【摘要】 利用间接边界元方法在频域内求解了层状场地中任意形状沉积河谷对平面SH波的散射;利用土层的精确动力刚度矩阵求解了应力和位移的动力Green函数;结合间接边界元法,研究了沉积河谷宽度、厚度、入射角、入射频率等对地表位移幅值的影响,并与按一维场地模型计算的结果进行了比较。研究表明,沉积河谷有明显的二维散射效应,与一维模型的计算结果差别显著。在工程场地地震安全性评价中,应合理考虑沉积河谷对场地设计地震动参数确定的影响。更多还原

【Abstract】 The scattering of SH waves by an alluvial valley of arbitrary shape in a layered half-space is modeled using the indirect boundary element method(IBEM) in the frequency domain.The Green’s functions of displacements and stresses are calculated by using the exact dynamicstiffness matrix of soil layers.Based on IBEM,the effects of width and thickness of the alluvial valley,and the incident angle and frequency on the surface displacements are studied.These results are compared with that of one-dimensional model.The numerical results indicate: The two-dimensional scattering effect of alluvial valley is significant and quite different from that of one-dimensional model.The influence of alluvial valley on determination of design earthquake ground motion parameters should be considered reasonably in evaluation of seismic safety for engineering site.更多还原