Dayaoshan tunnel was upgraded and reopened, and the "natural danger" was broken!

"All of them are steep and evil roads that are hard to follow, sometimes they are surrounded by cliffs, sometimes they pass by single trees." Fei Xiaotong regarded Dayaoshan as a "natural danger" in the Guihang correspondence. At 10:17 on October 23, after 210 minutes of tight closed interlocking construction by more than 300 technicians, the Dayaoshan tunnel, with a total length of 14.295 kilometers, was listed as the world's tenth largest double line railway tunnel, and was successfully opened to traffic, marking that the technical problems of upgrading and upgrading the double line electrical equipment were overcome, and the three-year-old automatic blocking and interlocking equipment transformation project of Guangping section of Beijing Guangzhou railway will be opened.
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The project starts from the border of Hunan and Guangdong Province in the north, and ends at Shaoguan direct station in the south. The whole line is 103.10km long, involving the transformation of computer interlocking equipment and automatic block equipment of 9 stations, including Pingshi station, luojiadu station, Tuling station, Zhangtan station, Lechang station, Ankou station, Huanggang station, Shaoguan direct line station, and the associated works of communication, power, housing construction, etc.

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Dayaoshan tunnel was first built in the 1980s. More than 4000 workers spent five years to construct it. It was opened on May 6, 1987 and was the longest railway tunnel in China at that time. With the opening of Dayaoshan tunnel, the railway distance has been shortened by nearly 15 kilometers, and the train speed has been increased from 50 kilometers per hour to more than 100 kilometers per hour, strengthening the communication between Lingnan area and the mainland. The geological structure of Dayaoshan is complex, the rock weathering is serious, there are many faults, and the water inflow is large. There are many pipelines in the tunnel, the space is narrow and the environment is bad. "At a glance, the scalp is numb and the silk holes are not so complicated." This is the most real feeling of the construction personnel for Dayaoshan tunnel.

In April 2016, the third company of China Railway Electrification Bureau, known as the "Central Plains Iron Army", sent "main force" to the Wushuihe Bank of Lechang City to carry out the self closing transformation of the Guangping section of Beijing Guangzhou railway. A tough battle for the transformation of the railway began quietly. Dayaoshan tunnel is an important and difficult project in the reconstruction of Guangping section. The 14.29 km tunnel includes 22 signal points, 66 track sections of equipment replacement and 172 km of optical and cable laying. The dust is flying in the tunnel, the visibility is low, the construction is difficult, and the safety risk is high.

"key point construction" is the difficulty of the construction of the existing line, which requires not only "short, smooth and fast", but also "stable and accurate", and has high risk. The Beijing Guangzhou railway is the main railway artery running through the north and south of China. On average, there is a train passing by in 3-5 minutes, with only 120 minutes of "skylight point" each time. For this reason, the project department sets up a site construction guidance group to formulate construction plans one by one, and carry out fixed-point positioning and precise measurement for each equipment to provide accurate technical data for construction.
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The construction site is located in the mountainous area at the junction of Guangzhou and Hunan Province. It is hot and rainy, with tunnels and bridges densely covered, and there are many potential safety hazards in the construction. The project department shall establish a safety and quality hidden danger screening system to check and rectify the safety and quality hidden danger one by one, to ensure the safety and orderly progress of reconstruction construction.

The main tunnel is 14 kilometers long, the auxiliary tunnel is only 7 kilometers long, and the daily construction "skylight point" is only two hours. In order to ensure the construction efficiency, the construction preparation time is up to five or six hours. After the skylight point is given, the auxiliary tunnel can enter the main tunnel. "There is a lot of dust and noise in the cave. The smell of coal truck and oil tank truck is disgusting. "Coming out of the tunnel, everyone was covered with dust, leaving two rows of teeth white. "The tunnel is long, and the 'skylight point' is limited every day. It takes time and effort to transport the cable to the tunnel before laying the cable; the tunnel space is limited, and the access of all construction materials and tools is basically carried by manpower, with very low efficiency; in the later stage, the stability of the box needs to make a head, strip the cable, wiring, and looping, and a complete box needs at least three 'skylight points', the personnel of the operation team While ensuring physical strength, they also have to bear great mental pressure. " Technical personnel of the third company of China Railway Electrification Bureau said.

The cable in signal construction is generally laid by excavation of cable trench. The original design plan is to replace the existing cable trench, first lay and open the cable, then clean the old cable in the existing trench, and finally put the new cable into the trench for protection. The construction period of this scheme can not be guaranteed, and there is a great potential safety hazard. After many field investigations, the constructors boldly put forward the cable wall hanging scheme, which not only ensures the safety and construction period, but also provides a safe and fast "air corridor" for the future signal transformation of Dayaoshan tunnel. It is worth mentioning that after research and improvement, the signal equipment in the tunnel also adopts the synchronous wall hanging scheme, which not only increases the installation clearance, but also reduces the transitional construction amount after opening. This innovation has been gradually popularized and applied in the construction of signal cable laying in long and large tunnels of existing lines.