On August 28, the Hojiazhai Extra-long Tunnel of the National Expressway Network Yinbai Line (G69) Shaanxi Section of An (Kang) to Lan (Gao) Expressway Project was successfully completed. This is the first super-long tunnel of Anlan high-speed project to realize double-span linking. It has laid a solid foundation for Anlan high-speed project to help Shaanxi overcome poverty and achieve the goal of "13th Five-Year Plan" County-to-county high-speed.
It is understood that the Hejiazhai Extra Long Tunnel is 4202 metres long and has two-way four lanes. It adopts separate design. The maximum depth of the tunnel is about 459.7 metres, and the bamboo-cutting portal is used at the entrance and exit of the tunnel. The project is constructed by China Jiaotong No. 1 Public Bureau Group. Since the end of 2016, all the construction staff have overcome the geological disasters such as floods, debris flow and landslides on the sidewalk. The construction procedure of "simultaneous construction of left and right tunnels and parallel operation of each working procedure" has been adopted to promote the tunnel excavation work rapidly and safely.
According to the relevant person in charge of the project manager, experts have been invited to discuss the construction scheme many times during the project construction process, and the site personnel of the tunnel have been organized to hold a final meeting on the quality and safety of the construction. The principles of "short footage, weak blasting, strong support, frequent measurement and quick closure" have been strictly implemented. On the premise of guaranteeing the safety and quality, the construction scheme has been combined. Arrangement of construction organization, meticulous management, optimization and perfection of excavation and excavation schemes, strict implementation of the standardized guidelines for Expressway construction, using the "short, tight, fast and diligent" model, and taking various effective measures to overcome the difficulties of poor surrounding rock level and difficult construction organization, so as to open the Anlan Expressway to traffic on schedule. It has made positive contributions.
