针对地基土体孔隙压缩性导致其变形力学参数变化的特征,对条形基础下地基的非线性沉降计算方法进行改进。首先,通过深入探讨附加应力和应力历史对地基土体模量影响的力学机制,分别建立地基土体变形力学参数随附加应力和应力历史变化的分析模型;然后,利用地基沉降计算的传统分层总和法,考虑地基沉降计算的非线性特征,并引入分级加载的思想,提出条形基础非线性沉降的新型计算方法,该方法不仅反映地基土体变形力学参数随附加荷载变化的特征,也反映地基土体由于初始应力水平或应力历史不同而引起的土体模量不同对地基沉降计算的影响,而且可有效地避免地基沉降计算中压缩试验曲线的使用;最后,通过工程实例计算与分析,并与实测沉降值和其他方法计算结果进行比较,表明方法的合理性与可行性。
According to the variation characteristics of deformation parameters caused by the interstitial compressibility of foundation soils, the nonlinear settlement calculation method of strip foundation is improved. Through further studying the mechanism about the effect of additional stress and stress history on foundation soil modulus, the analytical models that reflect the mechanical deformation parameters of foundation soils which change with additional stress and stress history are established. Then, a new computational method for nonlinear settlement of strip foundation is put forward based on the traditional layer-wise summation method for calculating foundation settlement, in which the nonlinear characteristic of ground settlement calculation and an idea for stepwise loading are incorporated. Consequently, this method not only reflects the characteristics in which the deformation parameters of foundation soils change with additional loads, but also the effect of different soil moduli induced by different initial stress levels or different stress histories on foundation settlement computation. Moreover, the using of the compression test curves in foundation settlement calculation is avoided efficiently. Finally, by comparing the computation and analysis of an engineering example with actually measured and calculated settlements and results by other methods, it is shown that the proposed method is reasonable and feasible.