ABSTRACT
It is well known in geotechnical engineering that the suction due to the existence of meniscus water between the soil particles increases the shear strength for unsaturated soils. The magnitude of the suction according to the meniscus water depends on a kind of soils. On the other hand, in order to understand the surface property of the soil material for the formation of the meniscus water, some researches in connection with the interaction between the surface of the particle and fluid have been progressed. Rodriguez and Newaz (1997) insisted that the high free energy on hydrophilic material surface causes the soil particle property drawing water. On the contrary, a surface of a hydrophobic soil particle excludes water and acts as a diffusion barrier for water (Goebel et al., 2007). It has been reported that such differences in surface properties of soil particles result in the clear distinctions even in macro scale (Nguyen et al., 1999; Frattolillo et al., 2005). Differences in surface property determine the water distribution on the surface. Water layer formed on the hydrophilic soil particle is 10 times thicker than the water layer of the hydrophobic soil particle (Derjaguin and Churaev, 1986). Therefore, the surface wettability according to a kind of soils would dominate the formation of
This paper presents the empirical verification on which the existence of meniscus water affects the shear behavior with geomechanical behaviors of both hydrophilic and hydrophobic soils using the direct shear test. In addition, the obtained shear strengths for just hydrophilic sands are discussed by means of the application of the suction stress.
