考虑施工扰动和荷载效应的复合地基固结解
Theoretical solution for consolidation of composite foundations considering construction disturbance and loading effect
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摘要: 在等应变条件下,考虑了土体水平渗透系数受到桩体施工的扰动而沿着径向逐渐变化和地基中的附加应力沿深度线性分布的特点,采用由平衡条件和等应变假设得到的新的初始条件,给出了土体和桩体的超静孔压解,并分别给出复合地基按应力和按变形定义的总平均固结度。最后分析了附加应力分布形式、扰动区大小及扰动区土体渗透系数的变化对地基固结性状的影响,并将本文结果和已有的结果做了比较。结果表明:按应力和按变形定义的地基的总平均固结度相等;地基的固结随着地基顶面和底面处的附加应力之比的增大而加快,当附加应力呈倒三角分布时固结最快,正三角最慢;扰动区越大或者扰动区土体渗透系数沿径向减小的越快,固结越慢。Abstract: Under the condition of equal strain,using a new initial condition derived from equilibrium equations and equal strain assumption,and considering the gradual variation of horizontal permeability of disturbed soils and the change of the total stress with depth in composite foundations,the excess hydrostatic pressures in the column and the surrounding soil were obtained and the overall average consolidation rates defined in terms of stress and deformation were given.Finally,the influences of several factors,such as the distribution of the total stress in composite foundation,the size of disturbed zone and the variation of the horizontal permeability of soils on the consolidation of composite foundation were analyzed.The results showed that the solution of overall average consolidation rate in terms of stress was equal to that in terms of deformation;the consolidation of composite foundations was accelerated with the increase in the ratio of top total stresses to the bottom total stress in the composite foundation;the consolidation rate was at its maximum when the total stress distributes in the form of a triangle and at its minimum when the total stress distributes in the form of a reversed-triangle;the larger the smeared zone was or the faster the horizontal permeability of soils decreases with radial distance away from column,the slower the consolidation rate was.