Shear Strength Characteristics of Frozen Fine Sands under Direct Shear Testing Conditions

Abstract

Geomechanical properties such as shear strength, stiffness, and compressibility of soils subjected to subzero temperatures are of utmost importance for executing various projects related to infrastructure development and harnessing sustainable energy in cold regions. In this context, earlier researchers have employed sophisticated equipment such as triaxial equipment to establish these properties of the fine sands, which turns out to be quite expensive. To overcome this, a suitably modified low-cost temperature-controlled direct shear box apparatus has been fabricated. The setup’s utility and efficacy have been demonstrated by investigating the influence of the volumetric ice content, rate of shearing, and vertical stress on shear strength characteristics of the fine sands in their frozen state. In addition, the effect of (1) postfreezing shearing and the (2) confined-state freezing and shearing, the two methodologies that are generally adopted by earlier researchers on shear strength characteristics, have also been studied. Based on the extensive testing, it has been demonstrated that for frozen fine sands, the cohesion, secant modulus, and dilation angle increase with an increase in the rate of shearing and the volumetric ice content, and these variations can be expressed by power laws.