摘要
为了更直观和全面地揭示非饱和土的抗剪强度变化规律,针对土体剪切破坏面上抗剪强度与法向应力呈非线性关系以及基质吸力关联摩擦角随基质吸力改变呈非线性变化这两种实验现象,结合vanGenuchten土水特征曲线模型,提出了非饱和土的非线性抗剪强度包络壳模型,进而推导得出了基于土水特征曲线(SWCC)相关参数的非饱和土非线性抗剪强度计算公式。研究表明:模型中各参数较易获取且无须增加额外的试验;与Fredlund包络(平)面模型相比,本文模型参数获取过程更为客观,可有效保证计算的唯一性和准确性;通过与已有文献所给试验结果进行对比分析,本文模型的适用性与可靠性得到了验证,相较于著名的Fredlund非饱和土抗剪强度计算公式,由本文方法给出的非线性抗剪强度与土体真实抗剪强度更为接近。
The aim of this research is to reveal the variation law of shear strength of unsaturated soil more intuitively and comprehensively.Considering that shear resistance develops nonlinearly with normal stress acting on failure surface,as well as matric suction related friction angle varies nonlinearly as matric suction changes,a nonlinear envelope shell model for shear resistance of unsaturated soil is put forward by combining with van Genuchten model.Moreover,a shear resistance calculation method based on soil-water characteristic curve of unsaturated soil is suggested.Research shows that parameters in suggested model can be easily obtained without additional tests.Furthermore,comparing to Fredlund’s envelope plane model,the acquisition process of parameters is more objective,hence the uniqueness and accuracy of the calculation are effectively guaranteed.By comparing with test results given by previous researches,applicability of the suggested model is verified.Furthermore,comparing to the famous formula for shear strength calculation given by Fredlund,the suggested calculation of nonlinear shear strength is closer to the true strength of unsaturated soil.
作者
方薇
李万
曾宪璋
Fang Wei;Li Wan(School of Traffic and Transportation Engineering,Changsha University of Science&Technology,410114,Changsha,China)
出处
《应用力学学报》
CAS
CSCD
北大核心
2019年第5期1220-1226,1266,共8页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金(51408059)
