Research on the collapse prediction of unsaturated Shirasu slopes in earthquake

白洲有大的浮石。未受扰动的白苏似乎是软岩这样的脆性材料，但受扰动的白苏被称为颗粒土。对含有可压碎颗粒的火山土白须进行了一系列不排水单调三轴试验。结果表明，白须岩的不排水循环和单调剪切特性与围压和密度有很大的关系。对受干扰的样本进行了检测。(1)白砂的单调和循环不排水剪切行为对围压有很强的依赖性，丰浦砂则没有。(2)在偏应力比和轴向应变中，松散白须的偏应力比随初始有效围压的增大而增大。而致密白砂的偏应力比随初始围压的增大而减小。(3)松质白砂的剪切特性随初始有效围压的增大而增强。另一方面，对于致密的Shirasu，随着初始围压的增加，表现出越来越多的收缩行为，这与通常发现的桑迪一样。

Shirasu has large pumice stone. Undisturbed Shirasu is seemed such brittle material as soft rock, but disturbed Shirasu is known as a granula soils. Aseries of undrained monotonic triaxial tests has been performed on a volcanic soil Shirasu which has crushable particles. As a result, the undrained cyclic and monotonic shear behavior of Shirasu is found to greatly dependent on the confining pressure and its density. Testing was performed on disturbed spcimens.(1) The monotonic and cyclic undrained shear behavior of Shirasu shows a strong dependence on confining pressure, Toyoura sand does not.(2) In the deviator stress ratio and axial strain for loose Shirasu the deviator stress ratio increased with increasing initial effective confining pressur. The deviator stress ratio for dense Shirasu had the opposite trend of decreasing with increasing initial confining pressure.(3) The shear behavior of loose Shirasu showed increasing dilative characteristics with increasing initial effective confining pressur. That for dense Shirasu, on the other hand, showed increasingly contractile behavior with increasing initial confining pressur as is generally found for sandy.