考虑地基变形连续的基坑开挖诱发邻近盾构隧道位移预测  

Prediction of shield tunnel displacement due to adjacent basement excavation considering continuous deformation of ground

作　　者：应宏伟[1,2,3] 程康 俞建霖 徐日庆[1,2] 裘志坚 詹晓波[6] 秦建设 楼春晖 YING Hong-wei;CHNEG Kang;YU Jian-lin;XU Ri-qing;QIU Zhi-jian;ZHAN Xiao-bo;QIN Jian-she;LOU Chun-hui(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China;Engineering Research Center of Urban Underground Development of Zhejiang Province,Hangzhou 310058,China;Institue of Geotechnical Engineering Science,Hohai University,Nanjing 210098,China;China Railway 11th Bureau Group Co.Ltd,Wuhan 430061,China;Hangzhou Metro Group Co.Ltd,Hangzhou 310020,China;Zhongtian Construction Group Co.Ltd,Hangzhou 310008,China)

机构地区：[1]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058 [2]浙江省城市地下空间开发工程技术研究中心,浙江杭州310058 [3]河海大学岩土工程科学研究所,江苏南京210098 [4]中铁十一局集团有限公司,湖北武汉430061 [5]杭州地铁集团有限责任公司,浙江杭州310020 [6]中天建设集团有限公司,浙江杭州310020

出　　处：《浙江大学学报（工学版）》2021年第2期318-329,共12页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(41672264,51678523);浙江省重点研发计划资助项目(2019C03103)。

摘　　要：从工程实际出发,建立考虑基坑坑底及侧壁卸荷作用的基坑开挖引起的附加荷载计算模型;基于Mindlin解给出由基坑开挖所引起的邻近隧道处的竖向附加荷载;引入能考虑隧道任意埋深效应的修正基床反力系数,将既有隧道简化为搁置于Pasternak地基上的Euler-Bernoulli梁,进而提出基坑开挖下邻近既有隧道响应的简化计算方法.所提方法能考虑隧道埋深效应以及地基剪切效应,与工程实际更为接近.通过与三维有限元以及2组已发表工程实测数据的对比,验证所提简化计算方法的合理性与适用性.针对地基弹性模量、地基剪切模量、隧道纵向等效抗弯刚度、隧道-基坑夹角、隧道埋深、隧道-基坑间距以及基坑几何形状等主要参数对隧道纵向位移的影响进行系统分析.结果表明:隧道与基坑平行工况下的隧道最大位移是垂直工况下的1.60倍;提高隧道纵向抗弯刚度可以有效减小隧道的最大位移,但这种"削弱作用"会随隧道-基坑间距的增大而减小;随着隧道埋深、隧道-基坑间距的增大,隧道最大位移呈非线性递减规律;基坑的"长开挖"会影响隧道的位移和隧道隆起范围,而"短开挖"则主要影响隧道的位移.研究成果可以为较为合理地预测既有盾构隧道在邻近基坑开挖下的响应规律提供理论支持.A simplified vertical additional load calculation model of basement excavation,considering the unloading effect of bottom as well as sidewalls,was established based on the engineering practice.The vertical additional load at adjacent tunnel caused by basement excavation was given based on the Mindlin solution.A simplified calculation method was proposed for the response of tunnel subjected to an adjacent basement excavation,by introducing a modified subgrade reaction coefficient which could consider the arbitrary tunnel buried depth and regarding the existing tunnel as a continuous Euler-Bernoulli beam resting on Pasternak foundation.The proposed method could consider the effect of tunnel buried depth as well as the ground shear effect,closer to the engineering practice.The rationality and the applicability of the proposed method were verified by comparing it with the three-dimensional finite element method,as well as two groups of published engineering measured data.The main parameters such as elastic modulus and shear modulus of ground,the longitudinal equivalent bending stiffness of tunnel,the angle between tunnel and excavation,the embedded depth of the tunnel,the distance between tunnel and excavation as well as the geometric shape of excavation were all systematically studied.Results indicate that the maximum tunnel vertical displacement,when the tunnel was parallel to the excavation,was 1.60 times of that when the tunnel was perpendicular to the excavation.The maximum displacement of the tunnel can be effectively reduced by increasing the longitudinal bending rigidity of the tunnel,but this“reducing effect”will decrease with the increasing distance between the excavation and the tunnel.The maximum displacement of the tunnel exhibits a non-linear decreasing law with the increase of the tunnel buried depth and the distance between tunnel and excavation.The"long excavation"will affect the displacement and the uplift range of the tunnel,while the"short excavation"mainly affects the tunnel displacement.Resu

关 键 词：基坑开挖 隧道竖向位移 任意埋深 剪切效应 长开挖 短开挖 

分 类 号：TU375.2[建筑科学—结构工程]