Large deformation problems arising from deep excavation in silt strata:A case study in Shenzhen,China  

作　　者：Xuefeng Ou Wei Liao Xiangcou Zheng Guofu Yang Ashraf S.Osman 

机构地区：[1]College of Civil Engineering,Changsha University of Science and Technology,Changsha,410114,China [2]Department of Engineering,University of Durham,Durham,DH13LE,UK [3]School of Civil Engineering,Central South University,Changsha,410075,China [4]Shenzhen Municipal Design and Research Institute Co.,Ltd.,Shenzhen,518060,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2025年第4期2576-2589,共14页岩石力学与岩土工程学报(英文)

基　　金：supported by the National Natural Science Foundation of China (Grant Nos.52008039 and 52308425);the Natural Science Foundation of Hunan Province (Grant No.2021JJ40592).

摘　　要：Deep excavations in silt strata can lead to large deformation problems,posing risks to both the excavation and adjacent structures.This study combines field monitoring with numerical simulation to investigate the underlying mechanisms and key aspects associated with large deformation problems induced by deep excavation in silt strata in Shenzhen,China.The monitoring results reveal that,due to the weak property and creep effect of the silt strata,the maximum wall deflection in the first excavated section(Section 1)exceeds its controlled value at more than 93%of measurement points,reaching a peak value of 137.46 mm.Notably,the deformation exhibits prolonged development characteristics,with the diaphragm wall deflections contributing to 39%of the overall deformation magnitude during the construction of the base slab.Subsequently,numerical simulations are carried out to analyze and assess the primary factors influencing excavation-induced deformations,following the observation of large deformations.The simulations indicate that the low strength of the silt soil is a pivotal factor that results in significant deformations.Furthermore,the flexural stiffness of the diaphragm walls exerts a notable influence on the development of deformations.To address these concerns,an optimization study of potential treatment measures was performed during the subsequent excavation of Section 2.The combined treatment approach,which comprises the reinforcement of the silt layer within the excavation and the increase in the thickness of the diaphragm walls,has been demonstrated to offer an economically superior solution for the handling of thick silt strata.This approach has the effect of reducing the lateral wall displacement by 83.1%and the ground settlement by 70.8%,thereby ensuring the safe construction of the deep excavation.

关 键 词：Silt strata Deep excavation Large deformation Deformation mechanism Treatment measures 

分 类 号：TU753[建筑科学—建筑技术科学]