摘要
针对倾斜边坡上覆层状沉积土层场地,开展层状沉积谷地内地震响应机理及特征研究.通过设置黏弹性人工边界和等效节点力的方法实现地震动输入,考虑倾斜基岩和沉积层序的变化对谷地地表响应的影响,基于显式有限元方法分析了谷地内地震动的传播过程.结果表明:不同沉积层序下地表地震动响应存在显著差异,正常沉积时,谷地内地表水平加速度时程峰值最大,对应的反应谱峰值周期最小;对于地表位移响应,低频段内非正常沉积(即软夹层沉积和逆序沉积)情况下更为显著,中高频段内正常沉积情况下更加明显;软夹层沉积谷地能过滤一部分中高频段地震波,表现出一定程度的“隔震”效果;输入不同频率成分的地震动时,逆序沉积情形下表现出谷地边缘附近区域比较安全;实际工程场地中,应综合考虑倾斜基岩、沉积层序及地震动特性等对谷地内地震响应的影响.
The seismic response mechanism and characteristics of layered sedimentary valleys on inclined slopes were investigated.By setting viscoelastic artificial boundary and equivalent node force,the seismic input was realized.Considering the change of inclined bedrock and sedimentary sequence,the propagation process of seismic wave in the valley was simulated and analyzed based on the finite element method.The results show that there are significant differences in ground motion response under different sedimentary sequences.For normal sedimentation case,the peak time history of surface horizontal acceleration in the valley is the highest,and the corresponding peak period of the response spectrum is the smallest.For the surface displacement response,the abnormal depositions of soft interlayer deposition and reverse deposition in the low frequency band show more obvious response,while the normal deposition shows significant response in the middle and high frequency bands.Soft interlayer sedimentary valleys can filter out some high frequency seismic waves and show a certain degree of "seismic isolation" effect.When the seismic waves with different frequency components are input,the reverse sedimentation situation shows that the area near the edge of the valley is relatively safe.The effects of inclined bedrock surfaces,sedimentary sequences and seismic characteristics on the seismic response of valleys should be comprehensively considered in the actual engineering sites.
作者
金丹丹
马成祥
张锐
JIN Dandan;MA Chengxiang;ZHANG Rui(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang,Jiangsu 212013,China)
出处
《江苏大学学报(自然科学版)》
北大核心
2025年第2期240-248,共9页
Journal of Jiangsu University:Natural Science Edition
基金
国家自然科学基金资助面上项目(51978317)
中国地震局地震工程与工程振动重点实验室开放研究专项(2021D19)。
关键词
沉积谷地
地震响应
倾斜基岩
沉积层序
显式有限元方法
sedimentary valley
seismic response
inclined bedrock
sedimentary sequence
explicit finite element method
