抄録
Laboratory tests on friction between normally consolidated Kawasaki clay and mild steel were carried out by using two types of direct shear test apparatuses, namely, simple shear type and shear box type. The excess pore water pressure at the interface was measured. Frictional behaviour obtained was as follows : (1) There existed a critical steel roughness of approximately 10 μm Rmax (L=0.2 mm). When the steel surface was smoother than the critical roughness, interface sliding occurred, followed by the reduction in frictional resistance. When the steel roughness exceeded the critical value, however, shear failure occurred within clay specimen, so that the maximum resistance of friction agreed with shear strength of clay. (2) The angle of interface friction in terms of effective stress did not depend on drainage condition and consolidation pressure of clay. (3) The loading speed was influential in the maximum resistance of friction, while less influential for smoother steel surface, and of little influence on the residual resistance of friction at the applied displacement of 10 mm. (4) For the tests of shear box type, shear strength of clay did not agree with the upper limit of the maximum resistance of friction, which was obtained when shear failure occurred within clay specimen. This was due to the difference of shear deformation of clay specimen in the shear box.
