考虑降雨与坡脚采石影响的海岛岩质边坡稳定性分析

Stability of Island Rock Slope under Rainfall and Toe Quarrying

基于海岛岩质边坡实际监测位移,利用有限元强度折减法,研究降雨与坡脚采石对海岛岩质边坡稳定性的影响.在降雨因素影响下,采用等效折减的办法,即以监测位移统计为依据的"日降雨量与日位移增量关系"和以有限元计算结果为依据的"折减系数与位移关系",以位移为中间变量,把日降雨量引起的边坡位移增量等同于因边坡强度参数降低引起的位移增量,从而建立了日降雨量与边坡强度等效折减系数的对应关系,提出了降雨导致边坡失稳的预警值.在坡脚采石因素的影响下,对坡脚开挖进行了11种方案的计算,通过对计算结果的对比分析,得出坡脚采石量对安全系数的影响程度与规律,提出了坡脚开挖对海岛斜坡稳定性的预警值.

Based on the actual monitoring displacement of island rock slope and by using the finite element strength reduction method, the effects of rainfall and toe quarrying on the stability of island rock slope have been studied. An equivalent reduction approach is proposed to consider the influence of rainfall on slope stability. The kernel of this method is that the slope displacement increment caused by rainfall is equal to the displacement increment caused by the reduction of slope strength parameters. Based on the relationship between daily rainfall and daily incremental displacement and the relationship between reduction factor and displacement, taking the displacement as the intermediate variable, the corresponding relationship between daily rainfall intensity and slope equivalent reduction coefficient is established and early warning values of slope instability due to rainfall are proposed. For the influence of toe quarrying, eleven calculation schemes are presented. Based on the analysis of computing result, the influence of toe quarrying on the safety factor has been obtained, and the early warning value of toe excavation on stability of island slope are also proposed.