Determination of minimum overburden depth for underwater shield tunnel in sands:Comparison between circular and rectangular tunnels  

作　　者：Weixin Sun Fucheng Han Hanlong Liu Wengang Zhang Yanmei Zhang Weijia Su Songlin Liu 

机构地区：[1]School of Civil Engineering,Chongqing University,Chongqing,400045,China [2]Key Laboratory of New Technology for Construction of Cities in Mountain Area,Chongqing University,Chongqing,400045,China [3]National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas,Chongqing University,Chongqing,400045,China [4]School of Aerospace Engineering,Chongqing University,Chongqing,400045,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2023年第7期1671-1686,共16页岩石力学与岩土工程学报（英文版）

基　　金：support from National Major Scientific Instruments Development Project of China(Grant No.5202780029);Program of Distinguished Young Scholars,Natural Science Foundation of Chongqing,China(Grant No.cstc2020jcyjjq0087);Research on resilience prevention,control and adaptation strategy of flood disaster in megacities under changing environment(Grant No.2021-ZD-CQ-2).

摘　　要：With the development of global urbanization,the utilization of underground space is more critical and attractive for civil purposes.Various shapes of shield tunnels have been gradually proposed to cope with different geological conditions and service purposes of underground structures.Generally,reducing the burial depth of shield tunnel is conducive to construction and cost saving.However,extremely small overburden depth cannot provide sufficient uplift resistance to maintain the stability and serviceability of the tunnel.To this end,this paper firstly reviewed the status of deriving the minimum sand over-burden depth of circular shield tunnel using mechanical equilibrium(ME)method.It revealed that the estimated depth is rather conservative.Then,the uplift resistance mechanism of both circular and rectangular tunnels was deduced theoretically and verified with the model tests.The theoretical uplift resistance is consistent with the experimental values,indicating the feasibility of the proposed equations.Furthermore,the determination of the minimum soil overburden depth of rectangular shield tunnel under various working conditions was presented through integrated ME method,which can provide more reasonable estimations of suggested tunnel burial depth for practical construction.Additionally,optimizations were made for calculating the uplift resistance,and the soil thickness providing uplift resistance is suggested to be adjusted according to the testing results.The results can provide reference for the design and construction of various shapes of shield tunnels in urban underground space exploitation.

关 键 词：Minimum overburden depth Uplift resistance mechanism Shield tunnel shape Tunnel anti-floating 

分 类 号：TU43[建筑科学—岩土工程]