Abstract
Ring shear and reversal box shear tests are conventionally used for measuring the residual strength of soils. In this paper the normal stress, the overconsolidation ratio, the shear displacement rate and the change in the normal stress during the shear process are considered among many factors affecting the test results. It was shown that the residual strength obtained in a low range of the normal stress should be interpreted based on the properties of the direct shear test apparatus. The residual strength is almost constant to the change in the overconsolidation ratio, but it changes in relation to the shear displacement rate, depending on the type of soils. The stress paths of the soil specimen which have once reached the residual strength move along the residual strength line accompanying the change of the normal stress.
