Estimating in-situ undrained shear strength and stress history of clays via water content

Liquidity index has been long believed to correlate to design parameters of clays such as undrained shear strength, sensitivity, overconsolidation ratio, etc. Such correlations are important because liquidity index is usually the most basic and available index from site investigation information. This study compiles a large database of lightly overconsolidated and sensitive clays to construct the joint probability distribution among the liquidity index and several design parameters. This joint distribution is then used to simulate the correlations between liquidity index and the design parameter of interest. The main results are a set of equations whose inputs are the observed liquidity index and outputs are the updated mean values and coefficients of variation (c.o.v.) of the design parameters of interest, which are necessary for reliability-based design. These equations are further validated by another independent database of lightly overconsolidated and sensitive clays as well as by empirical equations proposed in literature.