Effective Stress in Unsaturated Silt at Low Degrees of Saturation
Effective Stress in Unsaturated Silt at Low Degrees of Saturation
复制标题
低饱和度非饱和粉土中的有效应力
DOI：
10.2136/vzj2013.06.0109
复制
发表时间：
2014
影响因子：
2.8
通讯作者：
John S. McCartney
中科院分区：
文献类型：
--
作者：
N. A. Alsherif;John S. McCartney
本文提出了一个评估的有效应力的概念，在非饱和，压实粉土在低饱和度。在不同的总吸力和净正应力组合下，对粉土试件进行了等温固结排水三轴试验。使用自动湿度系统控制总吸力，并且在平衡和剪切期间监测的变量包括各向异性体积变化、轴向位移、温度、样品顶部和底部的相对湿度以及样品两端的气压差。通过对三轴试验结果的分析，探讨了用低吸力下的试验数据拟合的土壤持水曲线（SWRC）模型参数预测吸力应力特征曲线（SSCC）的适用性。发现在低吸力下根据SWRC预测的SSCC过度预测了高吸力下的吸力应力值，该吸力应力值是通过失效包络线的后推法获得的，以定义拉伸强度。然而，在SWRC的拟合小的调整，发现提供一个更好的SSCC和实验吸力应力数据之间的拟合。使用调整后的SWRC定义的吸力应力被发现提供了一个很好的解释的临界州线的平均有效应力在高和低吸力范围。
This paper presents an evaluation of the effective stress concept in unsaturated, compacted silt at low degrees of saturation. A set of isothermal, consolidated‐drained triaxial tests was performed on silt specimens under different combinations of total suction and net normal stress. The total suction was controlled using an automated humidity system, and variables monitored during equilibration and shearing include anisotropic volume change, axial displacement, temperature, relative humidity at the top and bottom of the specimen, and the gas pressure difference across the specimen. The results from the triaxial tests were analyzed to examine the applicability of predicting the suction stress characteristic curve (SSCC) using parameters from soil water retention curve (SWRC) models fitted to experimental data obtained at low suction magnitudes. The SSCC predicted from the SWRC at low suctions was found to overpredict the suction stress values at high suctions obtained from back‐extrapolation of the failure envelope to define the tensile strength. However, small adjustments in the fitting of the SWRC were found to provide a better fit between the SSCC and experimental suction stress data. The suction stress defined using the adjusted SWRC was found to provide a good interpretation of the critical state line in terms of mean effective stress over both high and low suction ranges.