Several methods to evaluate cyclic undrained strengths of sandy soils from standard penetration resistances (N-values) are reviewed and compared. It is shown that some empirical equations which do not take account of the effects of grain size on N-values can be rather conservative for fine or silty sands. When the effects of grain size on N-values are adequately taken into account, strengths estimated from N-values are very close to the measured strengths of undisturbed samples. A simplified procedures for evaluating liquefaction potential of an element is proposed. An index showing integrated liquefaction potential of a deposit is also proposed and examined by a liquefaction case study.
