采用一种高精度的间接边界积分方程法,对弹性半空间中衬砌隧道对入射瑞利的二维散射问题进行求解分析。结果表明:衬砌隧道和非衬砌隧道对瑞利波的散射具有显著的差别,衬砌刚度对波的散射规律具有重要影响。隧道附近地表动力响应和隧道衬砌动应力集中主要取决于衬砌和围岩的刚度比、隧道的埋深和直径、入射波频率等因素。对于柔性衬砌,浅埋隧道对低频瑞利波会产生显著的位移放大效应;对于刚性衬砌,衬砌内壁的动应力集中效应十分明显。整体上看,随着埋深的增大,隧道周围波的散射逐渐减弱。
Two-dimensional scattering of incident Rayleigh waves by a lined tunnel in elastic half-space is solved and analyzed by the high-precision indirect boundary integral equation method(IBIEM).It is found that the scattering around the lined tunnel may be significantly different from that around the unlined tunnel;and the lining stiffness has a great effect on the wave scattering.The dynamic response and dynamic stress concentration depend considerably on the stiffness ratio of the lining to the surrounding soil,the embedded depth and the radius of the tunnel,the frequency of incident waves,etc.For the soft lining,there is a large displacement amplification for the case of shallow tunnel.While for the rigid lining,the dynamic stress concentration at the inner surface of the lining is very large.In the whole,the scattering of Rayleigh wave around the tunnel gradually weakens as the depth of tunnel increases.