ABSTRACT
Soil stiffness has an important role when analyzing ground deformation in geotechnical engineering practices. It exhibits strong non-linearity, and its strain-dependency is an important parameter to predict ground movement at small strain level. Through investigations of the effects of matric suction on elastic shear modulus, the people can estimate the elastic shear modulus for unsaturated soil with using the appropriate confining stress parameter which takes the effect of matric suction into account. In this chapter, the authors examined the case that the matric suction applies as a part of the confining stress for small-strain behavior. In fine sand, the elastic shear modulus has little changes for increase of the matric suction in comparison with silty soil and decomposed soil. Consequently, when the matric suction increases, the elastic shear modulus increases with the increase of intergranular adhesive force. A silty soil, decomposed soil and fine sand were used with different specimen preparation method.
