静钻根植竹节桩桩端承载性能数值模拟研究

静钻根植竹节桩是一种新型组合桩基，桩端处存在的水泥土扩大头使其桩端承载性能优于传统桩基。通过模型试验以及ABAQUS三维建模计算对静钻根植竹节桩的桩端承载性能进行研究时发现，当桩端土体为砂土或黏性土时，预制竹节桩桩端处于水泥土扩大头中间位置附近时桩端极限承载力最大；当桩端持力层为岩石层时，竹节桩桩端与岩石层之间水泥土层厚度越小，桩端承载性能越好。由于现阶段静钻根植竹节桩主要用于东南沿海软土地区，实际工程中竹节桩桩端处于水泥土扩大头中间位置附近时桩端承载性能最好；桩端水泥土的内摩擦角、黏聚力以及弹性模量对静钻根植竹节桩桩端承载性能影响不大；增加水泥土扩大头的直径能够提高静钻根植竹节桩的桩端承载力。

Numerical simulation of tip bearing capacity of static drill rooted nodular pile

The static drill rooted nodular pile is a new type of composite pile foundation; its tip bearing capacity is promoted as the existence of the enlarged cemented soil base. A group of model tests and ABAQUS simulation are used to investigate the tip bearing capacity of this pile foundation. The results of ABAQUS simulation show that the ultimate tip bearing capacity reaches the maximum value when the nodular pile tip is about at the middle of the enlarged cemented soil base in sandy or clayey soil; while the bearing capacity will be promoted with the thickness of the cemented soil between the nodular pile tip and base soil layer decreasing if the base layer is rock; as a result, the nodular pile tip should be at the middle of the enlarged cemented soil base as the static drill rooted nodular pile is mainly used as frictional pile foundation; the internal friction, cohesion and elastic modulus of the cemented soil have little influence on the tip bearing capacity of the static drill rooted nodular pile; the ultimate bearing capacity of the static drill rooted nodular pile will be promoted with the diameter of the enlarged cemented soil base increasing.