Surface Drainage to Minimize Rain-Induced Slope Failures in Unsaturated Residual Soil
Residual soils are formed in situ due to weathering of rocks and are inherited with highly non uniform characteristics which make their behavior quite complex.Most of the Sri Lankan slopes are made of residual soils and ground water table is at a deeper level during the dry season.Thus the upper part of the slope is in an unsaturated state Strength of an unsaturated soil is greatly enhanced by matric suction.Rainfall leads to a reduction of matric suction and development of perched water table conditions.Using an infiltration model, the variation of the pore pressure regime during a rainfall event, the effect of berm drains and surface protection vegetation were studied.The pore water pressure regimes were incorporated into a stability analysis to assess the safety margins during a prolonged rainfall event.The typical longitudinal sections with different geological conditions from the southern transport development project in Sri Lankan were idealized to three simple ones.This analysis was carried out for 5 days uniform rainfall with intensities of 5mm/hr and 2omm/hr.The presented study showed that the introduction of a sealed berm layer and a protecting vegetation layer on slopes can effectively control the infiltration and minimize the reduction of safety margins during a prolonged rainfall.This would be a very cost-effective approach to improve the residual soil slope stability.
slope stability unsaturated soil matric suction infiltration vegetation
S.A.S.Kulathilaka L.M.Kumara
University of Moratuwa, Department of Civil Engineering, Moratuwa, Sri Lanka
国际会议
World Landslide Forum 3(第三届世界滑坡论坛)
北京
英文
518-523
2014-06-02（万方平台首次上网日期，不代表论文的发表时间）