摘要
结合室内固结渗透联合试验资料,考虑实际中的变荷载以及地基中初始有效应力的真实分布,建立基于指数形式渗流定律的一维非线性固结方程,并得到其差分数值解。在指数形式渗流定律退化为达西定律的前提下,将变荷载下假定初始有效应力沿深度均匀分布和固结系数保持不变的解析解与相应的差分解进行对比,验证差分解的可靠性。在此基础上,分析不同参数下的非线性固结性状。结果表明:最终有效应力与初始有效应力平均值的比值较小(≤2)时,随着渗流定律中指数的增加,在较小时间因子下固结速率会加快,而在较大时间因子下会变慢;但是随着最终有效应力与初始有效应力平均值比值的增大,固结曲线在全过程中均会表现出随着指数的增加固结速率加快的性状;初始有效应力沿深度线性增加下的固结速率要比均匀分布下的固结速率快;变荷载的加荷速率越快则固结速率也越快。此外,最终有效应力与初始有效应力平均值的比值以及描述土体非线性固结特性的参数均对非线性固结性状有较大影响。
Based on the results of consolidation experiments combining with permeability test, the governing equation of nonlinear consolidation was developed to consider exponential flow law, time-dependent loading and the actual distribution of initial effective stress in actual engineering, and the finite difference solutions for this governing equation were obtained. On condition that exponential flow law was degenerated to Darcy＇s law, constant coefficient of consolidation, time-dependent loading and uniform distribution of initial effective stress were considered, the reliability of numerical solutions was verified by comparing the numerical solutions with the corresponding analytical solutions. Furthermore, nonlinear consolidation behavior under different parameters was analyzed. The results show that, if the ratio of the final effective stress to the average value of initial effective stress is less than 2, the rate of consolidation increases under smaller time factor, and decreases under the large long time factor. With the ratio of the final effective stress to the average value of initial effective stress increases, it can be found from the consolidation curves that the rate of consolidation increases with the exponent during the whole process of consolidation. The rate of consolidation with consideration of linear increases of initial effective stress is faster than that with consideration of uniform distribution of initial effective stress. The rate of consolidation increases with loading rate. In addition, both the ratio of the final effective stress to the average value of initial stress and the nonlinear consolidation parameters have greatly influenced on consolidation behavior.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2012年第A01期3270-3277,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(51109092
50878191)
湖南省哲学社科基金项目(11YBA183)
关键词
土力学
指数形式渗流定律
变荷载
非线性固结
初始有效应力真实分布
有限差分法
soil mechanics
exponential flow law
time-dependent loading
nonlinear consolidation
actualdistribution of initial effective stress~ finite difference method
