盾构隧道地震响应的三维数值模拟方法及应用

在盾构隧道传统抗震分析方法基础上,针对上海一新建盾构越江隧道,提出以完全拟实仿真为特点的大规模盾构隧道地震响应的三维数值模拟方法,建立包括地基土、盾构隧道以及联络通道等多个对象在内的三维分析模型,整体的单元数和节点数均达到了4×106左右。模型考虑地基土的材料非线性,以及土体–隧道间、管片–管片间的接触非线性因素,最后利用动态显式算法及其关键技术进行基于高性能计算机的大规模地震响应分析。计算结果反映地基土–盾构隧道体系在地震荷载作用下的相互作用和变形,并对隧道衬砌结构中的管片应力以及连接螺栓的受力变化进行深入分析。

THREE-DIMENSIONAL NUMERICAL SIMULATION METHOD AND ITS APPLICATION TO SEISMIC RESPONSE OF SHIELD TUNNEL

Emphasizing the importance of research on seismic response of shield tunnel and depicting its extinct features during earthquake,different traditional antiseismic analysis methods for shield tunnel are discussed with the merits and demerits pointed out by comparison.Then,aiming at a newly-built shield tunnel in Shanghai,a three-dimensional numerical simulation method for large-scale seismic response of shield tunnel is proposed with the character of fully emulating to the reality.Firstly,some basic and crucial theories and methods are introduced,including explicit finite element algorithm,time step control,hourglass control and dynamic relaxation.The three-dimensional analytical object is constructed from geometrical model to finite element model,which consists of surrounding soil,shield tunnel,connecting passages and many other objects with the total number of nodes and elements 4 million respectively.This model takes nonlinear behaviors of soil and contact interface between soil and tunnel into account;and the contact interfaces between lining segments are also considered.Final calculation is successfully completed on a high-performance computer.According to the calculation results,the whole tendency of shield tunnel reflecting heave and settlement are achieved,which reveals the interaction and distortion of the foundation soil-shield tunnel system under seismic loading.Besides,both the stress in lining segments and axial force in connecting bolts are investigated and analyzed respectively;and typical curves of force or stress variation with time are selected and illustrated in detail.Also,the stress distributions on the connecting passages and lining segments are shown;and corresponding weak zones are indicated consequently.In a word,it provides a practical method and meaningful data for the further research on aseismic design and research of shield tunnel.