Author: Tang Kejun, Li Genxue

"Don't shoot. Seeing the reporter pointing the camera at him, Jiang Dong gently spit out two words and held back tears.

"I haven't regretted it, it's a little harder, but everyone is here, and I feel that there is no hurdle that I can't pass. Speaking of this, Jiang Dong turned his head to look out the door, tears sliding down his face.

Outside the gate, the view is blocked by overlapping mountains, which is the famous Hengduan Mountain Range.

The tunnel site is located in the middle of the Hengduan Mountains, with the Lancang River in the lower left corner. Photo by Tang Kejun

In the mountains, on the bank of the Lancang River, a 14.5-kilometer-long railway tunnel, Jiang Dong and his brothers from the No. 4 Company of China Railway First Bureau have been fighting hard for 9 years, and the main tunnel is still more than 4 kilometers away, and the flat guide is still more than 3 kilometers away to break through.

They have an agreement, when the face of the palm is through, everyone will not see each other.

26 months, 156 meters

The Lancang River rushes south in the Hengduan Mountains. Photo by Tang Kejun

Located in the southeast of the Qinghai-Tibet Plateau, the Hengduan Mountains are the most complex and rugged mountain system in the world. Here, the mountain changed the convention from west to east, and the brushes traversed from north to south, blocking the traffic in the east-west direction, so it was named "Hengduan Mountain".

Historically, every path that humanity has blazed a trail here has paid a heavy price. The Yunnan-Burma Highway built in 1938 is known as the "Blood Road", and almost every foot of the road is congealed with blood during the construction process, and when the Chengdu-Kunming Railway was built half a century ago, more than 1,000 railway soldiers were buried in the green mountains.

"Twenty years ago, such a project would have been unthinkable. You Hongsheng, secretary of the Discipline Inspection Commission of the Fourth Company of China Railway First Bureau, said that the Chengdu-Kunming Railway actually only passed from the edge of the Hengduan Mountain, and the 330-kilometer-long Dalui Railway was the first railway to cross the Hengduan Mountains.

There are more than 40 tunnels in the Dalui Railway, of which the 14.5-kilometer-long Dazhushan Tunnel has not been broken through for 9 years since the start of construction in 2008, refreshing the history of the railway, and is known as the most difficult tunnel to excavate in China.

Workers spray concrete in the water.

On the tunnel excavation face - the tunnel face, water gushing and mud bursting are the situations that construction personnel are most afraid of. There are many tunnels in China that are difficult to excavate, and mud and water gushing are not uncommon. In the Dazhushan Tunnel, disasters have become a daily routine. 90% of the time, people are battling the sudden gushing of water and mud.

The entrance of the Dazhushan Tunnel is a mud gushing water on the face of the Swallow's Nest Fault, and a large amount of mud and sand mixed with solitary stones instantly paved the tunnel.

Cheng Rui, who was in charge of the construction of the tunnel entrance, once photographed a mud burst at close range: a small hole appeared on the face of the tunnel, and a mixture of mud, sand, and gravel flowed out, and a large stone blocked the hole, but it soon also fell, and the hole became bigger and bigger. In the end, the mudslide filled the tunnel in front of them for dozens of meters, burying the fruits of their months of hard work.

The entrance of the Dazhushan Tunnel is a sudden mud gushing from the swallow's nest fault, and the entrance of the cave instantly becomes an ocean.

"This time the water gushing, from September last year to the present, the tunnel has only advanced about 20 meters, nearly 3,000 cubic meters of water per hour, it is impossible to construct at all, there is no footage in the tunnel, it is useless to say anything. Cheng Rui said as he spoke, and his eyes turned red.

Fortunately, no casualties have been reported since the start of construction in 2008.

But that doesn't mean there is no cost. This time it's time at the price.

Erection workers brave the water in the tunnel to install the steel frame.

"The main tunnel of the Dazhushan Tunnel and the Pingdao have to cross a total of 12 faults, and 10 have been passed so far, and the most difficult one before is the swallow's nest fault, which was constructed in shifts for 24 hours, and only 156 meters have been excavated in 26 months. Jiang Dong, project manager of Dalui Railway of China Railway First Bureau, said that more than 500 experts have come to consult, and no faster way has been found.

"When the project was approved, I didn't realize the complexity of the geology. Zeng Jin, deputy commander of the Dalui Railway Headquarters of the Yunnan Company of Yunnan-Guizhou Railway, said, "The whole line was originally planned to be completed in 2014, but now it seems that it will be completed in 2021." ”

The decisive battle is "deep water" and "hot"

The water gushing out of the entrance of the Dazhushan Tunnel cascades down the mountain like a waterfall. Photo by Shi Feilong

On the cliff on the west bank of the Lancang River, a waterfall rushes straight down, and the source is the Dazhushan Tunnel.

Turbulent water in the tunnel. Photo by Tang Kejun

Just a few meters after entering the tunnel, the reporter's rain boots were filled with water and his pants were completely soaked.

Life jacket inside the tunnel. Photo by Tang Kejun

On the wall of the cave near the face of the tunnel, the red life jacket and swimming ring stand out.

23-year-old Wang Yufu. Photo by Shi Feilong

The reporter is interviewing Wang Yufu.

On the left side of the face, 23-year-old Wang Yufu wears a raincoat and life jacket to drill a hole in the rock wall to drain water. Columns of water shot out of the borehole, and he and his co-workers hunched their backs and stuffed the drill into it, covering their bodies in the water.

Workers install drill bits against the current. Photo by Tang Kejun

Workers brave the huge water pressure and struggle to carry out the construction. Photo by Shi Feilong

The workers were soaking wet. Photo by Tang Kejun

There was a lot of water in the tunnel. Photo by Tang Kejun

A technician inspects the drainage. Photo by Tang Kejun

"The geology of the Lancang fault zone is the most troublesome, and we don't know much about it. He Wanyang, executive deputy manager of the Dalui Railway Project of the Second Institute of China Railway, said, "The water inflow of the Dazhushan Tunnel has reached 150 million cubic meters, which can fill 15 West Lakes. Where does all this water come from? It's hard to tell exactly. ”

Workers sit on ice cubes to rest. Photo by Tang Kejun

At the other end of the "water depth" is "fiery". In the direction of the tunnel exit, Fu Yiping and the workers could only work in pants, pulling up the water pipe and watering it from head to toe every ten minutes. When the heat is unbearable, I go to the construction site and sit on the large ice cubes I bought from outside for a while. Even so, a class can only last two hours.

Ice cubes weighing up to one ton melt away in two to three hours after being placed in the tunnel.

Chen Zhiqiang, who is in charge of the construction of the tunnel exit, told reporters that the high ground temperature and the single-head excavation of more than 7,100 meters caused the difficulty of ventilation, so that the temperature of the tunnel face reached nearly 40 degrees Celsius.

At the "hot" end, there will also be water. And because the tunnel face in the exit direction is lower than the hole entrance, the water cannot flow out by itself, and can only be drained against the slope. The project department built 5 pumping stations and 40 large pumps to relay the water from the tunnel to the outside of the tunnel.

After the excavation of the entrance of the Dazhushan Tunnel, the surrounding rock was unstable, and a large amount of surrounding rock was stripped and fell, and the construction results of many days were destroyed.

"Depth" and "heat" are just two of the many puzzles. The Dazhushan Tunnel passes through more than 30 kinds of surrounding rock, and there may be a variety of geologies within a few meters. "There may be a river hidden in the rock, it may be a mudslide ditch, it may be gas, radiation, weak surrounding rock, and the slightest carelessness can be a disaster. Liu Xinhua, chief engineer of the project, said.

"If the surrounding rock is good and I can dig quickly, I feel like winning the lottery. Cheng Rui said, "If the surrounding rock is poor, you can't take a step forward for several months, and you will be in a bad mood and hopeless." ”

"On the project, everyone has a word of blessing to each other: I wish you a good rock!" said Zhang Bin, deputy secretary of the party branch of the project department.

The promise is not broken

Technicians discuss the construction plan in front of the tunnel. Photo by Shi Feilong

"It's been 9 years, some people have graduated from college and been assigned to us, in love, married, and have given birth to two children, but the position has not changed much, if it was placed in other projects, it would have been a middle-level cadre or even deputy manager and manager. Jiang Dong said, "Of course, there are many people left." But those who remain are ready to hold out to the end. ”

Wu Hao, who was born in 1992, is one of them. "Come home with me, our family doesn't lack this salary!" Last year, Wu Hao's father traveled from Weinan, Shaanxi Province to Baoshan, Yunnan, where the project is located.

Asked why he didn't leave, everyone's eyes turned to Jiang Dong, "Brother Jiang treats us as brothers, and he is here with us." ”

Jiang Dong, project manager of Dalui Railway of China Railway First Bureau. Photo by Shi Feilong

"Actually, it's not me. Jiang Dong paused and said, "How can you leave without finishing a thing, if you leave halfway, how can you have the face to tell others or your own children in the future." ”

Jiang Dong said: "We have already made an appointment, and when the palm is connected, everyone will see you and leave!"

As of May 31, 10,033 meters of the Dazhushan Tunnel has been completed, and the level guide excavation has exceeded 11,000 meters, and it is passing through the last fault called "one well water". According to this progress, the Dalui Railway is expected to be put into operation in 2021.

In Baoshan City, Yunnan Province, part of the bridge project of Dalui Railway has been nearly completed. Photo by Tang Kejun

At that time, the train will only take 7 minutes to pass through the 14.5-kilometer Dazhushan Tunnel, but few people know that Jiang Dong and his brother have paid 13 years of youth for the smooth passage of more than 7 minutes.

News Links

Dalui Railway

The Dali-Ruili Railway starts from Dali Station in the east to Ruili, a border city of China and Myanmar in the west. After the railway starts from Dali, it goes down along the right bank of the Xi'er River, crosses the Yangbi River, the Yinjiang River and the Lancang River, passes through the Dazhu Mountain to Baoshan City, and then passes through the Nujiang River and Gaoligong Mountain, and finally arrives at Ruili, with a total length of 330 kilometers. The Dalui Railway is one of the new development projects in the western region, and is also an important part of the China-Myanmar International Railway Corridor, which is one of the inbound and outbound corridors in southwest China.

After the completion of the Dalui Railway, it will reshape the glory of the ancient Southern Silk Road, further highlight the role of Yunnan as a bridge and link for opening up to Southeast Asia and South Asia, and have far-reaching significance for promoting the economic and social development of the regions along the line, improving the level of Yunnan's opening up to the outside world, and promoting exchanges and cooperation between China and Southeast Asian and South Asian countries.

Big Pillar Hill Tunnel

The Dazhushan Tunnel is the highest risk tunnel on the entire Dalui Railway. It is designed as a single-track railway tunnel, with a total length of 14,484 meters, set up with "two horizontal and one flat", and the maximum buried depth of the tunnel is 995 meters. The longitudinal slope in the tunnel is designed as a "human" slope, except for the exit section of 2750 meters is 3‰ uphill, and the other maximum longitudinal slope is 23.5‰. Tunnel construction can only be excavated from the entrance and exit of the single head, without auxiliary construction conditions such as vertical shafts and inclined shafts, and the maximum single-head reverse slope excavation is 8400 meters. The construction of the main tunnel and the flat guide is limited by the site conditions of the tunnel entrance, and the construction interference is greater. The flat guide assists the construction of the main tunnel, and its multi-face construction has great interference and difficulty in long-distance ventilation, transportation, water supply, power supply, etc., and the construction coordination and management ability is extremely high.

The engineering geology and hydrogeological conditions of Dazhushan Tunnel are complex, with the characteristics of "three highs and four active", and there are 6 fault fracture zones (with a total length of 1200 meters, including 640 meters of Shuizhai fault), karst and karst water, dark river, karst cave and other karst forms, rockburst caused by high geostress and large deformation of soft rock, radioactivity (1600 meters), high geothermal (39 °C) and other undesirable geology. During the construction, it is easy to encounter geological disasters such as water inrush, mud inrush and instability of surrounding rock, especially in the strong karst water and some fault zones (especially the normal faults with mud inclusion and fracture zones), which are prone to produce large-scale water inrush and mud inrush sections (3210 meters, the maximum water inflow is 120,000 meters 3/d). In the tunnel body through the surrounding rock at all levels, the rock quality is harder, brittle, especially in the stress accumulation zone of hard rock, the greater stress is gathered, and the rockburst phenomenon is easy to occur in the construction, and at the same time, the tunnel passes through the coal measure stratum of 1.27 kilometers, containing gas gas.

During the construction of the entrance of the Dazhushan Tunnel, it has successfully passed through the Flat Bird's Nest Fault, the Zhengdong Swallow's Nest Fault and the Flat Channel Shuizhai Fault, among which the construction of the Flat Bird's Nest Fault is the most difficult and time-consuming.