Geotechnical Attributes of Active Sediments and its Prospective in Hazards Susceptibility and Mitigation Measures: A Study on Soils from Leh Valley, Ladakh Himalaya, India

Abstract

In the present study, attempts have been made to evaluate the geotechnical characteristics of Quaternary sediments from high altitude Ladakh Himalaya to demarcate the active sediment (soil) for its bearing on natural hazards susceptibility and mitigation measures. The experimental works have been carried out on collected sediments (soils) from different locations and depths during year 2014 for determination of grain size sensitive parameters and geotechnical attributes as per American Society for Testing and Materials standard and empirical relationships. The results reveal that the majority of uniformly graded sediments (soils) of size 0.02–2.0 mm exhibit wide range of shear, cohesions (c) and angle of internal frictions may be due to difference in their bulk and dry densities, void ratios, liquid limit, plastic limit and liquid index. Thus, the sediments of Leh Valley can be classified in normal sediment (soil) unit and normally active sediment (soil) unit. The normally active unit exhibits lower shear strengths and cohesions in comparison to normal unit due to higher liquid and plastic limits of sediment subjected to temperature sensitive freezing and thawing actions. The active sediment (soil) unit has been found more prone to slope instabilities, differential settlements and mass flow hazards, hence requires special care during developments and mitigation measures.