Rainfall threshold to trigger landslides in unsaturated soils: A laboratory model study

Rainfall triggered landslides are common natural hazards with significant consequences all over the world. In this study, laboratory model tests are conducted which aims to obtain the rainfall intensity-duration threshold to trigger landslides in a slope composed of unsaturated soil in a flume setup. Sixteen laboratory model tests are conducted to obtain the rainfall intensityduration threshold. Some of the conclusions in this study are: (1) rainfall intensity-duration (I-D) thresholds that would trigger a landslide can be obtained physically in the laboratory, (2) the shape of the I-D threshold plot is demonstrated to be a partly-linear relation in log-log plot for the soil used in this study, (3) below a certain rainfall intensity (15 mm/hour in this study) landslides are not triggered in unsaturated soil used in this study, (4) it is observed that shallow landslides are not triggered by any rainfall when the soil is dense