抄録
The investigation of liquefaction-induced ground failures during the Kanto earthquake in Tokyo lowland shows that the sandy deposits containing only a small amount of fines were more prone to liquefy rather than those containing considerable amount of fines. The undrained cyclic strength of undisturbed specimens containing fines is considerably strong in spite of small SPT N-values. The formula estimating liquefaction strength proposed herein is formed not only with SPT N-values, effective overburden pressure and mean diameter, but also with fines contents and confining stress. The grounds which consist of liquefiable sandy deposits within surface layers are generally likely to induce severe ground failures. So a criterion of liquefaction susceptibility with FL values of surface layers is proposed herein in order to estimate liquefaction potential for wide area. According to the comparison between the liquefaction analysis for boring records in actually liquefied sites and unliquefied sites during the earthquake, combination of FL values on sandy surface layers and PL values gives more reasonable estimation.
