Use Of The Static Cone Penetration Test For The Classification Of Some Local Soils

Abstract

The present study was carried out to update and extend the application of a previous method developed for the classification of local soils on the basis of Cone Penetration Test (CPT) data. The studied soil types covered areas in six different states in the country including Khartoum and Gezira States in Central Sudan, Jonglei and Upper Nile States in Southern Sudan, Greater Kordofan State in Western Sudan and Gedaref in Eastern Sudan. Widely different soil types were covered in this study and were broadly classified to fine grained soils and coarse grained soils. The fine grained soils comprised the main groups silty soils and clayey soils which includes the subgroups silts of low to high compressibility and clays of low to high plasticity respectively. The coarse grained soils comprised the main group sandy soils which includes the sub groups clean sands, silty sands and clayey sands. The soil types were classified according to the Unified Soil Classification System (USCS). Two CPT machines with 100 to 200 KN thrust capacity and equipped with a standard mechanical adhesion jacket cone were used for obtaining the CPT data required for the present study. CPT data were analysed by “Discriminant Analysis”, statistical approach to derive different discriminant functions for each soil group considered in this study. A method of soil classification was developed based on a correlation between soil type and CPT data for variety of local soils. Full description of the developed method and the steps involved in its application for interested researchers and engineers are presented in chapter 4. It was concluded from the study that the CPT is a reliable method, which may be used to classify local soils with fairly high degree of accuracy.