Analysis of Residual Soil Properties on Slope: A Study in Dusun, Universiti Teknologi Malaysia, Johor

This study investigates the physical index properties and engineering properties of residual soil from the slope at Dusun Universiti Teknologi Malaysia (UTM) in Johor, Malaysia. The research was conducted to understand the soil characteristics that influence slope stability, given the frequent slope failures in the region. Both disturbed and undisturbed soil samples were collected and subjected to various laboratory tests. For physical index properties, tests included moisture content determination, specific gravity, particle size distribution (via sieve analysis and hydrometer), and Atterberg limits. Results showed that the soil has a moisture content of 31.7%, a specific gravity of 2.5, and is classified as sandy silt with high plasticity, as indicated by a plasticity index of 27.0%. The soil composition was found to be 20.4% clay, 44.7% silt, 30.1% sand, and 4.8% gravel. Engineering properties were assessed using the Consolidated Isotropic Undrained (CIU) triaxial tests on undisturbed samples. The tests were performed under different cell pressures (30, 60, and 80 kPa) to evaluate shear strength parameters, specifically the effective cohesion (c') and effective friction angle (phi'). The results indicated that the soil has an effective cohesion of 13.0 kPa and an effective friction angle of 27.0 & ring; The study concludes that the residual soil in the study area exhibits significant plasticity and strength, which are critical factors for slope stability. These findings provide essential insights into the behavior of residual soils under varying conditions, contributing to safer geotechnical infrastructure development in slope-prone areas.