筏土接触对基础承载性状影响的数值分析研究

Numerical Analysis of Effects of Raft Soil Contact on Bearing Behavior of Foundation

基于有限元分析方法,建立无桩筏板基础和桩筏基础三维数值模型,通过改变筏板与土体间的界面接触条件,研究摩擦特性对基础竖向承载性状的影响,并对基础荷载与沉降关系、桩土荷载分担比、土体位移场变化规律和桩身结构内力等与土体性质、基础形式、布桩方式等的关系进行讨论。分析结果表明:筏板-土体接触界面摩擦特性对基础竖向承载特性影响不大,基础竖向刚度、桩土荷载分担变化规律与地基弹性模量关系密切,桩身弯矩分布同时受土体类型和桩间距的影响。此外,不同地基中桩土荷载分担比例趋于相同值,以及桩身弯矩变化规律产生差异的原因值得进一步研究。

Based on finite element method,three-dimensional numerical models of unpiled rafts and piled rafts are established. The effects of friction characteristics on vertical bearing behavior of foundations are investigated through changing raft-soil interface properties. Load-settlement relations,pile raft load sharing ratios,laws of soil displacement fields and internal forces of piles are discussed combined with soil properties,foundation types and layout of piles. The results show that the friction between raft and soil has little effects on vertical bearing characteristics of foundation. Vertical stiffness of foundations and pile soil load sharing ratios have close relation to soil stiffness,and the bending moment distribution of piles is affected by soil types and pile spacing. In addition,the reasons why pile soil load sharing ratios in different soils gradually tend to be the same and the differences of bending moment of piles in different soils are worthy of further study.