摘要
In this paper,a half-plane time-domain boundary element method is applied to obtain the seismic ground response,including a subsurface box-shaped lined tunnel deployed in a linear homogenous elastic medium exposed to obliquely incident SH-waves.Only the boundary around the tunnel is required to be discretized.To prepare an appropriate model by quadratic elements,a double-node procedure is used to receive dual boundary fields at corners as well as change the direction of the normal vector.After encoding the method in a previously confirmed computer program,a numerical study is carried out to sensitize some effective parameters,including frequency content and incident wave angle for obtaining a surface response.The depth and impedance ratio of the lining are assumed to be unvaried.The responses are illustrated in the time and frequency domains as two/three-dimensional graphs.The results showed that subsurface openings with sharp corners distorted the propagation path of the anti-plane waves to achieve the critical states on the ground surface.The present approach can be proposed to civil engineers for preparing simple underground box-shaped models with angular boundaries.
