Research Projects

Landslides are common natural hazards in India, with 3285 of 5318 non-seismic landslides triggered by rainfall from 2014-2017. The upper layer of geo-mass, which contains residual soil sands, clays, and gravel, is a challenging area for characterization due to its various partial sizes. Conventional shear strength testing setups are limited by the particle size gradation of the upper layer, which can be six times the maximum size of the particle. Researchers have used large-scale triaxial and direct shear setups to study the particle size's effect on shear strength parameters for rockfill dams. Scaling-down techniques, such as scalping and parallel scaling-down, have been widely used in laboratories. However, discrepancies between scale-down specimen and actual specimen test results have been found, emphasizing the importance of large-scale testing. Most studies focus on the effect of maximum particle size, but partial saturation is not examined in detail for materials like natural slopes. The current proposal addresses this gap by conducting large-scale direct shear tests on the soil-boulder matrix, varying grain size distribution and water content. This will enable the development of a mathematical method to quantify the critical rainfall intensities and durations required to trigger a landslide for an early warning system.