The Mianzhu-Maoxian Highway is Expected to Fully Open to Traffic by the End of the Year

"This is the earliest year to resume the work after the Spring Festival. In order to seize working hours, some workers stayed at the construction site and did not go home for the Spring Festival." On February 19, the eighth day of the first lunar month, the reporter came to the exit of Donghe No. 2 Tunnel on Mianzhu-Maoxian Highway (or Mianmao Highway), and found that the workers in the tunnel kept busy, and there were dump trucks carrying the muck out of the tunnel from time to time. By the end of this year, the Mianmao Highway is expected to fully open to traffic. It has become a norm to race against time and catch up with the schedule.

Running against time

Commencing construction on the seventh day of the first lunar month

Starting from Qingping Town, the reporter followed the project construction party to wind their way along the makeshift road built in Qingping River channel for more than 20 kilometers. After 40 minutes of driving, we arrived at the exit of Donghe No.2 Tunnel on Mianmao Highway.

According to Zhang Haiping, Party branch secretary of the Engineering Project Manager Department, Mianzhu section of SRBG Mianzhu-Maoxian Highway, more than 50 workers stayed at the construction site instead of going home for the Spring Festival in order to catch up the schedule. "Just after the fifth day of the first lunar month, we began to prepare for the organization of construction. On the seventh day of the first lunar month, we carried out the blasting to officially start the work."

The Mianzhu section of Mianmao Highway starts from Huangguandeng in Hanwang, goes up along Mianyuan River, passes Qingping Town, passes through Jiudingshan Nature Reserve and Giant Panda National Park, and ends at Lanjiayan Tunnel, with a total length of 47.49 kilometers. It is designed in accordance with the Class II standard, with a seismic defense level of 8 and a design speed of 40 kilometers per hour. The estimated total investment is RMB2,560.32 million, including RMB1 billion of support fund from Hong Kong.

The Mianzhu section of the Mianmao Highway is divided into three phases. Construction started in September 2009. The first phase of the project is the section from Huangguandeng in Hanwang to Nanmugou, with a total length of 8.465 kilometers, which was completed and opened to traffic at the end of 2012. The second phase is the reconstruction works of Mianmao Highway after the "August 13" disaster. The section is 33.1 kilometers long, with 29 bridges with a total length of 3.89 kilometers and 15 tunnels with a total length of 25.47 kilometers, with a bridge-tunnel ratio of 81.1%. Among them, the section from Nanmugou to Qingping was completed on May 31, 2016; the section from Qingping Town to the exit of Heitan Tunnel was completed at the end of October 2016; the section from the exit of Heitan Tunnel to Niujuangou is scheduled to be completed and open to traffic by the end of 2021. The third phase is the Lanjiayan Tunnel and connecting engineering (Mianzhu section), in which the main tunnel of Mianzhu section is 4,414 meters long, and the parallel guide tunnel is 4,428 meters long. Construction of the phase started on October 15, 2015, and is scheduled to be completed by the end of 2021.

Challenges in construction process

Digging 0.5 meters into the tunnel every day

"It is so difficult to build the Mianmao Highway. The local flood season starts in May and lasts until October, and the effective construction period is only five to seven months per year." Zhang Haiping said, in addition to the short construction period, because the site is mountainous, there are a lot of stones, the geological structure is complex, many places do not have the construction conditions, greatly increasing the difficulty of the project.

For example, the Donghe No. 2 Tunnel, with a total length of 1,390 meters, was found to be unsuitable for construction due to that the level of surrounding rock at the top of the hill was low, and the water would flow out of the mud once the tunnel was excavated. Therefore, it can only be built and managed at the same time. Only 0.5 meters can be dug into the tunnel each day, starting from the six ports on the face of the tunnel. There are 395 meters left, which is expected to be completed by the end of April.

According to staff from the Mianzhu-Maoxian Highway Company, the remaining 187 meters of the Lanjiayan Tunnel, 152 meters of the Donghe No. 1 Tunnel and 398 meters of the Donghe No. 2 Tunnel on the Mianzhu section of the Mianzhu-Maoxian Highway, as well as seven bridges, are under construction.

"We are working overtime now in the hope that we can catch up with the progress before the flood season, so as to take the repaired road instead of the rough makeshift road during the construction process." Zhang Haiping, who has been working on the project for eight years, said, "I hope the final year of the battle can be quickly pushed forward, and the project will be completed on schedule." (Reporter Chen Xiaoxia)

 

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