Earthquake-induced flow-type slope failures in volcanic sandy soils and tentative evaluation of the fluidization properties of soils

Japan has many experiences of mudflow-type failures of volcanic sandy soil slopes during earthquakes. Firstly in this paper, several major cases of the flow-type failures are outlined. In general, undisturbed pyroclastic deposits have high strength against to fluidization because of its cementation effect. However, once the deposits are disturbed to use as an earth fill materials, the shear strength of disturbed soils cannot be expected. Rather, the disturbed pyroclastic soils are weaker than ordinary sandy soils. Therefore, it is necessary to evaluate the fluidization property of disturbed pyroclastic sandy soils for mitigating mudflow disaster. In this study, we introduce a drum type testing machine to evaluate the fluidization property. Two kinds of volcanic sandy soils are used as a specimen sampled from volcanic area in Japan. In addition to this, the wireless multi sensor which can be installed in the movable soils is introduced.