Geotechnical Facets of Quaternary Sediments of Nubra Valley, Trans-Himalaya, India

Abstract

In the present study, attempts have been made to evaluate the geotechnical characteristics of Quaternary sediments of the Nubra Valley located in high-altitude Ladakh Himalaya to demarcate the active sediment (soil) zones and their bearing on natural hazards susceptibility and mitigation measures. The experimental works have been carried out on collected sediment (soils) samples from different locations and depths to determine their grain-size-sensitive parameters and geotechnical responses. The results reveal that the majority of uniformly graded sediments (soils) of size 0.02–2.0 mm fall in wide range of values of shear strengths, cohesions (c) and angle of internal frictions, which may be due to distinct variations in their bulk and dry densities, void ratios, and liquid and plastic limits. In view of evaluated geotechnical parameters, the sediment sequences of the valley are classified in normal and active sediment zones. The sediment layers of active zone exhibit a high rate of reduction in shear strengths and cohesions in comparison with normal zone due to higher liquid and plastic limits of sediments subjected to temperature-sensitive freezing and thawing actions and may responsible for slope instabilities, differential settlements and mass flow hazards. Hence, such sediment layers require serious and careful investigations for safe settlements and mitigation measures of natural hazards.