Cyclic Strength Evaluation Criteria for Sand-Like, Clay-Like, and Intermediate Soils

This paper reviews recommendations regarding criteria and engineering procedures for evaluating undrained cyclic strengths of sand-like, clay-like, and intermediate soils. The need to distinguish between cyclic strength evaluation criteria and liquefaction susceptibility criteria is illustrated by reviewing two common procedures—one where these two criteria are coincident and one where they are not. Furthermore, a review of alternative liquefaction susceptibility criteria illustrates that their differences can reflect differences in terminology/definitions or intended purpose/application. A logic tree approach is used to illustrate that cyclic strength evaluation criteria, whether explicitly stated or implied, are an essential step in engineering evaluations of potential ground failure or deformations, whereas liquefaction susceptibility criteria that do not coincide with recommended cyclic strength evaluation procedures are not. Cyclic strength evaluation criteria and engineering procedures for evaluating undrained cyclic strengths of sand-like, clay-like, and intermediate soils are described and illustrated through example applications.