Comparative Analysis of Shear Strength of Ravi, Chenab, and Lawrencepur Sands: The Effect of Moisture Content and Degree of Saturation

Abstract

The recent unpredicted and unprecedented rainfall events under climatic scenarios emphasized the effect of varied moisture content and fluctuating saturation levels on the mechanical properties of indigenous construction materials. This study investigates the influence of moisture content and degree of saturation on the angle of internal friction of three locally available sandy soils: Ravi, Chenab, and Lawrencepur sand. These sands are widely used in the construction industry due to their availability and cost-effectiveness in Pakistan. However, the mechanical behavior of these sands under varying moisture conditions remains underexplored, particularly concerning their shear strength characteristics. The study employed a comprehensive laboratory testing program, including index tests and direct shear tests (DSTs), to evaluate the effect of moisture content and degree of saturation on the angle of internal friction. The results affirmed that the angle of internal friction is highest i.e. , , and of Ravi, Chenab, and Lawrencepur sand respectively, at the optimum moisture content (OMC), with a significant reduction observed when moisture content deviates from the OMC. Furthermore, the angle of internal friction decreases with an increasing degree of saturation, with Lawrencepur sand exhibiting the highest value of 35^o across all saturation conditions. These findings provide crucial insights for optimizing the use of local sands in construction projects, especially in regions with variable moisture conditions. The study concludes that Lawrencepur sand, due to its higher dry density i.e. 17.9 kN/m³.and lower void ratio i.e. 0.68 is the most suitable for construction compared to Ravi and Chenab sands.