地震作用下边坡安全系数时程计算及参数研究  

Calculation method and parameter research for time-history of factor of safety of slopes subjected to seismic load

作　　者：康永君[1] 杨军[1] 宋二祥[1] 

机构地区：[1]清华大学土木工程系,清华大学土木工程安全与耐久教育部重点实验室,北京100084

出　　处：《岩土力学》2011年第1期261-268,共8页Rock and Soil Mechanics

基　　金：国家高技术研究发展计划(863计划,No.2007AA11Z113);国家自然科学基金(No.50908123)

摘　　要：提出了一种计算地震作用下边坡动力安全系数时程的方法,该方法以动力有限元时程分析得到应力场,再使用遗传算法搜索每个时刻下的临界滑裂面,进而确定其安全系数,从而得到边坡在动力作用下的安全系数时程,物理意义明确。通过在基岩输入不同周期的正弦波加速度,研究了动力作用周期对安全系数时程的影响,发现相同加速度幅值下周期越大安全系数越小,安全性越低。与边坡自振周期和振型比对后发现,地震波周期与边坡自振周期耦合引起的动力响应增大,不仅与周期耦合相关,还与相应的自振振型相关,只有与以坡体本身振动为主的振型耦合时,才会发生明显的动力响应增大,相应的安全系数明显降低。A method to calculate the time-history of safety factor of slopes subjected to seismic load is given. At every moment, the stress field got from dynamic finite element analysis, and the critical slip surface is searched by genetic algorithm. So, the time-history of factor of safety is derived and has definite physical meaning. By inputing sine wave acceleration with different periods from the bed rock, the relation between the period and the factor of safety is studied. The results show that as the period of input becomes longer, the factor of safety becomes lower. The natural period and mode shape of the slope are investigated; and one can find the amplification of dynamic response cause by the coupling of the load period and the natural period of slope not only depends on the coupling of the period, but also the mode shape of the slope. Only when the mode shape is a vibration of the slope itself, the dynamic response will be amplified and the factor of safety will decrease.

关 键 词：边坡稳定 动力 安全系数 时程 遗传算法 

分 类 号：TU435[建筑科学—岩土工程]