Predictive model for shear wave velocity of gravelly soil and its application to liquefaction triggering assessment

Several studies have established empirical correlations between shear wave velocity (V_s) and standard penetration test blow count (SPT-N) for engineering use. However, these empirical correlations cannot be applied to gravel-rich soils since the measured SPT-N is often inflated in gravel. Therefore, an empirical correlation of V_s for gravel is developed in this study using the Engineering Geological Database for the Taiwan Strong Motion Instrumentation Program. The V_s predictive model considers gravel content (GC) and coefficient of uniformity (Cu) in addition to effective vertical stress, void ratio, fines content, plasticity index, and overconsolidation ratio, which have been considered previously. The proposed model indicates that V_s increases with GC and Cu. Moreover, the V_s adjusted for GC can be used with existing V_s -based liquefaction triggering relationships to rationally define the boundary between liquefaction and non-liquefaction case histories with different GCs.