Large deformation analysis of ALE method for seismic liquefaction of caisson wharf

Abstract:

Based on the soil-water two-phase mixing theory and the operator separation technology, a decoupled Arbitrary Lagrangian Eulerian method (ALE method) was developed, aiming to overcome the analysis interruption caused by mesh distortion in large deformation analysis of traditional updated Lagrangian (UL )method. The ALE method was applied to the seismic liquefaction analysis of caisson wharf on loose sand foundation. Results show that the ALE method could complete the seismic response analysis of caisson wharf under strong earthquake when the UL method failed, and provide numerical solutions with higher accuracy while maintaining the mesh quality. In addition, the ALE method was applied to the assessment of liquefaction mitigation measures of caisson wharf, providing a method for the optimal design of caisson wharf on loose sand foundation. Results show that the displacement response of caisson structure and the uplift of the front of the caisson toe could be significantly reduced by soil densification in replacement region. Soil densification in backfill region could reduce the displacement response of caisson structure under the condition of soil non-densification in replacement region, but it had little effect on the displacement of caisson structure under soil densification in replacement region. Both the replacement region and the backfill region had critical densification ranges, and there was no obvious change in the displacement response of the caisson structure while exceeding the critical densification ranges. The combination of gravel piles with densification in replacement region and backfill region could further decrease the displacement response of the caisson structure and increase the anti-liquefaction potential of the caisson structure.