The Effect of Dry Density on Shear Strength Parameters of Ravi, Chenab and Lawrencepur Sand in Dry and Saturated Conditions

Soil is the soul material for any civil engineering structure. In general, there are two types of soil; cohesive soil and silty sand. Silty sand is mineral soil that exhibits granular characteristics in which the grains remain separate from each other and do not hold together in aggregates of particles. Silty Sand may also be called cohesion less soils or granular soils. In the soil classification system used by soil scientists, silty sand include sand, loamy sand, and possibly sandy loam if the silt-sized particles are non-plastic or non-sticky. In designing civil engineering structures, the determination of shear strength parameters is very important. Some of the major problems faced in civil engineering structures are foundation failures, slope failures, and retaining wall failures. These problems can be solved by the selection of actual values for shear strength parameters (c &amp; ɸ) and should be based on derived values resulting from laboratory and field tests. <br><br>The methodology includes a collection of sand samples from the site. After the collection of sand samples, the sand samples were preserved and transported to determine the in-situ moisture content using the Oven-drying method. The gradation of sand samples was determined by performing Sieve analysis on samples and results were compared to find the relation of gradation and dry density. The standard &amp; modified proctor test was performed to find maximum dry density and optimum moisture content. The Direct shear test was performed in dry &amp; saturated conditions to determine shear strength parameters. <br><br>The major findings include the moisture content of sand samples as 6.5% in Ravi sand, 8.7% in Chenab sand, and 7.8% in Lawrencepur sand by the Oven drying method. By sieve analysis, the values of D10, D30, and D60 are 0.20mm, 0.16mm, and 0.11mm for Ravi sand. Similarly, for Chenab Sand, the values are 0.21mm, 0.17mm, and 0.13mm, and for Lawrencepur Sand are 0.29mm, 0.20mm, and 0.16mm respectively. The loose density of Ravi, Chenab &amp; Lawrencepur Sand is 1.29 g/cc, 1.28 g/cc &amp; 1.42 g/cc respectively. In Standard Proctor Test, for Ravi sand, Chenab &amp; Lawrencepur sand, the MDD is 1.71 g/cc, 1.68 g/cc &amp; 1.87 g/cc and OMC is 15.3%, 15.9% &amp; 15.1% respectively. In Modified Proctor Test, for Ravi sand, Chenab &amp; Lawrencepur sand, the MDD is 1.76 g/cc, 1.71 g/cc &amp; 1.91 g/cc and OMC is 15.1%, 16.5% &amp; 15.0% respectively. In dry conditions as, the Ravi sand has a Cohesion of 2.93 kPa and an angle of internal friction of 31.71o. The Chenab sand has a Cohesion of 2.40 kPa and an angle of internal friction of 37.65o. And, the Lawrencepur sand has a Cohesion of 1.32 kPa and an angle of internal friction of 40.27o. In saturated conditions, the Ravi sand has a Cohesion of 2.28 kPa and an angle of internal friction of 27.37o. The Chenab sand has a Cohesion of 2.50 kPa and an angle of internal friction of 42.76o. And, the Lawrencepur sand has a Cohesion of 1.93 kPa and an angle of internal friction of 38.26o.<br>For future recommendations, if there is sandy soil encountered within the shear zone under the foundation, the bearing capacity should be based on direct shear values “c &amp; ɸ” and Standard Penetration Test SPT (N) values.