盾构法隧道纵向地震响应特性

采用土—结相互作用的动力有限元法,引入无长度的3自由度弹簧单元模拟纵向螺栓接头,分析行波波长、地基刚度与阻尼对盾构法隧道纵向地震响应的影响。分析结果表明:行波从水平方向输入时有突变弯矩产生,突变弯矩随波长和阻尼的增大而减小,而地基刚度系数对突变弯矩的影响相对较小;行波作用下,产生的接头最大轴力及最大弯矩值均随波长的增大而减小,而地基刚度系数及阻尼系数取值对最大弯矩值的影响较小。因此,建议在实际工程设计计算中要重视输入地震动参数的选择,且取较小的阻尼系数。

Characteristics of the Longitudinal Seismic Response of Shield Tunnel

With dynamic finite element method considering soil-structure interaction effects,this paper analyzes the influences of traveling wavelength,foundation stiffness and damping coefficient on the longitudinal seismic response of shield tunnel by simulating longitudinal screwed joint with zero-length,three-degree of freedom spring element.Analysis results show that the breaking bending moment occurs when the traveling wave is input from horizontal direction.The breaking bending moment will decrease with the increase of wavelength and damping coefficient.The coefficient of foundation stiffness will have less impact on the breaking bending moment.The maximum axis force and moment of the segment joint under the action of traveling wave will decrease with the increase of wavelength.The values of foundation stiffness coefficient and damping coefficient will have less impact on the maximum moment.As a result, it is suggested that,for the design calculation of practical engineering,importance should be attached to the selection of the dynamic parameters of earthquake input,and smaller damping coefficient should be adopted.