en.Wedoany.com Reported - On April 29, the total boring footage of the Rierlang Mountain Tunnel, undertaken by the Second Division of the Sichuan Section Headquarters of the Xining-Chengdu Railway under the Tunnel Branch, exceeded 2,000 meters. The tunnel project is located on the Western Sichuan Plateau in Sichuan Province, China, with an entrance elevation of 3,430 meters and an exit elevation of 3,493 meters. Extreme low temperatures can reach minus 30 degrees Celsius, and the oxygen content is only 60% of that at sea level.
The tunnel construction faces the dual challenges of high altitude, low oxygen, and complex geological conditions. Grade V surrounding rock accounts for over 95%, characterized by loose rock mass and poor self-stability, traversing dense zones of karst and fault zones. The daily water inflow exceeds 3,000 cubic meters, requiring repeated grouting 3 to 5 times to form a sealing layer. The compressive strength of the rock mass in the fault fracture zone is less than 15 MPa, necessitating the densification of steel arch frames to a spacing of 0.6 meters and the addition of pipe roof lock feet. The concrete batching plant uses floor heating for continuous insulation, and transport mixer trucks must be wrapped with insulation layers before hitting the road.
The project team adheres to the construction principles of "advance pipe support, strict grouting, short boring footage, rapid closure, strong support, and frequent measurement." For the fault fracture zone, advance conduit grouting reinforcement is adopted; in water inflow areas, a combined "drainage and sealing" treatment is implemented. Techniques such as deep-buried central drainage ditch construction equipment and steam curing systems are promoted and applied, and a lining cold-proof insulation layer is installed. In terms of safety and environmental management, the project has cumulatively conducted 28 safety training sessions, rectified 203 hazards, and delivered 722 pre-shift briefings. In the fragile plateau ecological zone, the tunnel project implements measures such as turf stripping and conservation, synchronous vegetation restoration, circulating wastewater treatment, and the establishment of livestock passageways.
Upon completion of the Xining-Chengdu Railway, the train travel time from Xining to Chengdu will be shortened from 13 hours to 4.5 hours, the annual freight capacity will increase by 30 million tons, serving 20 million people along the route.
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