A Strain‑Consistent Vs‑Based Framework for Liquefaction Assessment: From Small‑Strain Shear‑Wave Velocity to Large‑Strain Cyclic Response

Traditional liquefaction assessment methods based on small-strain shear-wave velocity (Vs), such as those proposed by Andrus & Stokoe (1997, 2000), relate to the cyclic resistance ratio (CRR) through empirical boundary curves. Although widely adopted, these approaches implicitly assume that small-strain stiffness can be used as a direct proxy for large-strain cyclic behavior, thereby neglecting the nonlinear degradation of shear modulus, the evolution of material damping, and the progressive generation of excess pore pressure. This paper introduces a new strain‑consistent Vs‑based framework that transforms into a complete cyclic response model through three physically grounded steps: i) normalization of and derivation of a shear‑wave‑velocity‑based state index ; ii) generation of modulus reduction and damping curves and consistent with the inferred state; iii) prediction of excess pore pressure build‑up through a parametric function driven by the equivalent cyclic shear strain . The method requires only profiles and basic stress information, without the need for CPT or SPT data, and incorporates a probabilistic treatment of thin, low‑stiffness layers that may be smeared by surface‑wave methods. Calibration procedures and the necessary laboratory datasets (RC, TS, and cyclic undrained tests) are presented. Overall, the proposed framework overcomes the conceptual limitations of existing Vs‑based CRR correlations by establishing a physically consistent pathway from small‑strain stiffness to large‑strain cyclic deformation and liquefaction triggering, enabling a more transparent and mechanistically sound assessment of liquefaction potential.