摘要
违规临时地表堆载将引起地层附加应力,对既有盾构隧道产生不利的影响,严重者将导致隧道结构破坏。现有方法多是将隧道简化为搁置于Winkler地基的Euler-Bernoulli梁,不能考虑隧道的剪切变形和隧道埋深对基床反力系数的影响。针对既有研究的不足,提出考虑隧道剪切效应和隧道埋深的地表堆载下既有盾构隧道变形和受力的简化解析解。将既有盾构隧道简化为搁置于Winkler地基的Timoshenko梁,地基反力系数考虑隧道埋深的影响。通过三维有限元模型和已发表工程案例的实测数据,验证所提方法的正确性及适用性。通过参数分析发现,在荷载中心与隧道中心距离较近情况下,浅埋盾构隧道将发生较大的沉降变形;提高等效抗弯刚度和基床反力系数可以减少隧道沉降变形。而增大等效剪切刚度对隧道的沉降变形贡献较小,但是可以明显减小管片之间的错台变形。该研究成果可为合理预测地表堆载对既有盾构隧道的影响提供一定的理论支持。
Illegal temporary surface surcharge can induce additional ground stress, which may cause adverse effects or damage to the existing shield tunnel structure. However, current methods for predicting tunnel longitudinal responses to surface surcharge generally simplify the tunnel as an Euler-Bernoulli beam resting on Winkler foundation, which ignores the shearing deformation of shield tunnel and cannot consider effect of the burial depth on the coefficient of subgrade reaction. In this study, a new analytical method is developed to evaluate the existing shield tunnel deformation subjected to surface surcharge, considering the tunnel shearing effect and the burial depth of the tunnel. In the proposed method, the shield tunnel is treated as Timoshenko beam resting on Winkler foundation and the effect of burial depth of shield tunnel on the coefficient of subgrade reaction is considered. The effectiveness and feasibility of the proposed method is verified by a three-dimensional finite element analysis and measured data from a case. Parametric analysis indicates that a shallowly buried shield tunnel suffers large settlement when the distance between the load center and tunnel axis is relatively close. Increasing the equivalent bending stiffness and the coefficient of subgrade reaction would remarkably reduce tunnel settlement. The tunnel settlement was hardly sensitive to equivalent shear stiffness. However, increasing equivalent shear stiffness would significantly reduce the dislocation between the adjacent rings. In general, the proposed method will serve to be theory support for reasonably predicting the shield tunnel responses to surface surcharge.
作者
康成
梅国雄
梁荣柱
吴文兵
方宇翔
柯宅邦
KANG Cheng;MEI Guo-xiong;LIANG Rong-zhu;WU Wen-bing;FANG Yu-xiang;KE Zhai-bang(Faculty of Engineering,China University ofGeosciences,Wuhan,Hubei 430074,China;College of Civil Engineering and Architecture,Guangxi Universlty,Nanning,Guangxi 530004,China;Key Laboratory of Engineering Disaster Prevention and Structural Safety of Ministry of Education,Guangxi Umverslty,Nanning,Guangxi 530004,China;Guangxi Key Laboratory of Disaster Prevention and Structural Safety,Guangxi University,Nanning,Guangx 530004,China;Anhui Institute of Building Research &Desxgn,Hefei,Anhui 230001,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第12期4605-4616,共12页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.41807262,No.51678547)
中央高校基本科研业务费专项资金资助项目(No.CUG170647)
湖北省自然科学基金(No.2018CFB179)~~
关键词
地表堆载
盾构隧道
理论解析
隧道变形
surface surcharge
shield tunnel
theoretic analysis
deformation of tunnel