九绵高速主线实现贯通 全线今年通车 成都4小时飙拢九寨沟

Core Points - The successful completion of the Punan Tunnel marks the full connection of the Jiuzhai-Mianyang Expressway, laying a solid foundation for the highway to be fully operational this year [1][2] - The Jiuzhai-Mianyang Expressway is one of the most challenging highways under construction in Sichuan, and once completed, it will reduce the travel time from Chengdu to Jiuzhai Valley from 8 hours to 4 hours [2] Summary by Sections Project Completion - The Punan Tunnel is the last control project of the Jiuzhai-Mianyang Expressway, located in the Giant Panda National Park, with a left tunnel length of 2,747 meters and a right tunnel length of 2,719 meters [1] - The tunnel construction faced multiple challenges, including heavy rain, mudslides, and complex geological conditions [1] Construction Techniques - To ensure smooth project progress, the construction team utilized the already completed right tunnel to increase the working face through two vehicle passages and one expanded pedestrian passage [1] - During peak construction, six working faces were operated simultaneously, employing techniques such as "short advance, weak blasting, and strong support" along with "segmented deep hole grouting reinforcement" to address challenges in the mudflow section [1] Strategic Importance - The Jiuzhai-Mianyang Expressway, approximately 244 kilometers long, is a crucial segment of the G85 highway connecting Yinchuan to Kunming and serves as a major transportation route for Sichuan [2] - It is recognized as a typical demonstration project of a green highway by the Ministry of Transport and is significant for connecting Sichuan to Gansu, Qinghai, and Xinjiang [2]