Modeling of Partially Cemented Soils in the Las Vegas Valley

Cemented soils deposits located in Las Vegas valley have long been a challenge for engineers. These deposits can distribute considerable loads over a large area. They are, however, difficult to model or to predict their behavior. For engineering purposes, these cemented soils, also commonly referred to as Caliche, are difficult to characterize: their thickness, lateral extent and strength. This erratic and heterogeneous nature can result in inconsistent design and performance of foundations. Fifty-three cored specimens from block samples of partially cemented soils (aka Caliche), collected from the Las Vegas valley, were tested for their unconfined compressive strength (UCS). Laboratory shear and pressure wave velocities were measured for all samples and relationships between lab shear wave velocities, material unit weight and unconfined compressive strength were generated. This article discusses a material model for the partially cemented soils using results obtained from these UCS tests. The model, which uses parameters from shear wave velocity correlations, generates the stress-strain relationship of cemented soils and distinguishes three cementation levels.