Effective Shear Strength Parameters of Remoulded Residual Soil : Geotechnical and Strength Properties Investigations of Tropical Residual Soil by Triaxial Compression Tests

Lots of soil's geotechnical characteristics involved in the construction problems. Soil will eventually reach failure and deforming excessively when it is subjected to gradually increasing load. This failure is related to the shear strength which is considered as one of the most important engineering properties of the soil. This research focused on comparison of effective shear strength parameters (c', ') that obtained from both Consolidated Undrain (CU) and Consolidated Drain(CD) triaxial tests for remoulded residual soil (silt). This study presents a reduction factor that helps to evaluate the effective internal friction angle of CD test from the results of CU triaxial test. The reduction factor is in the range of 0.89 to 0.92 that came as a result of this study to samples of residual soil with different initial water content. The initial water content had an influence in triaxial compression testing on the soil strength; soil effective cohesion became higher in the range of (11% up to 29 %) when initial water content changed from 53% to 43%, and soil effective friction angle would increase by (3% up to 6%).