变荷载下层状非饱和土地基全耦合固结特性研究  

Fully-coupled consolidation characteristics of layered unsaturated soils subjected to varying loadings

作　　者：叶梓 艾智勇[1,2] YE Zi;AI Zhi-yong(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩土力学》2021年第1期135-142,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.50578121,No.41672275)。

摘　　要：非饱和土是地球表层土体一种常见的存在形式。与经典的饱和土Biot固结理论相比,非饱和土固结理论还亟待发展。基于Fredlund非饱和土双应力变量固结理论,放弃传统理论固结过程中骨架总应力不变的假设,推导出变荷载作用下非饱和土全耦合轴对称固结理论的控制方程组。通过Laplace-Hankel变换处理变量t和r,所得的控制方程被处理为常微分方程组;扩展的精细积分法将被进一步运用求解方程组以得到层状非饱和土地基在变换域内的固结解答,而最终的解答将通过Laplace-Hankel逆变换技术求得。将非饱和土地基退化为饱和土地基,与现有文献结果进行对比,验证所提方法结果的可靠性;最后,提供3个数值算例,以讨论加载时间T0、孔隙水关于净应力的体积变化系数m1w以及土体分层性对非饱和土固结特性的影响。Soils are commonly existing in unsaturated condition on the earth’s surface. Compared with the classic Biot consolidation theory for saturated soils, the consolidation theory of unsaturated soils is still largely unexplored. Based on the Fredlund’s double stress variables consolidation theory of unsaturated soils, this paper derives the governing equations of axisymmetric fully-coupled consolidation of unsaturated soils under varying loadings, by removing the assumption that the total stress remains unchanged during the consolidation. With the aid of Laplace-Hankel transform, the governing equations are converted into ordinary differential equations by eliminate the variables r and t. The extended precise integration method is further applied to solve these equations and obtain solutions of layered unsaturated soils in the transformed domain. The actual solutions are acquired by the inverse Laplace-Hankel transform technique. The feasibility of the presented results is further verified by comparing with those of degenerated saturated soils in the existing literature. At last, three numerical examples are provided to investigate the influence of varying ramp time T0, varying coefficients of the water volume change due to the net normal stress m1w and the stratification on the consolidation characteristics of unsaturated soils.

关 键 词：层状非饱和模型 全耦合 变荷载 固结特性 精细积分法 

分 类 号：TU470[建筑科学—结构工程]