基于竖向台阵的土体小应变阻尼比随深度变化规律研究OA北大核心

Currently,the small-strain damping of soil used in seismic site response analysis is general-ly determined based on laboratory tests.However,since laboratory tests can only represent material damping of soil,they cannot reflect the scattering effects caused by spatial variability of the site dur-ing seismic wave propagation.Therefore,directly using the small-strain damping obtained from labo-ratory tests often leads to a significant overestimation of the predicted site amplification.To address this issue,this study selected four vertical seismic arrays from the United States and Europe.First,the in-situ shear wave velocity structures of these sites were extracted from the seismic data using the seismic interferometry method.Then,the in-situ small-strain damping ratio structures were inverted using the simulated annealing algorithm,and the variation of the small-strain damping ratio of the soil with depth was discussed.Finally,the performance of the uniform damping assumption and the non-uniform damping assumption in reproducing and predicting seismic site response was compared.The results showed that the in-situ soil dynamic parameters inverted using seismic interferometry and the simulated annealing algorithm could well reproduce and predict the seismic site response under small-strain conditions.Meanwhile,the in-situ small-strain damping ratio profile did not exhibit a clear variation pattern with depth.Moreover,in most cases,whether the uniform damping assump-tion was adopted had almost no effect on the simulated values of surface acceleration response spec-tra.Therefore,the uniform damping assumption could be directly adopted in seismic site response analysis under normal circumstances,without the need to consider the variation of damping ratio with depth.