2018 Volume 13 Issue 3 Pages 171-181
This paper presents the physical properties of volcanic soil sampled at Takanodai area, Minamiaso village, Kumamoto Prefecture in JAPAN, where long-runout slope failures took place by the main shock from the 2016 Kumamoto earthquake. A series of box shear tests under various conditions such as constant stress, constant volume and cyclic shear has been carried out for undisturbed samples of pumice fall deposits to evaluate strength properties and seismic behaviors. Based on the results of Newmark displacement method, the seismic displacement of pumice fall deposits layer shows rapid increase because of the strength reduction induced by the crushability of pumice fall deposit while pumice fall deposit layer has enough stability under normal condition, which is considered to be one of the factors to cause long-runout slope failures at the above site.
