基于FLAC^(3D)的超长大直径钢管桩竖向承载特性模拟

Simulation of vertical bearing features for large-diameter and super-long steel pipe pile based on FLAC^(3D)

近年来,超长大直径钢管桩在工程中的应用已越来越多,但对其承载特性的研究却很少,设计中仍然参考普通桩的计算理论。本文采用三维连续介质快速拉格朗日法(FLAC3D)对实际工程中一超长大直径开口钢管桩试桩的竖向承载特性及沉降特性进行了数值模拟分析,并将模拟结果与静载荷竖向承载特性试验实测结果进行了对比,两者相互补充和相互验证,取得了比较一致的结果,表明了本文所编制的有限差分程序用以初步模拟分析超长大直径钢管桩承载特性的可行性。研究结果表明:超长大直径钢管桩是典型的端承摩擦型桩;桩侧摩阻力随深度的变化很复杂,其变化与土性密切相关;桩身轴力向下传递的速度与桩侧摩阻力在不同土层中的发挥程度息息相关。这些结论对实际工程中超长大直径钢管桩基础的设计具有参考意义。

More and more large-diameter and super-long steel pipe piles are applied to engineering in recent years.But so far,few people have focused on studing their bearing characteristics.Computational theory of ordinary piles is referenced in the foundation design.Vertical bearing and settlement features are simulated for large-diameter and super-long steel pipe piles based on the fast Lagrangian analysis of continua in three dimensions（FLAC3D）.Then comparison between simulation results and the results of vertical static load bearing capacity test is conducted and they are complemented and verified each other.The consistent results demonstrate that the method of using the finite difference procedure in this paper to preliminarily simulate the vertical load-bearing characteristics and settlement characteristics of large-diameter and super-long steel pipe pile is feasible.The study shows that the large-diameter and super-long steel pipe pile is a typical end-bearing friction pile.The pile lateral friction resistance changes intricately with depth,which is closely related to the soil characteristics.And the transferring speed of pile axial force depends on the action of pile lateral friction resistance in the different soil.These conclusions are of significance for the reasonable large-diameter and super-long steel pipe pile foundation designed in engineering applications.