Influence of groundwater drawdown on excavation responses e A case history in Bukit Timah granitic residual soils

作     者：Wengang Zhang Wei Wang Dong Zhou Runhong Zhang A.T.C. Goh Zhongjie Hou 

作者机构：National Joint Engineering Research Center of Geohazards Prevention in Reservoir Area Environment Chongqing University Chongqing 400045 China School of Civil Engineering Chongqing University Chongqing 400045 China School of Civil and Environmental Engineering Nanyang Technological University 639798 Singapore 

出 版 物：《Journal of Rock Mechanics and Geotechnical Engineering》 (岩石力学与岩土工程学报（英文版）)

年 卷 期：2018年第10卷第5期

页      面：856-864页

核心收录：

学科分类：081401[工学-岩土工程] 08[工学] 0814[工学-土木工程] 

基　　金：the financial support from Land Transport Innovation Fund(LTIF)project funded by the Land Transport Authority(LTA) the support from General Financial Grant of the China Postdoctoral Science Foundation(Grant No.2017M620414) Special Funding for Postdoctoral Researchers in Chongqing(Grant No.Xm2017007) the Advanced Interdisciplinary Special Cultivation Program of Chongqing University(Grant No.06112017CDJQJ208850) 

主　　题：Braced excavation Bukit Timah granitic (BTG) residual soil Wall deflection Groundwater drawdown Empirical charts 

摘      要：Performances of a braced cut-and-cover excavation system for mass rapid transit （MRT） stations of the Downtown Line Stage 2 in Singapore are presented. The excavation was carried out in the Bukit Timah granitic （BTG） residual soils and characterized by significant groundwater drawdown, due to dewatering work in complex site conditions, insufficient effective waterproof measures and more permeable soils. A two-dimensional numerical model was developed for back analysis of retaining wall movement and ground surface settlement. Comparisons of these measured excavation responses with the calculated performances were carried out, upon which the numerical simulation procedures were calibrated. In addition, the influences of groundwater drawdown on the wall deflection and ground surface settlement were numerically investigated and summarized. The performances were also compared with some commonly used empirical charts, and the results indicated that these charts are less applicable for cases with significant groundwater drawdowns. It is expected that these general behaviors will provide useful references and insights for future projects involving excavation in BTG residual soils under significant groundwater drawdowns.