Investigation of the effects of different layering characteristics on the response of semi-sine hills

Abstract

Investigating the phenomenon of topographic amplification and the seismic response of the site is an important issue that has already attracted the attention of many researchers. The studies and researches conducted in the field of topographical effects and also the phenomenon of the amplification of earthquake waves in passing through surface layers have shown that topography has a great impact on the amount of damage caused by earthquakes. The local topographic characteristics amplify the strong movements of the ground during an earthquake and ultimately cause great damages. In this article, the effects of a site (take, for example, one of the most common topographical forms in nature, such as a semi-sinusoidal hill) on the seismic response of the earth’s surface subjected to vertically propagating shear vertical (SV) waves have been studied using FLAC 2D, a two-dimensional finite-difference program. In the numerical modeling, the elastic linear behavior has been used. In this regard, in order to investigate the effects of layering on the response of semi-sine hills, two-layered and three-layered hills with different layering characteristics and thicknesses are considered the basis of this article. In this research, the effect of soil characteristics, layering thickness, and the position of the loose layer has been investigated. From the obtained results, it can be concluded that the characteristics and thickness of the layering and the position of the loose layer have effects on the general trend of amplification on top of the hills and de-amplification near the toe of hills in response to horizontal motion for acceleration, velocity, and displacement components.