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

膨胀矿物的膨胀行为模拟是评价膨胀矿物作为封闭材料的性能和进行地下废物处置库设计的必要步骤。研究的目的是建立一个数学模型来描述粘土矿物的膨胀行为，并开发一个新的有限元程序，其中耦合的流体力学过程被纳入到分析应力，位移，吸水量，和体积膨胀/压力建立在膨胀地质材料。通过对基于耦合过程建立的膨胀模型的敏感性分析，讨论了膨胀土弹性模量、持水曲线、渗透系数和扩散系数等重要参数对模型的影响，阐明了膨胀土非线性切线模量的识别方法，其中已经结合了流体机械耦合的横向各向同性行为，B 关于我们 根据自由溶胀试验获得的实验结果。讨论了单轴应变条件下的恒载膨胀试验和自由膨胀试验的结果。研究发现，孔隙比、含水率和饱和度等膨胀特性与应力水平和约束条件密切相关，并通过有限元分析验证了单轴和自由条件下预测的膨胀特性。因为岩体可以预期为围绕由膨胀日组成的人工屏障的第二和天然吸收剂。因此，通过岩石裂隙的渗流模拟可以被认为是至关重要的实现和评价的地下处置库和密封系统的整体稳定性。在本研究中，我们研究了地下水流通过一个单一的岩石裂缝，这是可能的，部分关闭在高岩石应力。流动法则必须不同于平板模型的立方法则，并且必须显示出弯曲。在理论工作的基础上，我们提出了一个适用于部分闭合岩石裂隙的非立方流动法则。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