ABSTRACT

It is well known that seismic events at sea can lead to severe effects on marine facilities. A seismic event can generate amplifications due to local conditions of the place, that is, site effects. In this work, we show numerical results of seismic amplifications on the seabed where there is the presence of deposits formed by soft soils. We formulate the problem using an Indirect Boundary Element Method. In this formulation, we consider that the total field of displacements can be expressed in terms of an incident and another diffracted field. Specifically, the diffracted field is expressed in terms of Fredholm integral equations of second kind and zero order. This conceptualization can also be understood as the implementation of the Huygens Principle because the waves are constructed at the boundary from which they are irradiated. We study five geometries of soft deposits. In general, we found that P (compressional) waves can generate seismic amplifications of up to 45 times while SV (shear) waves cause amplifications up to 65 times.

摘要

众所周知，海上地震事件会对海洋设施造成严重影响。由于地方的当地条件，即场地效应，地震事件会产生放大效应。在这项工作中，我们展示了存在由软土形成的沉积物的海底地震放大的数值结果。我们使用间接边界元方法制定问题。在这个公式中，我们认为总位移场可以用一个入射场和另一个衍射场来表示。具体来说，衍射场用第二类和零阶的 Fredholm 积分方程表示。这种概念化也可以理解为惠更斯原理的实施，因为波是在它们被照射的边界处构造的。我们研究了五种几何形状的软沉积物。一般来说，我们发现 P（压缩）波可以产生高达 45 倍的地震放大，而 SV（剪切）波可以产生高达 65 倍的放大。