抄録
Laboratory tests on friction between cohesive soils and mild steel were carried out using a direct simple shear type of test apparatus. The cohesive soils were normally consolidated Kawasaki clay and four kinds of normally consolidated sand-clay mixtures. All tests were carried out under consolidated drained shear condition. Frictional behaviour observed was as follows : (1) There was little difference in the maximum coefficient of friction between the tests with different mixture ratios of sand. After sliding had occurred between steel and a soil with a high clay fraction, however, the residual coefficient of friction at the applied displacement of 15 mm was much smaller than the maximum coefficient of friction. (2) The critical value of steel roughness is the boundary value whether interface sliding occurs or not. It was larger for a soil with a higher sand fraction. (3) For the friction of sand-clay mixtures with steel roughness of 20 and 30 μm Rmax over a gauge length of 0.2 mm, interface sliding and shear deformation of the soil specimen proceeded simultaneously. (4) Frictional behaviour was classified into three failure modes, namely full sliding at the interface, shear failure within the soil, and the mixed behaviour where interface sliding and shear deformation of the soil specimen proceed simultaneously.
