钙质石灰岩中桩基轴向承载特性的有限元分析

Finite element analysis of axial bearing capacity behavior of pile foundation in calcareous sediments

为了研究钙质石灰岩中桩基的合理设计理论及开发相关的变形破坏数值分析方法,利用弹塑性有限元方法对以硫球石灰岩作为持力层的桩基现场轴向载荷试验进行了数值分析。有限元分析中钙质石灰岩被假定为理想弹塑性材料。结果表明,如果能在有限元解析中合理地考虑桩侧摩阻力的低减效果,弹塑性有限元计算可以较好地模拟与分析钙质砂土中桩基的轴向承载力特性。最后还对开口钢管桩基的土塞效应的发生机制进行了分析。

In order to develop a rational numerical analysis and design method for predicting the bearing capacity and deformation of the pile foundation on Ryukyu calcareous sediments, a series of nonlinear elastoplastic finite element analyses are conducted to simulate pile vertical loading tests. In the finite element analyses, the calcareous soil is modeled as an elastic perfectly plastic material. The load and displacement relation of pile foundation is analyzed with different strength reduction factors for the interface between the pile and calcareous sediment. The analytical results indicate that the strength reduction factor significantly affects the load and displacement of pile foundation on Ryukyu calcareous sediments; and that the proposed FEM could reasonably simulated the experimental results when an appropriate strength reduction factor is used. In addition, the soil plugging effect for open-ended piles is also examined from the FEM results.