Abstract
In this study, the authors have taken a case study of landslide caused by partial liquefaction of sheer zone. The dealt landslide is located at Hakaba in Hamada city in Shimane Prefecture which occurred on the occasion of the Shimane disaster in 1983.
The critical condition of liquefaction of sandy materials without earthquake was studied by the undrained load cotrolled triaxial compression test in use of the Toyoura standard sand and a torrent doposit susceptible of debris flows. As a result, the void ratio and the degree of saturation were found to be the most effective factors concerning the critical condition of liquefaction.
The undrained load controlled triaxial compression test of the soil sampled at the Nakaba landslide has revealed that the grain size distribution characteristic is also an important factor on liquefaction, namely the lack of relatively finer grains leads to the liquefaction on the occasion of rapid loading.
Authors have concluded that, in case of the Nakaba landslide, a small upper landslide gave rapid loading to the lower slope where finer grains above the bed rock had been eroded by ground water, and it resulted in prtial liquefaction of this eroded and saturated zene. It caused the main disastrous landslide destroying seven houses and killing fifteen persons.
