Ring shear tests on clays of fracture zone landslides and clay mineralogical aspects

Abstract

Various investigations on tectonically-induced landslides in Shikoku Region of West Japan have been carried out, most of which conclude at tectonic activities through the major tectonic faults and enhanced rock mineral decomposition as being mainly responsible for the landslide occurrence. This paper looks into strength parameters of the landslide clays, as measured in ring shear apparatus, from clay mineralogical point of view. As a result of strength tests and X-ray diffraction analysis, it is found that the drop from peak to residual friction angles for the tested samples reaches as high as 20°, and the residual strength of the landslide clays was found to decrease with higher amount of expansive clay minerals, which was estimated as being relative to chlorite mineral. © 2007 Springer-Verlag Berlin Heidelberg.