Use of shear wave velocity to evaluate in-situ state of silty sands

Abstract

In design of large-scale earth structures such as hydraulic-placed fills for artificial islands or tailings dams, a major concern is the susceptibility of the silty sands involved to flow failure or liquefaction. Compared with uniform clean sands that have been extensively studied in the laboratory, the large-strain behavior and liquefaction potential of silty sands is not yet well understood partly due to the complex role of the fine particles. A difficult problem in the liquefaction evaluation in practice is to evaluate the insitu state of the soil; this is because for sandy soils it is extremely difficult and costly to obtain high-quality undisturbed samples. This paper presents a framework for evaluation of the in-situ state of silty sands by using shear wave velocity measurements. The framework is built upon a comprehensive experimental program involving shear wave measurements for both clean sand and sandfines mixtures in conjunction with interpretation and analysis in the theory of critical state soil mechanics. Since shear wave velocity can now be reliably measured both in the laboratory and in the field and since the initial state controls different aspects of the stressstrain behavior of sandy soils, the proposed framework is highly promising in a variety of geotechnical applications