抄録
The shear property at the residual state is a very important strength in engineering, as usually used for landslide stability analysis. We examined the microscopic structure of the shear surface and spectroscopic property of adsorbed water. As a result of AFM measurement of shear surface it became clear that shear surface was not a perfect flat, and also by CLSM observation, we found that the contact part of a glass board and a shear surface of clay was only partial contact. It indicates that the area actually touched was smaller than the apparent contact area. The "actual contact area" increased as the normal stress increased. While with FTIR measurement, adsorbed water on shear surface of cohesive soil decreased as the increase in normal stress. In conclusion, the coefficient of residual state shear resistance (tanφ_r) of clay can be thought to be the coefficient originated in the increase in the actual contact area caused by the increase in the normal stress.
