Investigation of Shear Strength of Frozen Sand

Abstract

In the sphere of civil engineering today, research is pivotal to mitigate potential hazards in lieu of Global warming. Glaciers are heaving owing to numerous factors among which our study of interest is soil –interface frictional angle. Moreover, effective normal stress is a cause for movement of glacier as the resisting shear force is dependent upon normal effective stress. Permafrost is the region where ground temperatures remain below 0°C continuously for two years or more. China Pakistan Economic Corridor proposes a Bridge to be built in proximity to Shispar glacier in Aliabad Hunza for which lab tests are a pre-requisite since, field investigations are expensive to conduct and assess feasibility of soil under frozen conditions. Frozen soil exhibits a peculiar behavior under load which is variable according to temperature, specific gravity, density, and moisture content. A lab prototype has been developed by our group for the investigation of shear strength of frozen sand. Direct shear test was conducted to obtain shear strength through the peak and critical friction angle obtained from the experiment under two different scenarios. Dilantancy and shear strength behavior of frozen as well as unfrozen sand was studied. Results revealed that melting ice leads to transformation in soil structure which consequently, renders low strength.