Determination of undrained shear strength and modulus of elasticity of fine grained soils from SPT in Islamabad, Pakistan

Abstract

Many researchers report that the Standard Penetration Test (SPT) is not standard as the name implies. However, the test is relatively simple to conduct, produces an indicator of soil resistance (N-value) and provides a soil sample for visual identification and laboratory testing therefore, maintains its popularity with geotechnical engineers worldwide. Due to unavailability of equipment, financial limitations, time limitations and especially when limited data is available use of correlations to determine different parameters prove to be helpful. A number of correlations of N-value, with parameters as relative density, friction angle, allowable bearing capacity, pile skin friction and many others, have been developed. This study is carried out to develop correlation of SPT with undrained shear strength (Su) and soil modulus of elasticity of fine grained soil in Islamabad, Pakistan. It is tried to conclude how corrected and uncorrected values of SPT influence the parameters to be determined. This study answers the question of SPT applicability in fine grained soils. This work also addresses the correlation between plasticity index and undrained shear strength (Su). All the correlations are developed using Microsoft Excel 2013 with a focus on the statistics.