超大超长群桩基础沉降有限元分析

Fem Analysis of Settlement of Super-ong Group Piles Foundation

超大超长群桩在大跨桥梁和高层建筑中得到广泛的应用。本文以某长江大桥超大超长群桩基础为例,用三维有限元法分析了群桩基础的沉降特性。地基采用理想弹塑性模型,桩身混凝土用线弹性模型模拟,桩-土界面设置了有厚度的薄单元。假定不同大小的地基土弹性模量,分析桩顶沉降规律,研究桩顶沉降、桩身及桩底土层压缩量之间关系。同时,分析了平均桩顶沉降、平均桩顶轴力以及土体弹性模量三者之间的关系。

Super-long and large group piles foundation has been widely used in large bridges and high buildings. As an example of a super-long group piles foundation of a Changjiang River Bridge, the behavior of settlement of the super-long group piles foundation are studied by using three dimensional Finite Element Method （FEM）. Ideal Elasticity Plasticity model is used to simulate the constitutive relation of soils, and linear elastic model is used for concrete of piles. Suppose the different sizes of elastic modulus, the settlement of pile top are analyzed, then the relationship among the settlement, the compression of pile body and compression subsoil underneath piles is studied. Meanwhile, the relationship among the average top settlement, the average load and elastic modulus is also analyzed.