三剪统一强度准则在碎石桩复合地基承载特性分析中的应用

对桩身和桩周土分别采用实心圆柱体模型和柱形孔扩张模型,根据桩土间的应力传递及变形协调条件,利用三剪统一强度准则对碎石桩复合地基的承载特性作了分析。导出了碎石桩复合地基桩土应力比、碎石桩及复合地基极限承载力计算式。实例计算表明:碎石桩复合地基的桩土应力比随置换率的增大和桩周土变形模量的增大而减小,单桩极限承载力和复合地基极限承载力还随三剪统一强度准则中主应力效应参数增大而增大;计算结果与实测资料比较吻合表明本文所提方法有一定的合理性。

Application of the Triple-shear Unified Failure Criterion to the Bearing Performances of the Gravel Pile Composite Foundation

Using the solid cylinder mechanical model for gravel piles and the cylindrical cavity expansion model for surrounding soil, and considering the pile-soil stress transfer and deformation compatibility conditions, the bearing performances of the gravel pile composite foundation are analyzed based on the triple-shear unified failure trite- rion. The pile-soil stress ratio, the ultimate bearing capacities of the single pile and the composite foundation were derived. Example showed that the pile-soil stress ratio decreased with the increasing replacement ratio and the increasing deformation modulus of the soil surrounding. The ultimate bearing capacities of the single pile and the composite foundation increased with the increasing principal stress effective parameter b in the triple-shear unified failure criterion. In addition, the consistence between the calculated results and the experimental data also showed that the method proposed in this paper has certain rationality.