散体材料桩复合地基沉降计算的分层总和法探讨

Study on layer-wise summation method of settlement computation for composite foundation with friable material piles

在深入研究散体材料桩复合地基沉降变形机理基础上,考虑到散体材料桩复合地基由于受载或变形引起桩土孔隙率变化导致桩土变形力学参数变化的特点,建立出散体材料桩复合地基桩土变形模量和泊松比与变形的关系模型。然后,基于散体材料桩复合地基沉降计算的非线性特征,引进传统分层总和法和分级加载的思想,提出了刚性基础下散体材料桩复合地基沉降计算新方法。该方法避免了复合地基桩土压缩曲线和经验修正系数的使用,也考虑了散体材料桩复合地基桩土相互作用的影响,完善了散体材料桩复合地基沉降计算的理论与方法。最后,通过工程实例计算与分析,并与其它方法进行比较,表明了本文方法的合理性与可行性。

Firstly, based on studying settlement and deformation mechanism of composite foundation with friable material piles, a model describing the relation of deformation modulus and Poisson＇s ratio to deformation of composite foundation is developed by considering the features that mechanical parameters of piles and soil change with their porous ratio because of load or deformation. Afterwards, an idea about traditional layer-wise summation method and step loading are introduced, and a new layer-wise summation method of settlement computation for composite foundation with friable material piles under rigid foundation is proposed by considering nonlinear characteristic of settlement. It can avoid the use of compressive curves and experiential correction coefficient, reflect the impact of the soil-pile interaction of composite foundation with friable material piles, and the theory and method of settlement computation for composite foundation with friable material piles are improved. Finally, the computation and analysis of practical engineering as well as comparison with other methods shows that the new layer-wise summation method proposed in this paper is both feasible and reasonable.