Zhang Jiankui: Director of Editorial Department of Times Trend Magazine of People's Daily.
Native place: Shandong
Major: journalism, law; Graduate institutions: Beijing Broadcasting Institute, Central Party School.
Education: Bachelor's degree
Date of birth: 1982 65438+ 10/0.
Touch wind volcano
● The highest tunnel in the world, with an altitude of 4905 meters and a total length of 1 338 meters, is extremely cold, low pressure, lack of oxygen, snowstorm, lightning and sandstorm, which is daunting.
● Soil-bearing ice layer, shallow buried stratum, hot melt geology and rich frozen soil are all "world-class" problems one after another. At 2 pm on July 24, our reporter Zhang Jiankui bid farewell to the caravan and continued to drive south. An hour later, Master Huang, who was driving, told us that he had entered the no-man's land of the wind and volcano. At 3: 50, we arrived at the Qinghai-Tibet Railway Headquarters in China Railway 20th Bureau, a simple courtyard built by the 20th Bureau. The leaders here all went to the construction site, and a comrade in the office received us.
In the late July season, in most parts of the mainland, it can reach above 30℃ during the day, but the houses here still have heating. Comrades in the office told us that the annual average temperature here is below -7℃, and now the temperature is-4-5 degrees at night. Just as we were taking oxygen and listening to the comrades in the office, the weather outside suddenly changed. Looking through the window, the wind and sand burst, the flying clouds galloped, accompanied by thunder and lightning.
"The rain here seems to be coming soon."
"Now there are 6 or 7 strong winds outside, mostly thunder and no rain, and it will snow!"
"Hey, it's snowing? Isn't this a timely rescue? "
"Yes, snow and hail are the most common here in June and July, but it won't take long."
Sure enough, after a while, the wind outside stopped and it didn't rain today.
The seventh bid section of Qinghai-Tibet Railway was built by the 20th Bureau, with a total length of 36.02 kilometers. It is located in the "no man's land" of Hoh Xil, with an average elevation of 4,700m m. It is extremely cold and anoxic, with harsh natural environment, fragile ecological environment and extremely difficult construction conditions. This section is mostly permafrost region, with thick permafrost layer, and the lowest temperature in winter reaches -40℃.
"In In the snow in June, in the ice in July, the four seasons can't be distinguished" is a true portrayal of the climate conditions here. The oxygen content in the air is less than 50%, and the partial pressure of oxygen is only 10.87 kPa, which is lower than the human survival limit value 1 1 kPa. It is a real "life forbidden zone".
It is under such conditions that the Iron Man of the 20th Bureau overcame the international technical problems and created the miracle of railway construction in the world, that is, the tunnel with the highest altitude in the world-the Wind Volcano Tunnel.
At 5: 20 pm, under the leadership of the comrades of the 20 th Bureau, we decided to go to the Fenghuoshan Tunnel to experience it on the spot.
Along the way, the story about the "Wind Volcano Tunnel" drew us back to the deadly battle that lasted for 365 days.
200 1 10 18, the wind volcano under the blue sky and white clouds looks particularly charming. At the construction site of Fenghuoshan Tunnel, colorful flags were flying, and 200 employees were dressed in orange youth commando uniforms, and they were busy on the construction site ... dozens of large-scale construction machinery were waiting. A fierce battle, a war of science and technology, is imminent. 165438+ at 0: 30 in the morning, with the command, crisp explosions came and went, and white smoke floated into the blue sky.
After a burst of blasting, the scene in front of us stunned the people present: these blasted dregs were almost crystal clear ice cubes, shining with cold light under the sunlight. This is what tunnel experts at home and abroad call the "soil-bearing ice layer" of disaster geology, and the soil content in the ice is less than 20%. Wind volcano, this Millennium iceberg finally revealed its ferocious face. This kind of geology has always been considered as a "forbidden zone" for tunnel construction. In the face of this world-class construction problem, the scientific and technological research team headed by the chief engineer and commander of the 20 th Bureau has all devoted themselves to the tense support work. The commandos quickly rushed to the tunnel face, the shotcrete workers picked up the concrete nozzles, and the anchor workers picked up the air guns and hammers ... Everything was going on nervously and orderly. After more than four hours of intense fighting, the support construction was fully completed and the first round of initial victory was achieved. Subsequently, after several rounds of excavation and support construction, a set of experience of smooth blasting of frozen rock and bolting and shotcreting support of tunnel body was explored, the construction scheme and scheme were optimized, and the construction scheme of "short footage, quick closure, strict temperature control and strong support" was determined. This scheme worked quickly in the construction, and finally broke through the problem of soil-bearing ice layer in one fell swoop. At the same time, it also breaks a new path for the follow-up construction.
Wind volcanoes that no one has conquered will not bow easily. The newly supported 150 square meter thermal insulation greenhouse was torn to pieces by strong wind overnight; In the newly-built generator room, the iron tile on the roof disappeared the next morning; Just now, the sky was clear in Wan Li, and in a blink of an eye, dark clouds were overwhelming, and hail the size of peanuts hit ... Strong winds, snowstorms and lack of oxygen launched a sustained attack on construction workers. With the continuous extension of Fenghuoshan tunnel, the construction is becoming more and more difficult. The air in the cave is getting thinner and thinner, and the lack of oxygen makes everyone feel chest tightness, shortness of breath, headache, soft legs and purple lips. In the past, only two people were needed to operate each typhoon gun, but now four people are needed to control it. The shift used to be four hours, but now it must be changed every two hours. Everyone knows that if you work in a windy volcano, you will overdraw your life and even face the danger of death.
Wind and volcano always affect the hearts of units and leaders at all levels. Sun Yongfu, deputy head of the National Leading Group for the Construction of Qinghai-Tibet Railway and vice minister of the Ministry of Railways, visited the Fenghuoshan Tunnel many times and encouraged the 20th Bureau to "rely on science and technology to build the highest tunnel in the world". The People's Government of Xizang Autonomous Region, Qinghai Province sent a condolence group and sent condolences; The leaders of China Railway Construction also visited the workers of Fengvolcano successively.
200 1, 1 1 year1October, the 20th Bureau, in conjunction with relevant researchers from University of Science and Technology Beijing, developed and built a large-scale high-altitude oxygen station in the Fenghuoshan tunnel, installed an oxygen pipeline, and sent oxygen directly to the tunnel face, thus realizing the diffusion and oxygen supply of the whole tunnel. At the same time, an oxygen bar car is installed in the tunnel, so employees can take full oxygen in the oxygen bar car to relieve fatigue.
Overcome the problem of lack of oxygen, greatly improve the construction environment, and effectively protect the physical and mental health of employees. With oxygen, everyone has more confidence and energy to conquer the wind volcano.
If the construction of the Fenghuo tunnel is difficult, it is difficult to be in cold and lack of oxygen, and it is difficult to be in plateau frozen soil, then the shallow buried section of 296 meters long is enough to make people tremble with fear.
After the tunnel entrance is excavated for 222 meters, it will enter the shallow buried section for construction. Among them, there is more than 60 meters of overburden within 8 meters, and the geology of this section is mudstone fully weathered layer, and the dome is full of ice and frozen soil within 2.5 meters.
At that time, the surrounding rock temperature was between 2 and 5 degrees Celsius. At this time, the cracked ice began to melt, forming a melting circle. The melted mud crackled on the helmet, and everyone's mood was extremely heavy. If the melting circle is further expanded and the support can't keep up, it is very likely to cause landslides. The real test of life and death began. Ren Shaoqiang, chief engineer of the headquarters, led engineers and technicians to continuously detect the temperature in the cave and monitor the surrounding rock, adjust the temperature in the cave at any time and observe the temperature changes; Commander Kuang led the research team to study how to safely pass the "shallow buried section" construction scheme. After three days and three nights of experimental temperature change measurement and control, the research group obtained first-hand information and basically grasped the temperature changes of various parts in the cave at different times. Based on this, the construction scheme of "weak blasting, short footage, strict temperature control, strong support and reserved core soil" was formulated. After nearly 60 days of experimental construction, the "shallow buried section" finally passed safely and the construction progress was driven.
In the process of construction, technicians and workers found that both saturated frozen soil, primitive glaciers and cracked ice have the property of hot melting. Frozen soil is the main factor affecting the safety of tunnel construction, but temperature plays a key role and is the fuse to detonate frozen soil.
In order to eliminate the obstacle of "temperature", the research group launched a tenacious contest with "temperature".
Through continuous practice and exploration, we all realize that the key to control the temperature is to control the temperature in the process of excavation, support, formwork entry, maintenance and mixing. At the beginning, people used stoves to heat caves, which not only caused the temperature to rise slowly, but also caused air pollution in caves, affecting the health of employees. Later, the heater was used to raise the temperature, but the effect was still not ideal. Can air conditioning control the temperature in the tunnel? Someone put forward this bold idea, but at present there is no air conditioner with such high power in China. What shall we do? The 20th Bureau and Shijiazhuang Railway Institute jointly developed a special air-conditioning ventilator for large tunnels after consulting relevant experts and demonstrating in many ways. When driving, use the air-conditioning ventilator to deliver the required cold air to the tunnel tunnel face, and ensure that the tunnel face temperature is controlled between plus and minus 5 degrees Celsius to meet the driving needs. When supporting and lining, the temperature should not be too high or too low to the supporting face to ensure the appropriate temperature of supporting and lining. In order to solve the temperature of concrete entering the mold, two large steam boilers were installed at the entrance of the cave for 24-hour central heating, and two thermal insulation greenhouses were built. The mixing station, sand and gravel, and construction water are all put into the heat preservation shed, so that the temperature of the mixing station is always above 65438 00 degrees Celsius, and the temperature of concrete entering the mold is not lower than 5 degrees Celsius.
After controlling the temperature of concrete entering the mold, new problems appeared again. This is the control of concrete curing temperature. In this regard, engineers and workers have not paid less attention. In order to ensure the curing temperature after lining, after repeated practice, the heating pipe is finally used to transport the required heat and temperature, and the steam curing method is adopted to solve the curing problem of concrete after lining. By adopting different methods, various temperature problems in construction are solved.
It stands to reason that only by solving the problem of lack of oxygen in the construction and controlling the construction temperature in the tunnel can the tunnel construction proceed smoothly. However, the "rich frozen soil" reappeared and the construction was blocked again.
The so-called "rich frozen soil" refers to the geology in which frozen soil contains more ice bodies. During the construction, it is found that the main characteristics of "rich frozen soil" are similar to those of "soil-bearing ice layer" and are also very sensitive to temperature. In order to overcome the technical problem of "rich frozen soil" as soon as possible, Ren Shaoqiang, the chief engineer, led the scientific research team to challenge "rich frozen soil" again. Through the experiment, we found that the main technical difficulty of "enriching frozen soil" lies in how to improve the blasting method and how to quickly improve the strength of concrete support. In order to solve these problems, the research group decided to adjust the working procedure and adopt the "tube explosion method". After blasting, cold air is quickly transported to the tunnel face to prevent the "rich frozen soil" from being melted by heat; At the same time, the "super-advanced" support is implemented to ensure the stability of surrounding rock. Careful organization and scientific construction finally subdued the disastrous geology of "rich frozen soil".
September, 2002 12, tunnel excavation broke through the 1000 meter mark, and the double-hole entrance achieved a new record of more than 100 meters.
Everyone has suffered a lot for the tunnel in Huofeng Mountain. Due to the severe hypoxia in Huofeng Mountain, 65,438+0,000% workers have altitude sickness in different degrees, so they can't eat or sleep. Everyone's weight dropped by 1.2 kg on average, reaching more than 30 kg.
History will always remember this day, June 65438 +654381October+September 2002. On this day, leaders and experts from the Ministry of Railways, Xizang Autonomous Region and Qinghai provinces, as well as dozens of news media, such as Xinhua News Agency and CCTV, all focused on the abundant volcano. As Lu Chunfang, the commander-in-chief of Qinghai-Tibet Railway Construction, started the last button, firecrackers, applause and cheers turned the volcano into a sea of joy in an instant.
At 5: 50, we arrived at the Fenghuoshan Tunnel. The word "wind volcano tunnel" at the top of the hole is very eye-catching. It's a little quiet here, because there are no rumbling guns and roaring machinery. A long track extends into the deep tunnel, and there are fading lights in the depth. By the light, you can see someone working on the cave wall, and from time to time, a bucket car full of cement slowly slides along the track to the mouth of the cave.
The comrade who led us said that there was little oxygen in it and we couldn't go in. Just leave a souvenir at the tunnel entrance!
Adapting the fifth grade text
According to the original work, Building a Railway to Lhasa was selected as a fifth-grade Chinese textbook.
Build a railway to Lhasa!
200 1 10 18, the wind volcano under the blue sky and white clouds, wrapped in silver, is particularly enchanting. Colorful flags were flying on the construction site, and hundreds of young commandos in orange uniforms and dozens of large construction machinery were waiting.
With an order, bursts of blasting sound resounded through the snowy plateau, and the excavation of the Fenghuo tunnel was completed. A long "Iron Dragon" starts from Golmud, an industrial new city deep in the Qaidam Basin, crosses the towering Kunlun Mountain, will pass through here, cross the Qinghai-Tibet Plateau, the "roof of the world", and reach the snowy holy city Lhasa. This is the Qinghai-Tibet Railway, the landmark project of the western development, and this is the Qinghai-Tibet Railway that benefits the broad masses of the people.
Wind-volcano tunnel has to pass through permafrost regions, and there are all kinds of complicated frozen soil layers in front, so the construction is extremely difficult. Blasting again and again, what is blown out is not stone, but hard ice slag. No wonder some western media predicted that it is impossible for China people to dig tunnels under such bad geological conditions!
Building a railway to Lhasa is really not a simple matter. What is being built is a plateau frozen soil railway with the highest altitude and the longest route in the world. The key to the construction of Fenghuoshan tunnel is temperature control. The technicians directed the commandos to spray concrete on the wall of the tunnel that had just been dug. Because the temperature is too low, concrete can't set. They brought a heater to heat the tunnel, and the ice rock on the tunnel wall melted when heated, causing the tunnel wall to collapse and slide. Wind volcano, this 10,000-year-old iceberg has revealed its ferocious face, giving the road-building army a duel!
However, all this is not difficult for our road-building army. Scientific and technical personnel observed day and night in the tunnel and found the temperature change law of ice rock. After repeated observation, analysis and experiments, they finally found the best temperature for shotcrete and subdued the frozen soil that had been raging for a while.
Build a railway to Lhasa! The morale of the road-building army is high, and the tunnel is extending bit by bit.
Bad weather and extreme lack of oxygen in turn attacked the team. There are often strong winds around the wind volcano. The newly-built 150 square meter thermal insulation greenhouse was torn to pieces by the strong wind overnight. In the newly-built generator room, the iron tile on the roof is missing. The sky was clear in Wan Li just now. All of a sudden, dark clouds were all over the place, and large and small hailstones swept down. The wind volcano is 4905 meters above sea level, and the oxygen content in the air here is less than half that of the plain. The deeper the tunnel is dug, the thinner the air in the tunnel is. Although they are ready for lack of oxygen, the situation in the construction still makes them unexpected. The oxygen provided by the oxygen cylinders on the workers' backs is only a drop in the bucket. All commandos have chest tightness, shortness of breath, headache and leg pain. The wind gun used by two people can only be answered by four people now. Labor efficiency drops rapidly. The life of the road-building army is facing a serious threat.
The lights at headquarters are on all night. Can you build a large oxygen station? Headquarters and University of Science and Technology Beijing formed a joint research group to overcome this new problem. Scientific and technological personnel forget to eat and sleep, experiment day and night and tackle key problems. After more than 200 failures, the world's first large plateau oxygen station was built! Sufficient oxygen is continuously fed into the tunnel along the long pipeline. Wind volcano, this huge stumbling block lowered its proud head again and again!
Build a railway to Lhasa! Build a railway to Lhasa! Commandos and technicians shouted the same wish over and over again. On June, 2002, 65438+1October, 65438+1October, 09, 1338-meter-long Huo Feng Tunnel was finally successfully completed!
The "iron dragon" of the Qinghai-Tibet Railway is constantly moving forward, and Lhasa is in sight. ...