Vertical Roof Ripping Construction Techniques for Excavation of Main Tunnel from Inclined Shaft: A Case Study of the Large-span Metro Tunnel in Soft Surrounding Rock
(1 China Communications Construction Company (Guangzhou) Ltd., Guangzhou 511458; 2 School of Mechanics and Civil Engineering,State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116)
Abstract：
Aiming at the difficulty of deformation control during construction of main tunnel from inclined shaft for
a three-line large-span tunnel in soft surrounding rock, a construction method suitable for vertical roof ripping construction of urban metro tunnel from inclined shaft is proposed by taking the roof ripping construction of Xinlian running tunnel of Shenzhen rail transit as an example, and the construction scheme, procedures and key points are described. Furthermore numerical simulation is adopted to explore the rationality of this construction method. The research results show that: (1) it is an effective way to take roof ripping construction through small pilot tunnel to climb into main tunnel with reinforced support at the intersection; (2) reinforced support at intersection of inclined shaft and main tunnel can solve the construction difficulty caused by large dimension gap between them; (3) roof ripping construction through small pilot tunnel climbing to main tunnel provides precondition for the installation of primary
support of main tunnel arch frame and it is favorable for the main tunnel construction which switches to double sidewall construction later; (4) there is a stress relaxation zone of surrounding rock at intersection crown, and the rock mass displacement can be well controlled with roof ripping construction under the help of reinforced support.
LIU Yi1 ZHANG Yong1 PENG Zhen1 CHEN Jiawei2 LI Yuanhai
.Vertical Roof Ripping Construction Techniques for Excavation of Main Tunnel from Inclined Shaft: A Case Study of the Large-span Metro Tunnel in Soft Surrounding Rock[J] MODERN TUNNELLING TECHNOLOGY, 2020,V57(4): 201-207
2020, Vol. 57 