Seismic Liquefaction Evaluation Method for Saturated Sandy Soils with Nonplastic Fines Content Based on Strain Energy

Coral sandy soils are widely distributed and commonly utilized as materials for engineering foundations or construction, exhibiting a high potential for seismic hazards. In this study, complex cyclic loading tests were conducted on coral sand with varying fines contents and relative densities. The strain energy–based failure criterion is formulated by analyzing the variation in dissipated energy of specimens under complex cyclic loading conditions. This approach effectively mitigates inconsistencies between excess pore-water pressure (EPWP) and strain development under complex cyclic stress paths. The proposed criterion reveals that the cumulative dissipation energy of failure (Wf) remains unaffected by cyclic loading conditions but is notably influenced by the initial physical state of the material. A negative power function relationship exists between Wf and the equivalent intergranular void ratio (e*). Additionally, the cyclic resistance ratio corresponding to 15 failure cycles exhibits a negative power function relationship with e*. By defining the energy ratio, this study establishes an arc-tangent function model for the relationship between the energy ratio and EPWP ratio. Furthermore, a power law function model describing the increase in deviatoric strain amplitude with cumulative dissipated energy is proposed. The validation of the tests on siliceous sandy soils in the literature confirms the wide range of applicability of the model proposed in this paper.