압축파와 전단파를 이용한 불포화토의 간극비 산정

Abstract

Soils are commonly unsaturated in the near surface. The stiffness of soils is affected by the amount of air and water. The objective of this study is to evaluate the porosity of the unsaturated soils by using the elastic waves including compressional and shear waves. The elastic waves are measured at different degrees of saturation by controlling the matric suction. Thus, the unsaturated soils are characterized at different levels of the matric suction. Shear and compressional waves are measured by using the bender elements and the piezo disk elements, respectively. Both transducers are installed on the walls of the rectangular cell. The unsaturated soils are prepared by using uniform size sands and silts. Test results show that both compressional and shear wave velocities change according to the matric suction. The elastic modulus, the shear modulus, and the Poisson`s ratio are estimated based on the measured elastic wave velocities. In addition, the void ratio of the unsaturated soils estimated using elastic wave velocities matches well with the volume based void ratio. This study demonstrates that the elastic waves can be effectively used for the characterization of unsaturated soils.