Unconfined Compressive Strength (UCS) and Compressibility Indices Predictions from Dynamic Cone Penetrometer Index (DCP) for Cohesive Soil in Kurdistan Region/Iraq

Abstract

Uniaxial Compressive Strength (UCS) and compressibility indices are essential tests for calculation of bearing capacity and settlement of cohesive soil in the foundation of building construction. These tests are time-consuming and demand significant effort. Therefore, the Dynamic Cone Penetrometer Index (DCP) can be utilized as an alternative method to predict UCS and compressibility indices such as compression index (Cc) and recompression index (Cr). In this study, the DCP is used to evaluate the UCS, Cc and Cr using the simple regression analysis. One hundred test pits were conducted in thirty-five locations, 150 DCP were tested at different depths and 150 samples were collected and tested for Natural water content, Dry density and Consolidation. The useful empirical equation between DCP and UCS was proposed. The obtained results prove the reliability of the proposed equations and for the first time, compressibility indices (Cc and Cr) were reasonably correlated with DCP. In addition, dry density of tested samples was studied and correlated with DCP.