At 4 p.m. on January 24, the tunnel on the Gangtou Station–Xuexiang Station section of Shenzhen Metro Line 10, built by CRCC South, broke through.
The Gangtou Station–Xuexiang Station section is 1,249.5 meters long, with a construction shaft in the middle. The vertical alignment is a V-shaped grade: after leaving Gangtou Station, the tunnel descends at 18‰ and then ascends at 28‰ to reach the section design terminus at Xuexiang Station. The tunnel has a cover depth of 18–23 meters and is constructed by the mining method. The section began breaking the portal face on October 28, 2016.
The Gangtou–Xuexiang section tunnel project is one of the important projects in the construction of Shenzhen Metro Line 10. The section mainly lies beneath Banxuegang Avenue and Zhonghao 1st Road, and passes under the foundation pit of the Kaisa Baoji project plot. Because most of the tunnel is in Grade V and VI surrounding rock, and the surrounding rock is completely to strongly weathered granite with high water content, it disintegrates into a flowing plastic state upon contact with water, making construction operations relatively difficult.
To overcome many difficulties in excavating Grade V and VI surrounding rock, such as large surface settlement and easy tunnel collapse, the project department invited experts from various parties many times to discuss construction plans and measures. In view of the particularity of construction operations in Grade V and VI surrounding rock, it formulated construction plans and safety emergency plans, optimized the excavation method, mainly adopting the ring-cut bench method, and used measures such as curtain grouting and large pipe roof inside the tunnel, together with surface grouting, strictly implementing the principle of "advance detection, advanced pipe roof, short advance, strong support, quick closure, and frequent measurement." During construction, the design and construction plans were strictly implemented, project management personnel worked on shifts 24 hours a day, the "three inspection" system was strictly implemented, and ground drilling and grouting were carried out for all sections where the tunnel passes under Banxuegang Avenue and Zhonghao 1st Road.
Through the concerted efforts of the project department and the work area to overcome difficulties, over 15 months, the China Railway 22nd Bureau, which undertook the construction task for this section, completed the tunnel breakthrough with "zero accidents," achieving the expected goal.