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

溶胀特性建模是评价溶胀矿物作为密封材料和设计地下废物处置库的必要步骤。本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，其中结合了耦合流体力学程序来分析膨胀地质材料中的应力、位移、吸水和体积膨胀/压力积累。通过对基于耦合流体力学过程建立的膨胀行为模型的敏感性分析，讨论了弹性模量、保水曲线、导水率和扩散系数等公式中几个重要参数的影响。在自由膨胀试验的基础上，进一步研究了溶胀粘土非线性水力学切模量的识别方法，该方法考虑了水力学耦合的横向各向同性。讨论了单轴应变条件下恒载膨胀试验和自由膨胀试验的结果。研究发现，孔隙率、含水率和饱和度的变化与应力水平和/或约束条件密切相关，并通过有限元分析验证了预测的单轴和自由条件下的膨胀行为。必须澄清废物贮存库所在的岩体中裂缝渗流的流体力学，因为岩体可以作为围绕由膨胀日组成的人工屏障的第二天然吸收剂。因此，模拟岩石裂隙渗流对于实现和评价地下储库和密封系统的整体稳定性至关重要。在本研究中，我们研究了地下水通过单一岩石裂缝的流动，该裂缝在高岩石应力下可能部分关闭。流动规律必须不同于面板模型的立方流动规律，并且必须表现出弯曲性。在理论工作的基础上，提出了适用于部分闭合裂隙的非立方流动规律。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