降雨条件下非饱和粉质航道岸坡稳定性数值分析

Numerical analysis on saturated silty channel bank slopes stability under rainfall condition

降雨条件下粉质岸坡稳定性问题是工程技术人员面临的重要问题之一。针对苏北某船闸上游引航道护岸粉质土体边坡,建立降雨条件下考虑雨水入渗和坡体塑性变形耦合作用的非饱和粉质土体岸坡稳定性分析数值模型,探讨不同降雨强度下非饱和土质岸坡的饱和度、浸润线、基质吸力、安全系数及坡比等因素对岸坡稳定性的影响规律。结果表明:降雨导致非饱和粉质土体岸坡最危险滑裂面迅速上移,50mmd的降雨强度将导致最危险滑裂面平均上移约2.4m,每增加10mmd降雨量,岸坡浸润线水头升高约50cm;岸坡安全系数随降雨强度呈线性下降,降雨过程中安全系数下降的幅度随坡比的增大而增大。

The stability of silty bank slope under rainfall is one of the most important problems faced by engineers.Against the silty bank slope of the upper approach channel of some ship lock in North Jiangsu,the numerical model for the stability analysis of unsaturated silty bank slope is established,which considers the coupling effect of rainfall infiltration and slope plastic deformation.The effects of saturation,saturation line,matrix suction,safety factor and slope ratio on the stability of unsaturated soil bank slope under different rainfall intensity are discussed.It shows that the most dangerous slip surface of the unsaturated silty bank slope caused by rainfall increases quickly,and the rainfall intensity of 50 mm d will cause the most dangerous slip surface to move up about 2.4 m.The head of the slope immersion line is raised by about 50 cm with every 10 mm d increase of rainfall.It also shows that the safety factor of the bank slope decreases linearly with the rainfall intensity,and the decrease of safety factor during the rainfall process increases with the increase of the breaking ratio.