摘要
土体孔隙比对土-水特征曲线(SWCC)具有重要影响。试验研究表明,土体在经历不同水力荷载路径后,孔隙发生胀缩致使SWCC产生滞后现象。基于这一发现,假设孔隙胀缩可致使SWCC曲线及扫描曲线产生滞后现象,并以轴平移技术为例解释了土体孔隙在水力载荷作用下胀缩的细观行为。在此基础上,将由变截面毛细管模型定义的孔隙等效半径与Fredlund-Xing方程相结合,通过将孔径控制参数βd简化为常量,推导得到了考虑孔隙胀缩并能反映滞后效应的非饱和土SWCC增量方程。该模型仅需通过主干燥及任意一条扫描曲线确定模型参数,即可预测其他扫描曲线。最后,通过5组试验数据验证了该模型对不同类型土的适用性且该模型具有预测高阶扫描曲线的能力。
The void ratio of soil has an important influence on the soil-water characteristic curve(SWCC) of unsaturated soil. Experimental studies have shown that pores expand or contract under different hydraulic load paths, which results in the hysteresis of the soil-water characteristic curve(SWCC). Based on this finding, this paper assumes that the expansion and contraction of pores can cause the hysteresis of the soil-water characteristic curve(SWCC). In this study, axial translation technique is employed as an example to explain the expansion and contraction of soil pores under hydraulic loading. Then, an incremental equation for the soil-water characteristic curve that can describe the hysteresis is derived. In this equation, expansion and contraction of pores are calculated by assuming β_d to be a constant and combining the redefined equivalent pore radius with the Fredlund-Xing equation. The proposed soil-water characteristic curve model can be used to predict other scanning curves by simply using the model parameters obtained from the main drying curve and an arbitrary scanning curve. Finally, the applicability of the proposed model to different soil types is verified using five data sets obtained from tests. It is also shown that the proposed model is capable of predicting high-order scanning curves.
作者
陈可
曹文贵
陈贺
CHEN Ke;CAO Wen-gui;CHEN He(College of Civil Engineering,Hunan University,Changsha,Hunan 410082,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2020年第10期3236-3244,共9页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51879104)。
关键词
非饱和土
土-水特征曲线
滞后效应
扫描曲线
孔隙胀缩
unsaturated soil
soil-water characteristic curve
hysteresis effect
scanning curve
pore expansion and contraction