Study and Application of the Double Pilot Tunnel Construction Method
(1 School of Civil Engineering, Beijing Jiaotong University, Beijing 100044; 2 China Railway First Survey and Design Institute Group Ltd., Xi'an 710043; 3 China Railway 21st Bureau Group Co. Ltd., Lanzhou 730000)
Abstract：
Considering the characteristics of water-bearing and slightly cemented sandstone, a double pilot tunnel construction method is proposed using the pros and cons of different conventional construction methods based on the No.3 inclined shaft of the Taoshuping Tunnel on the Lanzhou-Chongqing Railway. Using FLAC3D numerical analysis software, the regularities of ground deformation and the stress condition of the supporting structure during pilot tunnel construction were studied regarding actual geological conditions. The influence of different excavation steps was analyzed. Finally, the most dangerous part of the supporting structure was analyzed. The importance of dewatering in this type of ground is addressed. This study and its application results show that this construction method could control ground deformation effectively.
2013, Vol. 50 