Optimization and Application of the Construction Scheme for Large-section Tunnels in Water-rich and Weakly Cemented Strata
(1. School of Civil Engineering of Xi'an University of Architecture and Technology, Xi′an 710055; 2. Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering, Xi′an 710055; 3. China Railway Construction Bridge Engineering Bureau Group Co., Ltd., Tianjing 300300; 4. The No.1 Engineering Co., Ltd. of China Railway Beijing Engineering Group, Xi′an 710100)
Abstract：
In water-rich and weakly cemented strata, tunnel construction is very likely to induce the collapse of the surrounding rocks or serious large deformation of the support structure. This paper puts forward the lower double pilot tunnel construction method applicable for water-rich sandstone strata condition, based on the main tunnel construction of the 3# inclined shaft of the Taoshuping Tunnel on the Lanzhou-Chongqing Passenger Dedicated Line.Meanwhile, it adopts an integrated dewatering scheme of vacuum light well point + water collection well for advanced dewatering of the tunnel to reduce the construction difficulties. Using numerical analysis and on-site monitoring method, it analyzes and evaluates the reasonableness and effectiveness of the construction scheme. The results show that when the lower double pilot tunnel construction method is used, the vault settlement and clearance convergence are 50 mm and 32 mm respectively, while the maximum contact pressure on the support structure is 135.3 kPa, and the deformation and stress of the support structure are both within the acceptable range with the tunnel structure being safe and stable. The lower double pilot tunnel construction method has been successfully applied to the Taoshuping Tunnel, providing references for the construction of extra-large section tunnels in water-rich and weakly cemented strata or soft rock strata.
WANG Huaizheng1 SONG Zhanping1,
2 ZHANG Xuewen3 TIAN Xiaoxu1,
2 PAN Hongwei4
.Optimization and Application of the Construction Scheme for Large-section Tunnels in Water-rich and Weakly Cemented Strata[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(2): 210-219
2022, Vol. 59 