Abstract
Empirical equation of liquefaction strength curve, which is applicable in wide range of number of cycles causing liquefaction, is proposed for 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, test results of undisturbed samples with variety of soil classification and with number of cycles causing liquefaction larger than 100 are collected. About 200 test results are classified from several points of view. It is found that both geological age and fine fraction content are important factors. Considering the use of practical engineering, equations predicting RL5 and RL100 from RL20 is proposed based on geological age (Bs+As or Ds). Finally, a smooth equation is proposed for liquefaction strength curve which covers number of cycles causing liquefaction between 5 and 100.
