The design of bearing capacity is essential for enhancing the resistance of bridge foundations to scour-related damage. However, most studies estimate this capacity solely based on visible scour depth, neglecting the complexities introduced by sediment yielding and backfilling layers above the actual bed surface, which are difficult but crucial to detect for accurate assessment. This paper addresses this gap by proposing a comprehensive method for simulating local scour around bridge piers and precisely identifying backfill soil following scour events. Specifically, this paper introduces a meshless method that integrates a multiphase sediment model, adaptive boundary algorithms, and a novel approach for recognizing backfill sediments, all implemented using the open-source smoothed particle hydrodynamics (SPH) solver DualSPHysics. In this method, the bed load and suspended load are used to differentiate the sediment state during scour based on the critical velocity criteria. Further, the identification of backfilled sediments is achieved by marking the settling suspended loads. The accuracy of method is validated through comparisons with two experimental studies on scour effects. Upon validation, the results of backfill sediment identification are presented, showing that the backfilled region around the monopile forms a semiannular pattern at a short distance from the pier, with an approximate coverage of 66% and a thickness equivalent to roughly 13% deepest depth of scour hole.
Zhang et al. (Fri,) studied this question.