柔性基础下刚性桩复合地基的工作性状

采用数值方法,考虑复合地基、垫层和基础之间的共同作用,对柔性基础下刚性桩复合地基桩侧摩阻力、桩身轴向应力、桩端刺入变形等工作性状进行了研究;讨论了基础弹性模量、基础高度、基础宽度、桩体弹性模量、置换率、土体弹性模量等因素对复合地基工作性状的影响;最后通过归一化分析提出了可反映基础相对刚度的量纲一的参数K,并讨论了不同基础相对刚度下桩端上刺变形的变化趋势。结果表明:基础弹性模量并不是区分柔性基础与刚性基础的惟一指标,采用"基础相对刚度"的概念比仅考虑基础自身刚度的概念更具有合理性。

Working Behavior of Composite Ground Improved by Rigid Piles Under Flexible Foundation

Considering the interaction among composite ground,bedding course and foundation,the working behaviors of composite ground under the flexible foundation,such as the friction resistance,axial stress and the penetrating displacement of pile were studied by FEM and the influences of some factors on the working behaviors of composite ground were discussed,including the elastic modulus,height,width of foundation,the replacement ratio of pile,and the elastic modulus of pile and soil.At last,dimensionless parameter K which reflected the relative rigidity of foundation was defined,and variation tendencies of the penetrating displacement of pile top with different K values were discussed.It shows that the elastic modulus of foundation is not the only parameter which distinguishes flexible foundation from rigidity foundation.The concept of relative rigidity of foundation contrasting with concept of foundation self-rigidity is reasonable.