On April 18, the No. 1 Xiawan Tunnel of the Songli Section of the Songli Section of the Quzhou-Lishui Railway, which was constructed by the Fourth Company of China Railway Tenth Bureau, was successfully completed. As the first kilometer single-track tunnel and an important control project of the Quli Railway adjacent to the business line, the smooth breakthrough of the Xiawan No. 1 Tunnel provides favorable conditions for the Jinwen Freight Line realignment project.
China Railway Tenth Bureau is one of the important participating units of Quli Railway, mainly responsible for the second and third bids of the Songyang to Lishui section of the Quli Railway, and the construction scope is from Songyang Station of Quning Railway (inclusive) to Lishui Station of Jinliwen Railway (inclusive), including Lishui Passenger Train Relief Line, Songyang and Lishui Station Renovation, Jinwen Line Realignment and other projects. Xiawan No. 1 Tunnel is located in Liandu District, Lishui City, Zhejiang Province, with a total length of 1104.85 meters and a maximum buried depth of about 82.5 meters, which is a single-hole single-track tunnel with a speed of 80Km/h, which is one of the important projects of the first phase of the Quli Railway Project.
The tunnel has a small cross-section, low strength of the surrounding rock, frequent changes in the grade of the surrounding rock, many fracture zones, and is adjacent to the existing Jinwen freight line, Jinliwen high-speed railway, and Jinliwen natural gas transmission main pipeline, which has high requirements for blasting vibration speed control, and large pressure on safety and construction period.
In the face of many unfavorable factors, the project department formulated a realistic construction plan and plan, continuously strengthened the implementation of the construction period, and refined the node goals; the team had a clear division of labor and responsibilities, and carefully organized various departments and operators to sort out every process of the tunnel. Through UAV aerial photography of terrain and distribution of dangerous rocks, formulate a dangerous rock investigation plan at the tunnel entrance, and mark dangerous rocks and solitary rocks with a diameter of 0.3~2m in accordance with the requirements of "one stone and one file", and clean up the files one by one.
The tunnel blasting scheme is based on the principles of technical feasibility, safety and reliability, and economic reasonableness, according to the environmental characteristics, geological structure and construction methods of the tunnel, comprehensively considering the impact of drilling and blasting construction on the engineering structure and the surrounding environment, and on the premise of ensuring the safety of construction, the micro-difference, divisional, multi-section, and multiple weak blasting technologies are adopted, and the blasting scheme is reasonably optimized with the construction progress of the project.
The blasting operation will carry out the "fixed personnel, fixed drilling rigs, fixed parts, fixed quantity, fixed time, and fixed responsibilities" throughout, highlighting the safety and controllability of the whole process; professional and technical personnel will be stationed at the construction site to guide and supervise the whole process, control the phenomenon of over-under-excavation of the tunnel, and improve the quality and efficiency of excavation; through the inspection and supervision system of the project leadership team, control the number of workers in the tunnel, regularly detect harmful gases, and ensure personal safety; and ensure that the safety management of the construction site is controllable and efficient through information measures such as face recognition and real-time monitoring and positioning.
Up to now, 63% of the earthwork of Quli Railway II. and III. subgrade projects has been completed, 96% of the total bored piles of bridge projects have been completed, 85% of the total amount of bearing caps have been completed, 81% of the total number of piers have been completed, 39% of the total cast-in-place beams have been completed, 70% of the total amount of excavation support of tunnel projects have been completed, and 50% of the total amount of lining excavation has been completed. In the next step, the project department will keep an eye on the time node, optimize resource allocation, strengthen process supervision, implement safety responsibilities, and ensure the efficient progress of the project.
Quli Railway is a supporting project for the construction of the "Great Garden" transportation channel in Zhejiang, which is mainly responsible for passenger and freight transportation in Central and Southwest China through Quzhou, Lishui and Wenzhou. After it is put into operation, it is of great significance to improve the layout of the road network in southwest Zhejiang, accelerate the development of tourism resources along the route, promote the high-quality development and construction of a common prosperity demonstration zone in Zhejiang, and promote the economic and social development along the route.
Photo: Kong Chen, Sun Xiaokang