At 10 a.m. on the 16th, as guests jointly pressed the launch button, a train carrying Qingdao's century-old metro dream slowly departed from Qingdao North Station, marking the official opening of the northern section of Qingdao Metro Line 3, Shandong Province's first metro.
Qingdao Metro Line 3 has a total length of 24.8 kilometers, spanning four administrative districts of Qingdao: Shinan, Shibei, Sifang, and Licang. It has 22 stations, including 6 transfer stations, with a total investment of 13 billion yuan.
Construction of the test section began in June 2009, and full-scale construction started in June 2010. The northern section opened for operation in December 2015, and the entire line is expected to be operational by the end of 2016.
Wang Chunguo, deputy general manager of the Tunnel Company of China Railway 14th Bureau Group and project manager of Qingdao Metro Line 3, was the only representative of the construction unit. As a recipient of the Shandong Province "Enriching the People and Prospering Shandong" Labor Medal and a Qingdao Model Worker, he was specially invited by Qingdao Metro Group to participate in the entire launch event. Since entering the site in June 2010, Wang Chunguo has led the project staff to overcome difficulties, achieve overall excellence in project construction, and lead the entire line, receiving high praise from the owner and all sectors of society.
The reporter learned that the civil engineering section 14 of Qingdao Metro Line 3, undertaken by the Tunnel Company of China Railway 14th Bureau Group, includes one station and two intervals. Among them, the Yongping Road-Fire Station interval tunnel passes under the Jiaozhou-Jinan Railway line. According to design requirements, after leaving Yongping Road Station, the tunnel runs east to west along Zhenhua Road, successively passing under Siliu Middle Road, the special line of the former No. 6 State Cotton Mill, and the Jiaozhou-Jinan Railway, then goes straight west into Qingdao North Railway Station. There are two major first-level risk sources in the section: the tunnel passing under the Jiaozhou-Jinan Railway and under five residential buildings from the 1970s.
The busy Jiaozhou-Jinan Railway has nearly 70 trains passing daily. Excavating a metro tunnel 9.9 meters underground is extremely difficult and risky. Once roadbed settlement occurs, the consequences would be unimaginable. "We must ensure zero settlement! This is our military pledge," said Wang Chunguo. As a major first-level risk tunnel, the project team continuously studied and demonstrated, carried out scientific construction, installed steel temporary beams at night, and seized every opportunity to work intensively during the two hours when trains were not running. On the Jiaozhou-Jinan Railway line outside the former No. 6 State Cotton Mill, from 11 p.m. to 1 a.m. every night, construction workers took advantage of the period when trains were not operating to replace steel sleepers, clean ballast on both sides, lay temporary beams, and manually dig pile holes. After completing a section, they had to restore it to its original state so that trains could pass normally.
The interval from Yongping Road to Qingdao North Railway Station in section 14 of Qingdao Metro Line 3 is 1,241 meters long and requires underground excavation under the Beiyuan Fengjing residential complex. Most buildings in this area were built in the 1970s and 1980s, with weak foundations and poor seismic performance. When the tunnel passes through, the burial depth is only 17 meters, and the geology is mostly backfill miscellaneous soil and moderately weathered granite, posing a high risk of blasting.
To ensure construction safety and reduce disturbance to old buildings and residents, Qingdao required that the vibration velocity of blasting construction be reduced from the national standard of 3.5 to 5 cm/s to within 1 cm/s. When using the mining method for blasting through old residential buildings, multiple scientific vibration reduction technologies were adopted to reduce the vibration velocity to 1 cm/s, reaching the domestic leading level. This comprehensive new vibration reduction method was used for the first time in domestic mining method metro construction and is innovative. In simple terms, it divides a single blast that ordinary people hear into several small blasts, with the earlier small blast creating expansion space for the later ones, thereby reducing the vibration velocity. Experts say this method is the first of its kind in domestic metro construction.
With strong construction strength and a good brand image, the Tunnel Company of China Railway 14th Bureau Group has successfully achieved rolling development in the Qingdao metro market. In addition to Metro Line 3, they have also undertaken Metro Line 2 and recently won the bid for Metro Line 1.
In an interview with the media at Metro Tower Station, Wang Chunguo said confidently: "I am a native of Qingdao, and I feel very proud to build a metro at my doorstep. We have participated in metro construction in 27 cities across the country, with shield tunneling crossing rivers, lakes, and seas, and we possess strong technical advantages and rich construction experience. We are confident and capable of building Shandong's metro projects well and living up to the expectations of our hometown folks for the 14th Bureau."