基于双剪统一强度理论的碎石桩复合地基承载及变形性状研究

Research of Bearing and Deformation Character for Composite Foundation with Granular Column Based on the Twin Shear Unified Strength Theory

基于双剪统一强度理论,并利用复合地基中碎石桩与桩周土的竖向位移相等,侧向变形协调与连续的条件,通过弹塑性理论,对碎石桩复合地基的承载及变形性状进行了分析研究,讨论了权系数b的大小对复合地基承载及变形性状的影响,推出了作用在复合地基上的荷载、碎石桩所分担的荷载及加固区压缩量与桩周土的塑性区半径的关系的系列解析算式。提出了对于碎石桩复合地基的设计应该实行承载力和沉降双重控制的设计思想。为验证本方法的可行性,将模型试验的结果与计算结果进行了对比。

Based on the twin shear unified strength theory, and using vertical deformation equality, lateral deformation harmony and continuum between granular column and surrounding pile soil in the composite foundation, bearing and deformation character of the composite foundation with granular columns is analyzed by the elastic-plastic theory. Influences of weight coefficient b on bearing and deformation character of the composite foundation are discussed,A series of analytical formulae, for example, between load exerted on the composite foundation or distributive load of granular column or compression value of the reinforcement area and plastic area radius of surrounding pile soil, are drived. Design idea of double control on bearing capacity and settlement is suggested for the composite foundation with granular columns. To make sure feasibility of the proposed method, results of model tests are compared with those of calculation. Comparison indicates that the proposed method in this paper is of guiding significance for the composite foundation design with granular columns.