A COMPARISON OF TECHNIQUES FOR IDENTIFYING SOIL DYNAMIC PROPERTIES
The dynamic properties of soil, expecially the damping raio, are very important parameters in the calculation of underground structures response due to earthquake excitation. In current practice, however, the damping ratio is often determined by static experiment that may not reflect the evolution of damping ratio with the vibration amplitude and frequency. In this connection,the viscous damping ratio of silty clay and its fundamental frequency in a series free-field shaking table test are identified in this paper by three commonly used techniques, i.e.the stochastic subspace identification (SSI), frequency domain decomposition (FDD) and empirical mode decomposition (EMD) plus Hilbert transform (HT). The applicability of the three methods are verified and identification results are discussed in items of effect of input type, selection of calculating parameters in HHT method and discrepancies of results identified by the three methods. It is found from this study that the HHT method can be applied for large damping value case provided that special measure is taken in fitting the Hilbert amplitude curve. The results obtained in this study implies that for strong nonlinear status of soil a time-varying damping ratio model might be more proper than linear equivalent damping ratio model.
Shaking table test Empirical mode decomposition Hilbert transform Stochastic subspace iteration Frequency domain decomposition
Jun Chen Guan-Yu Zhao Xiao-Yu Qi Jie Li
Department of Building Engineering, Tongji University, Shanghai 200092, P.R. China State Key Laborat Department of Building Engineering, Tongji University, Shanghai 200092, P.R. China
国际会议
第十届国际结构工程青年学者研讨会(The Tenth International Symposium on Structural Engineering for Young Experts)
长沙
英文
1536-1541
2008-10-19（万方平台首次上网日期，不代表论文的发表时间）