Piezocone Screening Approach for Regular, Organic, and Sensitive Soft Clays

It is important to identify the type of clay encountered during cone penetration testing (CPT), especially the distinction between regular, organic, or sensitive clay, as this can significantly impact the construction technique, foundation selection, and choice of ground modification method for a given project. Identification of clay type is often handled using CPT soil behavioral type charts; however, these can be incorrect and/or misclassify the clay category. As either a supplemental or alternative approach, a simple screening using three expressions for evaluating preconsolidation stress (σp′) that depend on net cone resistance, excess pore pressure, and effective cone resistance can be implemented. Several case studies from regular, organic, and sensitive clays are presented to illustrate the method and corresponding interpretation of σp′ profiles.