冲刷对受荷群桩承载特性的影响分析

Analysis of the Impact of Erosion on the Bearing Characteristics of PileGroup Foundations Under Load

【目的】冲刷深度对桩体承载特性具有重要影响,冲刷会引起桩体的变形增大,使土壤中的有效侧阻力和端阻力减小,进而使桩的承载能力减退,对桩体的动力特性也有影响,因此有必要对冲刷后桩体承载特性进行研究。【方法】通过有限元数值模拟,分别对不同冲刷深度下桩体回弹量、极限承载力、各桩轴力与侧摩阻力进行研究。【结果】冲刷会导致土体卸荷回弹,随着冲刷深度的增加,桩顶回弹量增大,土体卸荷回弹更加显著。在荷载达到12000 kN至极限荷载的过程中,由于桩顶承受的荷载较大,荷载对桩体的向下位移的影响大于土体冲刷卸荷回弹对桩体向上位移的影响,从而导致整体上桩体位移随冲刷深度的增加而增大。【结论】研究成果可为冲刷对群桩承载力影响分析提供理论依据。

[Purposes]Scouring depth has a significant impact on the bearing characteristics of pile foun-dations.Scouring can cause increased deformation of the piles,resulting in a decrease in effective lateral and end resistance in the soil.This,in turn,reduces the bearing capacity of the piles and also affects their dynamic characteristics.Therefore,it is necessary to study the bearing characteristics of pile foun-dations after scouring.[Methods]Byfinite element numerical simulation,the rebound displacement of the pile,ultimate bearing capacity,axial forces,and lateral friction resistance of the pile under different scour depths were studied.[Findings]The results indicate that scouring can cause unloading rebound of the soil,and as the scour depth increases,the rebound displacement at the pile head increases,and the unloading rebound of the soil becomes more significant.During the process from the load reaching 12000 kN to the ultimate load,due to the large load borne by the pile head,the downward displacement of the load on the pile is more influential than the upward displacement caused by scour-induced unload-ing rebound of the soil,resulting in an overall increase in the displacement of the pile with increasing scour depth.[Conclusions]The research findings provide a theoretical basis for the analysis of scour's impact on the bearing capacity of pile foundations.