Integration of SPT (N-value), mackintosh probe (M-value) and resistivity values for soft soil assessment

Abstract

2-D resistivity method has been used in association with Mackintosh probe and Standard Penetration Test (SPT) to investigate the ground properties at Universiti Sains Malaysia, Pulau Pinang. The purpose of this study was to determine the resistivity value of the subsurface material together with N-value and M-value of the particular location. The study also aimed to evaluate whether there is any correlation could be made by the parameters measured. Borehole record revealed that two types of soil exist up to 13 m; loose sand and stiff sandy silt. The loose sand recorded N-value of 8 and M-value of 170 having resistivity value of 790 Ohm.m. On the other hand, stiff sandy silt recorded N-value of 9-11, M-value of 135-170 and showing resistivity value of 415-785 Ohm.m. The results showed no clear relation between those geotechnical strength parameters with the resistivity imaging result. It is due to non-existence of distinctive differences in the electrical conductivity of the mentioned ground material when they are in the low strength bracket. However, the resistivity result suggested the presence of higher resistance material that is dry loose sand. The resistivity result was able to detect the water saturated zone near the ground surface, which showed low N-value and M-value.