Effect of Unsaturated Soil Properties on the Intensity-Duration Threshold for Rainfall Triggered Landslides

Authors : Melih Birhan KENANOĞLU, Mohammad AHMADIADLI, Nabi Kartal TOKER, Nejan HUVAJ

Pages : 9009-9027

Doi:10.18400/tekderg.414884

View : 6 | Download : 2

Publication Date : 2019-03-01

Article Type : Research Paper

Abstract :Rainfall triggered landslides are one of the most common natural hazards in many countries all around the world, as well as in Turkey. This study investigates the effect of unsaturated soil properties on landslide-triggering rainfall intensity-duration threshold. In addition to the time to failure, the suction insert ignore into journalissuearticles values(negative pore water pressure); distribution in the slope, the shape and depth of the failure surface are also evaluated. Properties of soil-water characteristic curve which affect the distribution of suction in the soil in response to changes in water content are varied in a parametric study. Effects of air entry value insert ignore into journalissuearticles values(relates to particle size);, de-saturation rate insert ignore into journalissuearticles values(relates to uniformity of particle size distribution);, saturated volumetric water content insert ignore into journalissuearticles values(relates to void ratio); and residual volumetric water content insert ignore into journalissuearticles values(relates to fines content and characteristics); are evaluated by determining the intensity-duration threshold numerically by carrying out infiltration and slope stability calculations. The variation of unsaturated soil properties is found to significantly alter the landslide mechanism insert ignore into journalissuearticles values(ranging from mere surface erosion to groundwater level rise in response to complete infiltration); and consequent intensity-duration thresholds for the same slope geometry. Among the parameters considered, air entry value appears to be the most influential parameter. The effects of the slope angle and initial moisture condition on threshold rainfall intensity-duration are also investigated. This study could be useful for creating the basis and mechanical understanding for future research on early warning systems.
Keywords : Unsaturated soil, rainfall triggered landslide, intensity duration threshold, soil water characteristic curve, suction