長野市地附山地すべりの土質特性と運動

Abstract

A big landslide occurred at Jizukiyama, Nagano Pref., 1985. This landslide was remarkedthat the sliding mass overcame a gentle slope of 8 and went 100-200m during only someten minutes. The long distance of motion is seemed to be supported by the pore-pressureoccurance and while the sliding mass loaded on fully or nearly saturated ground, and itresulted in the decrease of the frictional resistance of soil. So, soil tests were carried out onthe Jizukiyama soil, and the pore-pressure coefficients and other constants were measured.Further, these coefficients were applied to Sassa's "The Improved Sled Model", and the apparentfriction angle of Jizukiyama Landslide was calculated. The obtained apparent friction angleis reasonable to explain its long travel distance of the Jizukiyama landslide.