Landslide occurrences in Himalayan residual soil: a review

Abstract

The present paper is a preliminary review of frequent landslides in the Himalayan residual soil due to extensive weathering. The geotechnical characteristics and engineering behaviour of residual soil depend mainly on the genesis and degree of weathering, which in turn depend on lithology, mineralogy, hydrology, stratigraphy, and climatic condition. Critical advances in laboratory and field testing are highlighted, their application to modelling of residual soil behaviour under different boundary conditions has been discussed. The behaviour of residual soil is highly influenced by the coupled interaction between water and clay content. Potential future advances which can provide new insights into the behaviour of unsaturated clayey residual soil after precipitation are identified. It has been concluded that the hydrology, followed by the clay mineralogy, plays a prominent role in the stability of soil slope. These two factors act concurrently to render the slope unstable after rainfall. Further work is needed to integrate these two crucial factors while modelling the unsaturated residual slope to increase the accuracy of predictions and assessments of its engineering behaviour. © 2021, Wadia Institute of Himalayan Geology. All rights reserved.