Assessment of Seismic Intensity Measures on Liquefaction Response: A Case Study of Yinchuan Sandy Soil

The proliferation of tunnel and subway networks in urban areas has heightened concerns regarding their vulnerability to seismic-induced liquefaction. This phenomenon, wherein saturated sandy soils lose strength and behave like a liquid under seismic waves, poses a catastrophic threat to the structural integrity and stability of underground constructions. While extensive research has been conducted to evaluate liquefaction triggering, most existing approaches rely on single ground motion intensity measures (e.g., PGA, IA), which often fail to capture the combined effects of amplitude, energy, and duration on liquefaction behavior. In this study, the seismic response of saturated sandy soil from Yinchuan was analyzed using the Dafalias–Manzari constitutive model implemented in the OpenSeesPy platform. The model parameters were carefully calibrated using laboratory triaxial results. A total of ten real earthquake records were applied to evaluate two critical engineering demand parameters (EDPs): surface lateral displacement (SLD) and the maximum thickness of the liquefied layer (MTL). The results show that both SLD and MTL exhibit weak correlations with conventional intensity parameters, suggesting limited predictive value for engineering design. However, by applying Partial Least Squares (PLS) regression to combine multiple intensity measures, the prediction accuracy for SLD was significantly improved, with the correlation coefficient increasing to 0.81. In contrast, MTL remained poorly predicted due to its strong dependence on intrinsic soil characteristics such as permeability and fines content. These findings highlight the importance of integrating both seismic loading features and geotechnical soil properties in performance-based liquefaction hazard evaluation.