vehicles hit each other on fire. Each car has a fuel tank, they carry goods are combustible, once the fire, the fire source of high temperature, combustion spread fast. If the vehicle is carrying flammable and explosive substances and the following disaster vehicles, which will exacerbate the rapid development of combustion and fire.
(ii) smoke spread quickly, toxicity. Because the long tunnel is a long and narrow tubular space, when a fire occurs, the fire area will be filled with smoke, under the action of high temperature and hot air pressure, due to the limited smoke diffusion holes, the formation of most of the smoke accumulated in the limited space. Therefore, in the unit of three-dimensional space, the number of smoke is greater than the number of units of other building fires, and combustion of smoke produced by the toxicity of the space will make the oxygen content of a significant drop in the lack of oxygen is very easy to cause asphyxiation, or even death.
(3) rescue, evacuation difficulty. Long tunnels due to fewer entrances and exits, the internal passage is long and narrow, similar to be in a confined space, once the fire, smoke, high temperature, toxic smoke accumulation and other factors, rescue personnel to the scene, in the absence of direct observation to the part of the fire, the scope of the fire area, as well as the location of the trapped people, to evacuate the people, vehicles and materials is almost the same as a tiger's mouth to pull out the teeth.
(D) rapid disposal is difficult. Highway tunnels are generally far from the town fire department, the initial fire is easy to get out of control, the scene of the small room for maneuver, once the traffic fire accident, but also easy to cause traffic jams, which will directly lead to the obstruction of the fire trucks to quickly arrive at the scene. Fire trucks to the scene, has entered the tunnel in a vehicle and personnel evacuation tasks, fire water supply difficulties, once the loss of war, the fire is out of control, the tunnel will soon become a hellish labyrinth, so that the combatants deep inside the situation reconnaissance, evacuation of personnel, melee fire fighting and rapid disposal will become very difficult.
(E) accident disposal requirements. Highway tunnels due to the characteristics of the building construction, after a fire not only burning fiercely, explosion danger, high temperature, spreading fast, smoke and toxicity, low visibility, rescue and fire-fighting tasks "urgent, difficult and dangerous". Lack of attack road, little room for maneuver, close to the fire point is difficult, the direction of attack will be constrained by the external wind direction, the location of the fire and the burning range is difficult to grasp. If a chemical hazardous substances, toxic substances leakage and explosion, it is difficult to imagine what the consequences will be. Therefore, the difficult and dangerous fighting space, poor and narrow fighting environment and difficult to control the danger, more will be on the fire fighting tactics, self-protection and fire fighting equipment to put forward higher requirements.
Three, how to quickly and effectively carry out fire fighting and rescue operations in long tunnels a few thoughts (a) efforts to solve the tunnel air supply, smoke problem
(a) the importance of air supply, smoke
Tunnel set up ventilation and smoke exhaust facilities are determined by the tunnel's building structure. Compared with the ground building, the tunnel project structure is complex, confined environment, narrow passage, connected to the ground evacuation exit is less, the escape path is long. In case of fire, not only the fire spreads quickly, but also the accumulated high-temperature smoke is difficult to be removed naturally and spreads rapidly in the tunnel, which brings difficulties to the evacuation of people and fire-fighting rescue, and seriously threatens the life safety of the trapped people and rescue personnel. Due to the constraints and limitations of the tunnel structure, coupled with the impact of exhaust fumes from vehicles passing through the tunnel, the oxygen content in the air inside the tunnel is relatively low compared to the outside of the tunnel, and a large number of incomplete combustion products (e.g., CO) will be generated after a fire occurs inside the tunnel, forming a dense smoke that spreads rapidly. According to the test, the spread of smoke in the fire scene is more than 5 times the speed of fire, the fire in the tunnel should be regarded as an ignition point, due to the influence of the tunnel space, the spread of smoke is quite alarming, generally about 5 minutes after the fire began to spread, 15 minutes when the concentration is the largest, the spread of smoke makes the visibility reduced, and in the spread of smoke mixed with the CO is colorless, tasteless, and has a strong toxicity of the CO is a colorless, odorless and highly toxic flammable gas, which is extremely hazardous.
(ii) Utilization of fixed ventilation and smoke exhaust facilities
The ventilation and smoke exhaust system of the Qinglong Tunnel is a unified and independent system consisting of jet fans, silencers, air ducts, and air openings (the smoke exhaust system includes air booths), which exhausts smoke through the tunnel mouths and the shafts inside the tunnel. When the system is turned on, the jet fans in the tunnel send air in the same direction and the smoke flow is horizontal. In case of fire, it is bound to have some impact on the rescue tactical measures. The principle of smoke exhaust in the tunnel is to send air in the direction opposite to the direction of safe evacuation of passengers. This can not only prevent the smoke and people flow in the same direction, but also to the evacuation of escapees to send fresh air. Qinglong Tunnel adopts double-hole design, so in the event of a fire, the accident vehicle in front of the vehicle can be directly evacuated; the rear of the vehicle is blocked immediately after the stop, the passengers abandon the car to the opposite direction of escape. This determines the tunnel ventilation and smoke exhaust way: to the direction of traffic air supply, smoke exhaust at the other end.
(C) the use of mobile ventilation and smoke exhaust equipment
In the event of a fire, power outages or fixed facilities were destroyed, unable to meet the needs of ventilation and smoke exhaust in the tunnel, it is necessary to use mobile ventilation and smoke exhaust equipment. Through the calculation, the tunnel in normal conditions (calculated traffic speed 50km / h), CO allowable concentration of 200ppm, smoke allowable concentration of 7.5 × 10-3m-1; traffic jam (the minimum speed of 10km / h), the average allowable concentration of 300ppm CO, smoke allowable concentration of 9.0 × 10-3m-1; In addition to the tunnel wind speed should be satisfied with the diluted In addition, the wind speed in the tunnel should meet the wind speed required to dilute the odor in the air. Tunnel fire size according to the 20MW design, the use of longitudinal smoke exhaust, the requirements of the tunnel wind speed of 3m / s. Currently, the fire brigade is equipped with mobile smoke exhaust equipment, most of the electric smoke machine, water-driven smoke machine, etc., is to dispose of the tunnel fire accidents, a "sword".
(D) fast and effective implementation of tunnel rescue
Tunnel fire cases at home and abroad by the study found that many tunnel fire rescue errors are mainly concentrated in several areas. First, the rescue process of smoke exhaust air delivery is unfavorable, smoke filled caused by the evacuation of people difficult; second is the respiratory protection time limit, can not meet the rescue needs; third is the gas supply guarantee is unfavorable, affecting the continuity of the rescue work, delayed on-site rescue operations. Once the fire accident occurred in the highway tunnel, to quickly and effectively implement rescue operations, we must follow the relevant requirements to make the appropriate preparations.
1, ready for battle
(1) mobile smoke exhaust equipment in the fire scene
In the tunnel to ensure that the air supply and exhaust system under the premise of normal operation, as much as possible to mobilize the mobile air supply and exhaust equipment to arrive at the scene of the disaster disposal to increase the power of air supply and exhaust smoke. The use of high-power smoke machine in the tunnel at both ends of the entrance and exit respectively, the implementation of positive pressure air supply and negative pressure smoke exhaust, artificial control of the flow of smoke, to ensure that the escape channel without smoke infringement, to ensure that the rescue and the safety of rescued personnel.
(2) strengthen personal protection
In order to ensure that rescue personnel in the implementation of the fire rescue process of their own safety, into the tunnel interior personnel must strengthen personal protection, wear a good respirator. According to the different combat areas, according to the requirements of wearing ordinary fire fighting clothes, heat insulation clothing, fire clothing, etc.. Due to the tunnel disaster accident disposal process time is long, physical exertion, respirator should be able to provide a long time breathing protection of 4 hours of self-circulating oxygen respirator or 2 hours of dual-bottle air respirator.
(3) guarantee gas supply
Qinglong highway tunnel fire accident, should be timely mobilization of Zhongxian, Dianjiang and special detachment and other units of mobile gas supply vehicles, respectively, at the two entrances and exits to set up a mobile gas supply station, the organization of the cylinder transport team, to the forefront of the delivery of gas cylinders. On-site gas cylinders should be centrally placed in a cool place to avoid high temperature exposure to ensure that the gas supply is cool and comfortable.
(4) the formation of the tunnel war zone
The distance from the tunnel entrance and exit 5 minutes drive within the fire power to form a tunnel war zone, as a fire accident disposal of the tunnel Qinglong the first mobilized force. In order to ensure that the exhibitors fight quickly, organized, coordinated, to organize special training, the combat forces in accordance with the task is divided into: fire reconnaissance group, fire smoke group, communications lighting group, personnel rescue group, engineering demolition group, firefighting group, etc., each group of personnel were carrying professional equipment to carry out rescue operations.
2, standardized combat operations
(1) to strengthen the mobile gas supply security. Qinglong Tunnel is 2.7 kilometers long, the fire situation, to successfully rescue people from the tunnel, the rescue forces of the gas supply capacity is critical. After field tests, rescue personnel wearing ordinary air breathing apparatus to reach the most unfavorable point of the tunnel (i.e., the middle of the tunnel) the remaining air volume is difficult to meet the needs of the firefighters to start rescue operations. Therefore, personnel operating deep inside the tunnel must wear long-lasting breathing apparatuses (LLBAs) - either twin-cylinder air breathing apparatuses (SCBAs) or self-circulating oxygen breathing apparatuses (SCBAs), which can enable firefighters to reach the middle of the tunnel and work for at least 30 minutes. At the same time, as a team, carry a mobile air supply source as a backup air source for use by trapped personnel or rescuers in emergencies. It is not recommended that rescuers remove their own breathing apparatus for use by trapped personnel. Rescuers are organized in teams of 5 people each, carrying 1 mobile gas supply source.
(2) Ensure that escape routes are clear. Tunnel pedestrian (vehicle) crossings are trapped people escape both the life of the channel, but also can be used as firefighters within the attack channel. Rescue during the escape channel to maintain ventilation, good lighting, always in a positive pressure state, to prevent the intrusion of smoke. Because the channel is long and narrow, should be selected for the internal attack and rescue of people (car) crosswalk placed a fan to the channel to send air.
(3) stabilize the trapped people's emotions. After the fire in the tunnel, we should immediately use the tunnel broadcasting system to shout, inform the trapped people the correct escape method and the use of fixed fire fighting facilities, and use the recording system to play repeatedly. Deep inside the tunnel to start rescue operations firefighters, to use portable loudspeakers to shout, stabilize the trapped people emotionally, with the rescue operations to carry out.
(4) guide the evacuation of people and vehicles. Rescue personnel carrying work lights, strong lighting into the interior of the tunnel disaster site, along the evacuation channel laying luminous life-saving lighting line, placed self-storage lamps and adsorption of luminous guiding signs, etc., and the use of lighting trucks to introduce mobile lighting. At the same time, in the key areas that may cause loss of focus to send a person to stay, guiding the evacuation of people along the correct route to evacuate. At the same time, with the highway rescue team and traffic police cooperation, orderly evacuation of the tunnel blocked vehicles.
(5) rescue tunnel trapped people. To have the ability to act on the masses can be guided by the rescue personnel to evacuate along the escape channel; due to squeeze, touch caused by minor injuries to the trapped personnel can be assisted by rescuers to the escape channel, and then transferred to the medical emergency department after a simple treatment; has been in a coma or serious injuries can not be moved critically injured, you must use the torso to fix the stretcher transportation. In the implementation of personnel rescue process, rescue personnel should be rescued to provide the necessary protective equipment, such as the use of double mask air respirator accessory mask, mobile air supply source of double mask or carry a simple smoke mask.
(6) comprehensive search and demolition rescue. In order to ensure that all trapped people can be timely assistance, should adhere to the search and rescue through the whole process of fire fighting and rescue, thoroughly search every corner. Especially for the accident vehicles and blocked in the tunnel can not be evacuated in a timely manner of vehicles, to use infrared video camera, hydraulic breaking equipment group, two-wheeled anisotropic cutter and other special equipment, breaking the body, comprehensive search and rescue.
(C) vigorously solve the long tunnel fire rescue in the communication problem
Solution of the long tunnel fire rescue in the communication problem, to make full use of the tunnel internal communication facilities, the rapid formation of the fire scene communication network, to ensure that the wired, wireless communication smooth.
1, tunnel internal communication facilities
Tunnel internal communication facilities are divided into specialized communication facilities and public communication facilities. Among them, the dedicated communication facilities are divided into: tunnel scheduling communication system, traffic signal control system, automatic fire alarm system, video monitoring system and broadcasting system; public communication facilities are: public wired telephone communication system, radio communication system. With the existing tunnel scheduling network (wired) and public mobile communication network (wireless) can be used as a means of communication command for the initial fire rescue, but can not rely solely on the above system, in the case of fire, the fire brigade must also be equipped with underground mobile communication equipment, can be in the case of the failure of the above facilities to continue to set up a communication command network on the scene.
2, tunnel fire disaster site communication network steps
(1) the establishment of a squadron of communication command. The competent squadron to the scene, first of all should use the tunnel fixed communication facilities (such as tunnel scheduling communications network, cell phones, tunnel PA broadcast, etc.) to establish underground and above ground communication links, in the case of fixed communication facilities can not be used, the use of wireless communication extension equipment to establish effective communication, rescue and disposal operations.
(2) Establishment of on-site communication command center. The use of vehicle-mounted equipment to establish on-site communication command center, open the scene command wireless communication network, wired communication network, computer communication network, satellite image transmission and broadcasting, complete the fire rescue command and local government, public security, emergency, highway management center and other rescue departments to establish and maintain wired and wireless communication links, through satellite transmission equipment to the 119 command center to transmit images of the scene, accept and Communicate the orders of the higher command and 119 command center.
The above is collected and organized by Zhongda Consulting
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