高地震烈度区堆积体边坡动力响应时程特征分析

考虑到在地震过程中,工程边坡的动安全系数最小值出现在某一瞬间,而用这个值评价边坡在地震荷载作用下的抗滑稳定性不合适宜。在简单分析地震荷载作用下边坡稳定性评价的主要方法及差异基础上,介绍了地震动力响应时程分析法的基本原理和计算过程,明确指出了边坡动力稳定分析时应注意的边界条件、材料参数等问题,建立了评价动力稳定性的有限元应力法表达式。基于地震动力时程反应,结合金安桥水电站库岸堆积体边坡工程,用动力有限元计算获得了边坡的动力响应在空间的变化规律(包括动应力和加速度等)和整体稳定性,计算成果合理地评价了其稳定性。

Analysis on Time History Dynamic Response of a Rockfall-type Slopeunder High Earthquake Intensity

The minimum stability safety factor occurs at one moment during the process of earthquake for a engineering slope.It is unsuitable to evaluate the dynamic stability of the actual engineering slope under the seismic load by using this value.In this paper the basic methods to evaluate the dynamic stability of the engineering slope under earthquake loads and their differences are analyzed first.The basic principles and computational process of seismic time-dependent dynamic response are introduced.The key problems,such as boundary conditions and material dynamic parameters,are pointed out.And the stability safety factor of the engineering slope based on FEM stress method is built up.Then,on the basis of seismic time-dependent dynamic analysis of a reservoir slope of Jinanqiao hydropower station,adopting the statistical analytical method,the dynamic extremum change(including the major stress extreme value,the minor stress extreme value,the relative acceleration extreme values on horizontal and vertical direction et al.)on the computational model are got.Then,adopting FEM stress method,the dynamic stability safety factor change are got also.According to the dynamic response feature and stability safety factor change,the dynamic stability of the example slope is evaluated reasonably.