Impacts of saturation-dependent anisotropy on the shrinkage behavior of clay rocks
Impacts of saturation-dependent anisotropy on the shrinkage behavior of clay rocks
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DOI：
10.1007/s11440-021-01268-9
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发表时间：
2021-07
期刊：
影响因子：
5.7
通讯作者：
S. C. Ip;J. Choo;R. Borja
中科院分区：
文献类型：
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作者：
S. C. Ip;J. Choo;R. Borja
由于矿物颗粒和/或裂缝的优先取向，土壤和岩石等岩土材料可能表现出固有的各向异性。它们也可以被占据孔隙空间的多种类型的流体部分饱和。岩土材料的各向异性和非饱和特性可能是高度相互依赖的。实验研究表明，岩石的弹性参数随饱和度的变化而变化。在横观各向同性粘土岩中，饱和度的影响也因方向不同而不同。这导致了与饱和度相关的刚度各向异性。同样，渗透率各向异性也可以依赖于饱和度。在这项研究中，给出了考虑饱和相关刚度和水力各向异性的本构方程。弹性参数与饱和度的关系用线性函数来描述，相对渗透率与饱和度的关系用对数线性函数来描述。将这些方程应用到流体力学框架中，以研究与饱和度相关的特性对粘土岩收缩行为的影响。数值模拟表明，饱和度相关的刚度和水力各向异性在收缩行为中的作用。结果表明，孔压的应变各向异性和时间演化主要受饱和度相关的刚度和水力各向异性的影响。
Geomaterials such as soils and rocks can exhibit inherent anisotropy due to the preferred orientation of mineral grains and/or cracks. They can also be partially saturated with multiple types of fluids occupying the pore space. The anisotropic and unsaturated behaviors of geomaterials can be highly interdependent. Experimental studies have shown that the elastic parameters of rocks evolve with saturation. The effect of saturation has also been shown to differ between directions in transversely isotropic clay rock. This gives rise to saturation-dependent stiffness anisotropy. Similarly, permeability anisotropy can also be saturation-dependent. In this study, constitutive equations accommodating saturation-dependent stiffness and hydraulic anisotropy are presented. A linear function is used to describe the relationship between the elastic parameters and saturation, while the relative permeability–saturation relationship is characterized with a log-linear function. These equations are implemented into a hydromechanical framework to investigate the effects of saturation-dependent properties on the shrinkage behavior of clay rocks. Numerical simulations are presented to demonstrate the role of saturation-dependent stiffness and hydraulic anisotropy in shrinkage behavior. The results highlight that strain anisotropy and time evolution of pore pressures are substantially influenced by saturation-dependent stiffness and hydraulic anisotropy.