Influence of concave sedimentary soil layers in Suzhou city on characteristics of seismic response
1. Faculty of Civil Engineering and Mechanics, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2. Institute of Geotechnical Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009, China
Abstract：For the sedimentary sites of Suzhou urban depression with non-uniform distribution of soil layers, a large-scale two-dimensional(2D) FE analytical model for concave sedimentary soil layers in Suzhou city was established based on the computing cluster platform of ABAQUS. The viscoelastic artificial boundary was proposed for simulating the boundary problem of infinite field, and the main characteristics of peak acceleration, peak displacement and spectrum were analyzed. The results show that the seismic response of concave sedimentary site presents great spatial difference, and the amplification effect of peak ground acceleration is obvious in some specific positions. The sensitive periods of the urban site of Suzhou city is about 0.20 to 0.70 s. Compared with the horizontal uniform site, the acceleration response spectrum of the concave sedimentary site changes significantly along the horizontal direction, and the corresponding spectrum peak shifts towards the long period direction as it comes close to the ground surface. Because the seismic waves are focused and amplified in some local areas, the PGA values in the concave sedimentary site show ups and downs along the direction of depth. The PGD values along the horizontal direction show non-monotone decreasing with the increasing of soil depth, which is related to the spectral characteristics of input ground motions. To some extent, the large-scale 2D FE model can reflect the effects of non-uniform distribution of soil layers on seismic wave propagation.
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2019, Vol. 40 
