内源瞬态荷载作用下弹性介质与饱和多孔介质中衬砌隧道的动力响应对比分析

衬砌隧道周围介质不同，其内源瞬态荷载作用下的动力响应不同，该文对弹性介质与饱和多孔介质中作用有内源荷载的衬砌隧道的动力响应进行对比分析。首先，令饱和多孔介质孔隙率n=0，将衬砌周围饱和介质退化为弹性介质，动力响应解答相应退化为弹性介质中的解答，退化解与已有的隧道周围为弹性介质时的动力响应解答完全一致。其次，对不同孔隙率的饱和多孔介质和理想弹性介质中衬砌隧道的动力响应进行计算，结果表明：与弹性介质相比，饱和多孔介质中衬砌内表面的动力响应较大，轴向衰减速度较快；随着孔隙率的减小，饱和土中衬砌内表面的动力响应逐渐减小，位移和应力时程曲线均趋近于弹性介质。

The Comparison of Dynamic Response of Lined Tunnels under Internal Loading between Two Surrounding Media: the Elastic Medium and the Saturated Porous Medium

Considering the dynamic interaction between lining and soil and the difference in dynamic response to the internal blast load between different soil media surrounding the lined tunnel, the dynamic responses of lined tunnels subjected to an internal blast load in the saturated medium and the elastic medium are compared and studied. First, the porosity of saturated medium surrounding the lining structure is set as n=0, which is degenerated into the elastic medium, and the solution to the dynamic response of saturated medium is then degenerated into the solution of elastic medium. This degenerate solution is completely consistent with the existed solution to the dynamic response of elastic media surrounding the lined tunnel. Subsequently, the dynamic responses of lined tunnel in saturated soil with different porosities and ideal elastic medium are computed and compared. It is found that (a) compared with the elastic medium, the dynamic response of lined tunnel in saturated medium is larger, and the attenuation of the response along the axis is faster; (b) the dynamic response at the inner surface of lining in the saturated medium increases gradually with the decrease of porosity, meaning that the trends of time-history curves of displacement and stress at the inner surface of lining in the saturated medium are similar to those in the elastic medium as the porosity decreases.