The 7,152-meter controlling project — the Weihushan Tunnel on the Harbin-Mudanjiang Passenger Dedicated Line — is the second-longest tunnel within the Mudanjiang area. Recently, the reporter learned from China Railway 19th Bureau that the tunnel, by first introducing complete sets of technology, mechanized operations, and refined management during construction, has overcome difficulties such as complex geological conditions and heavy water inflow inside the tunnel, and is now driving forward in a sprint for the final 360 meters.
It is understood that the Weihushan Tunnel is located within Hengdaohezi Town, Hailin City. Because of the project's complex geological conditions, tight schedule, and relatively high construction difficulty, it was the earliest node project to start construction on the Harbin-Mudanjiang Passenger Dedicated Line and is also one of the major and difficult projects. Since construction began, the contractor has carried out uninterrupted 24-hour construction at six working faces of the tunnel. Up to now, the tunnel inlet section and No. 1 inclined shaft section, and the No. 1 inclined shaft and No. 2 cross adit section, have been successfully holed through. Construction personnel are making an all-out sprint on the final 360 meters of the outlet section, which is expected to be holed through by the end of August. Invert and secondary lining construction have also entered the sprint stage in parallel. Next, construction of the ballastless track tunnel base slab will be carried out, laying a solid foundation for full track laying.
According to the introduction, during construction some surrounding rock was found to be Class IV and V poor surrounding rock, and combined with relatively shallow soil cover, dangerous situations such as landslides and collapse were prone to occur during excavation. In order to smoothly solve the difficulties in tunnel construction, the project department adopted complete sets of technology and mechanized equipment as construction "sharp tools," accelerating the construction schedule through the use of complete sets of equipment. In the initial support shotcrete operations at each tunnel portal, the traditional small wet spraying machines were abandoned and four wet spraying robotic arms were deployed; the area of shotcrete applied per hour is five times the original, improving work efficiency, project quality, and the safety of tunnel construction.