Application of shear wave velocity for characterizing clays from coastal regions

Demand for infrastructure development in coastal regions where the subsurface is often composed of soft clays, results from the desire for rapid industrialization. The frequently encountered coastal soil conditions often call for suitable ground improvement and modification techniques to prepare soft deposits for foundation construction. For appropriate site improvement, several engineering soil properties are desired which require expensive and time consuming field and laboratory testing. Under such circumstances, empirical correlations based on routinely determined soil properties would be very useful and economical in planning of the project. With this as a goal, undisturbed samples from three on-shore and off-shore sites of the coastal regions in India, where major infrastructure projects are being executed, were collected. These samples were tested for physical, chemical, mineralogical and geotechnical characteristics. In addition, shear wave velocity of specimens of these soils was determined by using bender elements. Based on this data, empirical correlations between void ratio, compression index and undrained shear strength with shear wave velocity of clays were developed. Because shear wave velocity can be easily determined in the laboratory, these correlations are found to be valuable for preliminary planning of the project. The utility of these correlations for preliminary characterization of the soft soil has also been demonstrated.