基于Burgers模型的软土桩基长期沉降计算方法

A Computational Method of Long-term Settlement for Pile Groups in Layered Soft Soil Based on Burgers Model

软土桩基础的沉降可能会持续几十年,其长期沉降计算一直困扰着广大岩土工程技术人员。笔者基于Burgers模型,建立了桩身和桩端的黏-弹性荷载传递模型,并以此为基础,考虑群桩效应,建立了桩-土-承台变形耦合的软土桩基长期沉降计算模型,并编制了计算程序CLPS。该计算方法能够计算多层软土桩基的长期沉降,而且适用于刚性承台和柔性承台桩基的长期沉降。使用该方法对2处软土桩基进行了长期沉降计算。结果表明该方法计算结果与实测值较为接近,两者最大相差不超过18.8%,最小仅为4.6%;与三维有限元计算结果非常接近,两者最大相差不超过6.7%,且该方法计算效率远高于有限元分析方法。

Engineering practice shows that the settlement of pile groups in soft soils will be lasting for several decades,due to the creep or viscoelastic behavior of soft soils around the pile,but the calculation method for the long-term settlement of pile groups in soft soils was always a puzzle for geotechnical engineers. For that reason,an approach used the load transfer（t-z） model to simulate the pile-soil interaction by a series of Burgers model distributed along the pile shaft and the pile base,and a nonlinear approach to calculate the long-term settlement of pile groups in layered soft clay soil was proposed in this work. A program named CLSP（Calculating Long-term Settlement of Pile foundation） has been developed in Matlab to analyze the long-term settlement of two pile groups in layered soft soils. Comparisons of the calculations and the measurements show that the maximal error of the calculations and the measurements is no more than 18.8%,and the minimal is only 4.6%. Comparisons of the CLSP and the ABAQUS present that the CLSP calculation result is very closed to the ABAQUS,and the maximal error of them is no more than 6.7%,what＇s more,the computational efficiency of the CLSP is faster than that of ABAQUS.