非饱和全空间埋置隧道动力响应半解析模型

将非饱和地基土视为由固、液、气组成的三相介质,圆形隧道衬砌简化为无限长的Flügge薄壁圆柱壳,分别采用Helmholtz矢量分解定理以及分离变量法求解非饱和地基土的波动方程和Flügge薄壁圆柱壳的振动控制方程。结合位移和应力连续性等边界条件,建立移动简谐荷载下非饱和地基土中埋置隧道动力响应的半解析模型。基于该模型,探讨了非饱和地基土-隧道系统的动力响应特征及饱和度对系统动力响应的影响。结果表明,饱和度对土体的动位移、动应力、超孔隙水压力及土体临界速度等影响较大,计算时应考虑饱和度的影响。

Semi-analytical Model for Dynamic Response Calculation of Circular Tunnel Buried in Unsaturated Full-space

The unsaturated soil was conceptualized as three-phase medium, which consists of fluid, solid and gas, and the shield tunnel was simplified as an infinite Flügge cylindrical shell. The Helmholtz decomposition theorem was used to solve the governing equations of unsaturated soil and the separation-of-variable method was used to solve the motion equations of the Flügge shell. Based on the continuity boundary conditions of displacement and stress, a semi-analytical model for calculating the dynamic response of a tunnel buried in an unsaturated full-space was proposed. The dynamic response of the soil-tunnel system and the effect of saturation on the dynamic response were analyzed. The results show that the soil saturation has a great effect on the magnitude of soil displacement, soil stress, excess pore water pressure and critical velocity. Therefore, it is necessary to take the effect of saturation into account when calculating the dynamic response.