泥岩渗流—应力—损伤耦合及渗透性自愈合研究

发布时间：2018-04-04 16:32

本文选题：泥岩　切入点：损伤演化　出处：《武汉大学》2014年博士论文

【摘要】：富含粘土矿物的泥岩是介于土和坚硬岩石之间的一种过渡性材料,由于其低渗透性、良好的蠕变性和遇水损伤自修复、高吸附性、较好的地球化学封闭性等特征,被认为是储存核废料的三种备选场地之一。在欧洲,法国、瑞士、比利时等国家都针对泥岩的力学特性和渗透特性开展了系统的研究,并相继建成地下试验平台,进行现场的多场耦合试验。本文将围绕泥岩的弹塑性损伤本构模型、渗流-应力-损伤耦合模型及渗透性自愈合模型等方面开展研究,通过系统的试验研究、理论分析和数值仿真,揭示围岩的损伤演化机理、围岩EDZ的渗透演化机理及渗透性自愈合机理,建立能够描述EDZ开挖扰动效应及自愈合效应的数学模型,为泥岩核废料处置库围岩稳定控制和安全评价提供依据。本论文的主要研究内容如下： (1)对典型泥岩处置库围岩的破坏特征、力学行为特征进行系统地分析,揭示泥岩开挖损伤机制,提出处置库泥岩的破坏准则；借助最小功耗原理,推导能够描述泥岩宏细观破坏特征及力学行为的损伤演化方程,建立弹塑性损伤本构模型。借助ABAQUS软件编写相应的数值仿真程序,验证程序的适用性和正确性,并分析泥岩处置库围岩EDZ受开挖影响的演化规律。 (2)对典型泥岩处置库围岩渗透特征及渗透演化规律进行系统地分析,揭示泥岩渗流动态演化机理；根据泥岩应力-应变过程中的渗透性演化曲线,将泥岩变形破坏过程中的演化曲线分为三个阶段：渗透性降低、渗透性增长及渗透性稳定三个阶段；针对扩容点附近渗透性的突变特征,引入逾渗理论,分析泥岩的渗透性逾渗特征,推导能够描述泥岩宏细观水力学行为的的渗透性演化方程,建立泥岩渗流-应力-损伤耦合模型,将渗流-应力-损伤耦合本构模型嵌入到ABAQUS计算软件中实现了数值仿真计算,利用该模型对某巷道的施工过程进行数值模拟,研究孔隙压力、损伤、渗透系数等的时空演化规律。 (3)系统分析典型处置库泥岩自愈合的室内及现场试验,分析影响自愈合过程的因素及各因素对渗透性的影响规律,得出本文研究所需考虑的泥岩自愈合影响因素,揭示泥岩的自愈合机理,建立渗透性自愈合模型；以ABAQUS为平台进行二次开发,编写相应的数值计算程序,对泥岩巷道的施工过程进行数值模拟,分析自愈合对孔隙压力、损伤、渗透系数等演化规律的影响。 (4)以比利时HADES地下实验室Connecting Gallery为例,结合泥岩力学特性、弹塑性本构模型及渗透性演化模型等研究成果,对Connecting Gallery围岩的应力、变形、孔隙水压力变化、损伤演化规律及渗透性演化规律等进行模拟分析,揭示泥岩核废料处置库的变形破坏机理以及地下水的运移规律,为围岩稳定控制和安全评价提供依据。
[Abstract]:It is considered to be one of three alternative sites for nuclear waste storage.In Europe, France, Switzerland, Belgium and other countries, the mechanical properties and permeability characteristics of mudstone have been systematically studied, and underground test platforms have been built to carry out field multi-field coupling tests.In this paper, the elastoplastic damage constitutive model, seepage stress-damage coupling model and permeability self-healing model of mudstone are studied. Through systematic experimental research, theoretical analysis and numerical simulation,The damage evolution mechanism of surrounding rock, the permeability evolution mechanism and permeability self-healing mechanism of surrounding rock EDZ are revealed, and a mathematical model which can describe the disturbance effect and self-healing effect of EDZ excavation is established.It provides the basis for the stability control and safety evaluation of the surrounding rock in the mudstone nuclear waste disposal depot.The main contents of this thesis are as follows:1) systematically analyzing the failure characteristics and mechanical behavior characteristics of the surrounding rock of typical mudstone disposal reservoir, revealing the damage mechanism of mudstone excavation, putting forward the failure criterion of disposal mudstone, and using the principle of minimum power consumption,The damage evolution equations which can describe the macroscopic failure characteristics and mechanical behavior of mudstone are derived and the elastoplastic damage constitutive model is established.With the help of ABAQUS software, the corresponding numerical simulation program is compiled to verify the applicability and correctness of the program, and to analyze the evolution law of EDZ affected by excavation in the surrounding rock of mudstone disposal reservoir.(2) the seepage characteristics and seepage evolution law of typical mudstone disposal reservoir are systematically analyzed to reveal the dynamic evolution mechanism of mudstone seepage, according to the permeability evolution curve of mudstone stress-strain process,The evolution curve of mudstone deformation and failure is divided into three stages: permeability reduction, permeability growth and permeability stability.The permeability percolation characteristic of mudstone is analyzed, the permeability evolution equation which can describe the macroscopical hydraulic behavior of mudstone is deduced, and the coupled model of seepage, stress-damage is established.The coupled constitutive model of seepage stress and damage is embedded into ABAQUS software to realize numerical simulation. The model is used to simulate the construction process of a roadway to study pore pressure and damage.The temporal and spatial evolution of permeability coefficient and so on.3) systematically analyzing the laboratory and field tests of mudstone self-healing in typical disposal reservoir, analyzing the factors affecting self-healing process and the influence law of each factor on permeability, and obtaining the influencing factors of mudstone self-healing that need to be considered in this paper.The self-healing mechanism of mudstone is revealed, the permeability self-healing model is established, the secondary development is carried out on the platform of ABAQUS, the corresponding numerical calculation program is compiled, the construction process of mudstone roadway is numerically simulated, and the pore pressure and damage caused by self-healing are analyzed.The influence of the evolution law such as permeability coefficient.Taking Connecting Gallery of HADES underground laboratory in Belgium as an example, combining with the mechanical properties of mudstone, elastoplastic constitutive model and permeability evolution model, the changes of stress, deformation and pore water pressure of Connecting Gallery surrounding rock are studied.The damage evolution law and permeability evolution law are simulated and analyzed to reveal the mechanism of deformation and failure of mudstone nuclear waste disposal depot and the law of groundwater migration, which provides the basis for the stability control and safety evaluation of surrounding rock.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU45;TV139.1

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