Quantification of soil non-linearity based on simulation

Recent earthquake studies have demonstrated that non-linear behavior of sof t soil can be significant compared to other effects affecting seismic motio n. Therefore, the question is to know when sediment non-linearity is a firs t-order effect and when it is not. In this study, we propose a method for q uantifying non-linear effects based on simulations. An elasto-plastic model is used to simulate the behavior of four materials (sands and clays). For each computation, the non-linearity is quantified by the use of a 'non-line ar parameter' and compared to four non-linearity indicators. These computat ions suggest that the efficiency of an indicator depends on the nature of t he soil underlying the recorder and that the most efficient indicator shoul d be based on the high frequencies content rather than on the resonant freq uency changes. (C) 2001 Elsevier Science Ltd. All rights reserved.