2016 年 16 巻 11 号 p. 11_1-11_10
Empirical equations of liquefaction strength curve, which is applicable in wide range of number of cycles causing liquefaction and variety of sandy soil, are proposed for the effective stress analysis. Past similar researches have several disadvantages from the practical point of view; soil classification is not considered and applicable range is limited to small number of cycles or uncertain. In our research, many test results on undisturbed samples which include variety of soil classification and with number of cycles causing liquefaction larger than 100 are collected. About 200 test results are classified based on the geological age and the fines content. Considering the engineering practice, equations predicting RL5 and RL100 from RL20 is proposed by classifying the geological age (Bs+As and Ds). Finally, a smooth equation is proposed for liquefaction strength curve which covers number of cycles causing liquefaction between 5 and 100.