Shaking table test study on the vertical seismic behavior for the layered rock slopes
LIU Han-xiang1, XU Qiang1, Zou Wei2, XU Hong-biao3
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1. State Key Laboratory of Geo-Hazard Prevention and Geo-Environment Protection, Chengdu University of Technology, Chengdu , Sichuan 610059; 2. China Railway Eryuan Engineering Group Company, Sichuan 610031;3. Sichuan Provincial Communications Department Highway Planning Survey Design Research Insitute, Sichuan 610041
A large scale shaking table test was conducted on two 1:100 scaled slopes, which have the lithological combinations of hardness-upward or softness-upward formed broadly in 2008 ‘5.12’ Wenchuan Earthquake areas, Sichuan Province, China. Ruled by Buckingham π’ s similitude theorem, waves of different kinds, directions and amplitudes were inputted at the base of models. Modal test result based on FEM and instrumental records shows that the model box has enough rigidity without resonance with model slopes and amplification itself during shaking. With the more and more importance of vertical ground motion and its lack of test study, in this paper, based on the recorded data, the peak vertical accelerations and their amplification factors along different elevations were mapped under incremental excitation levels, when subjected to sine waves especially to real waves scaled from Wenchuan Earthquake waves. Results show: (1) the amplification effect occurs in vertical components with increasing elevations, however, the amplifying speed in the upper part is basically smaller than that in the lower part of model slopes, though the maximum amplification occurs in the upper part; (2) when excited by Wenchuan earthquake waves, the amplification factors in the upper part decrease gradually to a final stable state while those in the lower part has little change with increasing excitation intensity, which indicates the attenuation in amplification effect; (3) responses under earthquake waves in combinational directions are stronger than those in vertical direction only, but the difference in excitation directions has little effect on the change laws of vertical accelerations. (4) Responses in the softness-upward model slope are stronger than those in the hardness-upward model slopes. Results provide a good understanding of the damage caused by vertical component of earthquake, and also a guide to select the more reasonable vertical seismic coefficient during dynamic slope stability calculation.
LIU Han-xiang;XU Qiang;Zou Wei;XU Hong-biao.
Shaking table test study on the vertical seismic behavior for the layered rock slopes[J]. Journal of Vibration and Shock, 2012, 31(22): 13-19