Shear Strength Evaluation of Silt-Clay Soil under Uni-Axial Compression

Abstract

Effect of different moisture content and applied pressure to soil shear strength parameters are evaluated. Silt-Clay soil from Ngemplak, Kalikotes, Klaten Regency becomes the subject of the experiment. The research was conducted using a simulation in the laboratory to determine the relationship between water content and soil pressure. The expected values are the pressure that arises and the shear strength of the soil when using four water constructions of 20%, 25%, 30%, and 35%. For each variation of moisture content, three different pressure in the form of uni-axial compression that considered based on the different energy given by equipment used to do compaction will affect the soil density. The applied pressure used is 1.5 kN, 2.5 kN, and 3.5 kN. The result showed that moisture content having a great impact on soil shear strength parameter. The cohesion of soil decreases due to an increase in water content. The friction angle works in linear conditions with moisture content but decreases at the value of 35% water content. The best-fitted distribution for the relationship between soil shear strength and moisture content is polynomial order two. Follow the equation for 1.5 kN applied pressure is y = -0.0036x 2 + 0.2236x - 2.4898, for 2.5 kN applied pressure the equation is y = -0.0025x 2 + 0.1545x-1.3383, and for 3.k kN applied pressure the equation is y = -0.0022x 2 + 0.1357x - 1.0344.