A new hollow cylinder triaxial cell to study the behavior of geo-materials with low permeability
A new hollow cylinder triaxial cell to study the behavior of geo-materials with low permeability
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DOI：
10.1016/j.ijrmms.2011.02.017
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发表时间：
2011-06
影响因子：
7.2
通讯作者：
M. Monfared;P. Delage;J. Sulem;M. Mohajerani;A. Tang;E. Laure
中科院分区：
文献类型：
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作者：
M. Monfared;P. Delage;J. Sulem;M. Mohajerani;A. Tang;E. Laure
设计了一种新型的空心圆柱形三轴试验箱（内径60 mm，外径100 mm），用于研究低渗透饱和岩土材料（如硬粘土或粘土岩）在控制温度和孔压条件下的力学行为。该装置的主要优点是中空圆柱体几何形状允许的短排水路径，其厚度减少到样品厚度的一半（10 mm）-比78 mm高的标准完整圆柱体样品的厚度小四倍。与传统的完整圆柱形样品相比，减少的排水路径允许初始不饱和样品的显著更快的再饱和过程。它还允许以较高的加载速率实现排水条件（即测试期间可忽略的超孔隙压力）。饱和过程的数值模拟表明，空心圆柱体粘土样品的再饱和可以实现几乎30倍的速度比标准的完整的样品，在一端排水，约7倍的速度比在两端排水的样品。本文还根据各向同性压缩试验的数值模拟结果，讨论了在硬粘土和粘土的排水试验中应采用的适当加载速率。分析了排水系统变形能力对不排水试验中实测参数的影响。在Bishop工作的基础上，考虑多孔单元和排水系统的变形能力，提出了一种修正方法。
A new hollow cylinder triaxial cell (60mm internal diameter and 100mm external diameter) has been designed to study the behavior of low permeability saturated geo-materials such as stiff clays or argillites under controlled temperature and pore pressure conditions. The main advantage of this device is the short drainage path allowed by the hollow cylinder geometry that is reduced to half the thickness of the sample (10mm)—four times less than that of standard full cylinder samples of 78mm height. The reduced drainage path allows a significantly faster resaturation procedure of initially unsaturated samples compared to conventional full cylindrical samples. It also permits the achievement of drained conditions (i.e. negligible excess pore pressure during testing) with a higher loading rate. A numerical simulation of the saturation process demonstrates that the resaturation of the hollow cylinder clay sample can be achieved almost 30 times faster than in standard full samples that are drained at one end, and about seven times faster than in samples drained at both ends. Appropriate loading rates to be used in drained tests on stiff clays and argillites are also discussed based on a numerical simulation of the isotropic compression test. The effect of the deformability of the drainage system on the measured parameters during undrained tests is also analyzed. A correction method is proposed, based on the work of Bishop, by considering the deformability of the porous elements and of the drainage system.