The longest shield section of Xiamen Metro Line 4 runs through two lines

On the morning of November 2nd, the shield tunneling machine of "Chenggong" successfully arrived at the shield receiving well of the right line of Pengcuo North Station. As the longest shield tunnel section of Xiamen rail transit project at present, the shield tunneling section of Subway line 4 and the Shield tunneling section of Hongpeng metro line 4 was successfully completed.

The single line of hongkeng Station - Pengcuo North Station is 2863.4 meters in length, with 1 intermediate air shaft and 4 connecting channels. The maximum longitudinal slope of the line is 28‰, the minimum plane curve radius is 900 meters, and the tunnel roof is buried 11 ~ 20 meters deep. The geology is granite complex strata, with complex stratigraphic structure, many types of rock and soil layers, bedrock uplift, and high strength of isolated rock, which has the characteristics of high safety risk, great technical difficulty in construction, and high requirements for settlement control.

Xiamen Railway Group strictly implements the primary responsibility of project quality of the construction unit. Since the launch of the left line shield machine of The Hongpeng Shield section on May 22, 2018, xiamen Railway Group has taken the initiative to lead the construction unit to take measures to overcome difficulties, invite experts to hold a consultation meeting on the key points and difficulties of construction, and conduct in-depth and serious analysis and research and plan optimization. To strengthen advanced drilling and pre-blasting in complex bedrock geology; Half section bedrock, the position of opening the warehouse is planned in advance, and the opening point is added. Plain concrete pile and WSS double liquid pre-grouting are adopted to reinforce the ground, and the warehouse is opened actively to reduce the time of opening the warehouse and changing tools. To optimize the tool configuration, select wedge alloy gear hob, strengthen rock breaking ability, improve driving efficiency; In order to solve the problem of gushing caused by abundant underground water in the process of tunneling, measures such as setting dewatering well on the ground to reduce water level are adopted to ensure the safety and speed up the construction progress.

Shield construction in the process of excavating HongPeng double success through bedrock around 1173.4 meters (including: the breeze bedrock is 845.1 meters, weathering bedrock of 328.3 meters, of which the breeze the rock saturated uniaxial compressive strength of 120 ~ 160 million mpa), overcome the soft down hard, hard and soft interlayer, boulder, shield body roll conversion knife work and cutter disc screw machine tool wear processing difficulties; It successfully crossed 7 urban roads including Xiang 'an Avenue, Xiang 'an West Road, Xibin Overpass, LNG gas pipeline, Hongzhong Avenue and viaduct, and crossed 3 integrated pipelines and 4 structures. In the process of shield tunneling, the left and right lines were opened 73 times under normal pressure, and 1227 single and double-edged hobs were replaced.

After the successful completion of the two lines of the Hongpeng Shield, Xiamen Railway Group will make further use of its successful experience, keep a close eye on the node targets of the remaining construction period, actively implement the "Dry 100 days" work requirements, reasonably allocate resources, scientifically organize the construction, and spare no effort to promote the project construction schedule.