Laboratory measurement of small strain shear modulus of volcanic soil

Abstract

Volcanic soils can be found in many places around the world. In comparison to conventional soils, their mechanical behavior is less extensively studied in the laboratory. In this study, a series of laboratory tests has been carried out to investigate the small-strain shear modulus (G0) of a volcanic soil sampled from northeastern Japan, using the resonant column and bender element techniques. Specimens were prepared at different packing densities and confining stress levels. The G0 values of the original volcanic soil samples and the sieved soil samples without the fine particles (diameter < 63μm) were measured to examine the influence of the fines. Selected test results are presented and discussed in this paper and are compared with that of two clean quartz sands that are commonly used in the laboratory. It is found that the G0 value of the original volcanic soil is markedly lower than that of the clean quartz sands under otherwise similar conditions but the G0 value increases substantially if the fine particles are removed from the original soil samples. The study indicates that fine particles play an important role in the mechanical behavior of the volcanic soil.