碎石桩加强软土地基的数值模拟研究

用碎石桩加强软弱土地基是水利工程中最常用的地基改良技术之一,但桩土界面处的显著水力梯度会促使粘土颗粒迁移到碎石桩孔隙中,导致阻塞,进而对软土的固结速率产生不利影响。同时,碎石桩的承载力大小主要取决于周围软土提供的侧向约束,而在深度较浅处所受围压较小,碎石桩可能发生侧向变形进而凸胀破坏。因此,基于快速拉格朗日有限微分数值模型,深入研究了碎石桩加固软土地基的荷载-沉降和固结特性,且分析了阻塞和侧向变形因素的影响。另外,模型还引入了时间变量,探讨了阻塞效应、荷载传递、横向变形随时间变化的特性,计算结果与实际情况有很好的一致性。

Study on Numerical Simulation of Soft Soil Foundation Reinforced by Gravel Pile

Strengthening weak foundation with gravel piles is one of the most commonly used improvement techniques in hydraulic engineering. However, the significant hydraulic gradient at the pile-soil interface is likely to promote the migration of clay particles into the pores of gravel piles, which leads to blockages and adverse effect on consolidation rate of soil. In addition, the bearing capacity of the gravel piles mainly depends on the lateral restraint provided by the surrounding soft soil, while the confining pressure is smaller at a shallower depth, therefore, the gravel piles may undergo lateral deformation and bulge damage. Consequently, the load-settlement and consolidation characteristics of the soft soil foundation reinforced by gravel piles are deeply studied based on the fast Lagrangian finite differential numerical model, and the factors of blocking and lateral deformation factors are also analyzed. Furthermore, the analysis model also introduces the time variable and discusses the blocking effect, load transfer, and lateral characteristics. The calculation results are in good agreement with the actual situation.