On February 18, the second day of the Lunar New Year, Miyaluo Town in Aba Prefecture was immersed in festive joy. About 4 kilometers from the town, loud blasts echoed from the No. 3 Tunnel of the Wenchuan-Ma'erkang Expressway. Deep inside the tunnel, excavation was underway.
Entering from the tunnel portal, at about 1,300 meters in, is one of the tunnel's working faces. Huge searchlights illuminated the site as bright as day, and a 1.8-meter-diameter ventilation pipe roared, continuously supplying fresh air. At the end of the tunnel stood a 6-meter-high work platform vehicle, with the work frame divided into three levels, each with four workers standing, holding pneumatic drills and working intensively on the tunnel face ahead.
“We are drilling holes,” said Asu Tieha, leader of the pneumatic drill team. In the entire process of tunnel excavation, drilling is the first step: strictly following the drill-and-blast design, locating precise positions, drilling to the appropriate depth according to the surrounding rock conditions, and then carrying out blasting, mucking, and support operations. However, in the Miyaluo Tunnel, drilling is not the first step—as a high-gas tunnel, the Miyaluo Tunnel requires continuous monitoring of gas concentration before and during drilling.
Not only before drilling. In November 2016, after gas was detected during tunnel construction, the tunnel's protection level was fully upgraded, with intelligent monitoring and manual inspection online 24 hours a day for real-time safety monitoring. Yang Jie, the on-site manager, introduced that before and after each blast, three inspections are conducted to ensure safety.
After about three hours of work, the drilling process was completed. The blasting team entered, and non-essential personnel withdrew from the site. More than an hour later, a muffled blast sound came from inside the tunnel. Outside, several muck trucks were ready to take over the next work.
“All teams work in three shifts, with people resting but the working face never resting, achieving 24-hour continuous construction,” said Hu Guanghua, project manager of the C18 section of the Wenchuan-Ma'erkang Expressway for China Railway 20th Bureau Group Second Engineering Co., Ltd. The Miyaluo No. 3 Tunnel currently has five working faces, all operating day and night, with each face advancing at a speed of more than 1.5 meters per day.
Not only does work continue every day, but during the Spring Festival holiday, tunnel construction did not stop for a single day. More than 200 people gathered at the construction site and spent an unforgettable “site New Year.” To boost morale, on the first day of the Lunar New Year, Zheng Runhuai, a member of the Party Committee of China Railway 20th Bureau Group, came to the site to celebrate the New Year with everyone.
The reason for such “hard work” is to complete and open the Wenchuan-Ma'erkang Expressway project as soon as possible. Hu Guanghua introduced that the Wenchuan-Ma'erkang Expressway is a major transportation project for poverty alleviation in Sichuan Province. The Sichuan Provincial Department of Transportation has proposed the goal of opening 100 kilometers ahead of schedule in 2018. Among the Miyaluo Tunnel Group, which is most likely to be completed first, Tunnels No. 1 and No. 2 have already been holed through, leaving only Tunnel No. 3 under construction. “According to the current construction progress, by the end of this year, it is expected to have expressway access all the way from Miyaluo to Ma'erkang!”