Experimental Investigations on Rainfall-Induced Landslides: Fid-Bau Portal

Experimental Investigations on Rainfall-Induced Landslides

Kumar, Ganesh / Sarkar, Shantanu / Gupta, Mayank / Devi, Priyanka

In recent times, the occurrence of natural hazards in India and around the world is increasing day by day. Landslides are one of the most destructive natural phenomena which not only cause extensive damages to the structures but also result in loss of lives. Among various factors, rainfall is one of the most important triggering factors for inducing landslides. In most of the time during rainfall, due to infiltration of water into the soil, the pore water pressure increases which destabilizes the slope resulting in landslide. This paper presents detailed laboratory experimental studies on the behaviour of rainfall-induced landslides. For experimental testing, indigenous test system has been developed at CSIR-CBRI for investigating rainfall-induced landslide. The system comprises a tilted channel and artificial rainfall simulator system. The arrangement of rainfall simulator can able to reproduce landslide triggering under varying intensities of rainfall with uniform rain distribution. For the present study, a model slope was created with the landslide debris soil material brought from the Lesser Himalayan region of Uttarakhand State. After soil characterization, rainfall experiments were conducted on the equivalent slope model using artificial rainfall simulator system. The rainfall experiments were performed with rainfall intensity equivalent to some reported high rainfall intensity experienced in the past in the Himalayan region. During rainfall experiments, the increase in soil moisture and soil movement was monitored continuously. The time at which slope failure initiated was observed and corresponding soil moisture and slope movement pattern was evaluated. Finally, the mechanism of slope failure was analysed and possible slope protection measures were suggested.