AUTHOR=Nong Xingzhong , Liang Yuehua , Ruan Yanmei TITLE=A Case Study of Deep Shaft and Open Face Tunnelling Induced Excessive Ground Settlement in Water Rich Strata in Guangzhou, China JOURNAL=Frontiers in Earth Science VOLUME=10 YEAR=2022 URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2022.825186 DOI=10.3389/feart.2022.825186 ISSN=2296-6463 ABSTRACT=

During a shaft and associated sprayed concrete lining (SCL) tunnel construction in a new line of Guangzhou Metro, site monitoring recorded ground surface settlement was much larger than that predicted in the design. This raised the alarm to the safety of an adjacent high-pressure gas pipe. Close-form and analytical calculations and non-coupled and coupled numerical analyses were carried out to back analyze the settlement. It was found the primary contributing factor to the excessive ground settlement is water loss-induced ground consolidation, which is commonly encountered during underground construction in south China where complex strata, such as granite residual soil and fully weathered granite, are present. This paper details the back analysis process and discusses mitigation measures that should be adopted for construction in similar ground in the future.