Physicochemical and and hydromechanical behaviors of clay sulfate rocks and soils -Application study for sealing systems of underground waste repository -

膨胀行为的模拟是评价膨胀矿物作为封堵材料和地下垃圾处置库设计的必要步骤。本研究的目的是建立描述粘土矿物膨胀行为的数学模型，并开发一种新的有限元程序，其中包括耦合流体力学过程来分析膨胀地质材料中的应力、位移、吸水量和体积膨胀/压力聚集。通过对基于流体力学耦合过程建立的膨胀特性模型的灵敏度分析，讨论了弹性模数、持水曲线、渗透系数和扩散系数公式中几个重要参数的影响，并阐明了考虑水-力耦合横向各向同性特性的膨胀土非线性水力学切线模数的识别方法，b…更多地基于自由溶胀试验所获得的实验结果。对单轴应变恒载膨胀试验和自由膨胀试验结果进行了讨论。研究发现，孔隙率、含水率和饱和度的变化等溶胀行为强烈依赖于应力水平和/或约束条件，并通过有限元分析验证了预测的单轴和自由条件下的溶胀行为。必须阐明废物库所在的岩体内裂隙渗流的流体力学，因为岩体可以被认为是由溶胀日组成的人工屏障周围的第二和自然吸水剂。因此，建立岩石裂隙渗流模型对于实现和评价地下储存库和封堵系统的整体稳定性是至关重要的。在目前的研究中，我们研究了通过单一岩石裂隙的地下水流动，在高岩石应力下，裂隙可能部分闭合。其流动规律必须不同于面板模型的立方流动规律，并且必须表现出曲折性。在理论工作的基础上，提出了一种适用于部分闭合岩石裂隙的非立方体渗流规律。较少

The modeling of swelling behavior is a necessary step to evaluate swelling minerals as sealing materials and to design underground waste repository. The purpose of the study is to construct a mathematical model to describe the swelling behaviors of clay minerals and to develop a new FEM program in which a coupled hydromechanical procedure is incorporated to analyze stresses, displacements, water uptakes, and volumetric expansions/pressure build-ups in swelling geological materials. Through the sensitivity analysis on the model of swelling behaviors constructed on the basis of the coupled-hydromechanical procedure, the influence of several important parameters involved in the formulae of elastic modulus, water retention curve, hydraulic conductivity and/or diffusivity, was discussed.Additionally, the method to identify the nonlinear hydromechanical tangent moduli of swelling clay was clarified, in which transversely isotropic behavior of hydromechanical coupling has been incorporated, b … More ased on the experimental results obtained by free swelling tests. The experimental results of constant load swelling tests in uniaxial strain condition and free swelling tests were discussed. We find that swelling behaviors such as changes of void ratio, water content ratio, and saturation depend strongly on stress level and/or constrained conditions, and verify the predicted swelling behaviors in uniaxial and free conditions by using finite element analysis.The hydromechanics of seepage flows through fractures within rock mass, where a waste repository is situated, must be clarified, since the rock mass can be expected as second and natural absorbents surrounding an artificial barrier composed of swelling day. Therefore, modeling the seepage flows through rock fractures can be regarded as crucial for achieving and evaluating overall stability of an underground repository and sealing systems. In the present study, we have studied groundwater flow through a single rock fracture, which is possible to be partially closed under high rock stresses. The flow rule must be different from the cubic one of a panel plate model and it must show the tortuosity. Based on a theoretical work, we have proposed a non-cubic flow rule, which can be applicable to partially closed rock fractures. Less