【作者】 鲁祖德；

【导师】 陈从新；

【作者基本信息】 中国科学院研究生院（武汉岩土力学研究所） ， 岩土工程， 2010， 博士

【摘要】 水-岩耦合作用下岩石力学行为的研究是岩土工程领域的基础性前沿课题之一。实际工程岩体总是具有多裂隙的岩体,而裂隙(节理)岩体的安全性往往受到水-岩耦合作用的影响。目前,在水-岩耦合作用下裂隙岩石力学损伤演化规律及变形破裂机理方面的研究还不多,相应的损伤断裂力学本构模型还未真正建立起来。为了着重研究水-岩耦合作用对裂隙岩石强度变形破裂过程的影响机制,通过进行水-岩耦合作用下裂隙岩石的单轴压缩试验和腐蚀时效特征试验、节理强度特性试验和裂隙岩体原位剪切等一系列物理力学试验,分析了水-岩耦合作用下裂隙岩石微裂纹萌生、扩展、贯通及相互作用内部演化过程和力学损伤演化机理,建立了裂隙岩石损伤断裂准则和裂隙岩石破坏过程的本构模型,并对建立的模型进行了对比分析。主要研究内容与成果如下：1.首次在长度为100mm,直径为50mm的真实圆柱形标准试件上加工三种裂纹排列方式的穿透裂纹,所有预制裂纹倾角均为45°,两裂纹岩桥倾角分别为75°和105°。预制裂纹单条长度为10mm,该长度为圆柱形试件上预制裂纹的平面投影长度,最大径向穿透厚度为50mm。人工预制穿透裂纹试件的成功制作并试验,为裂隙岩石变形破坏机理研究提供了新的方法和途径。首次进行了含人工预制穿透裂纹圆柱体标准岩石试件在水-岩化学环境下的力学试验,为水-力学、水-力学-化学耦合过程的研究提供了基础。2.通过进行相同浓度化学溶液不同pH值、不同浸泡流速下的单裂隙与两裂隙红砂岩单轴压缩试验,获得了不同水-岩化学环境下单裂隙和两裂隙岩石试件的应力-应变全过程曲线,并对应力-应变全过程曲线特征进行了分析。探讨了不同水-岩化学环境(浸泡流速、pH值)下对不同预制裂纹排列方式红砂岩变形特性的影响规律与强度腐蚀效应。3.分析了水-岩化学作用下单裂隙与两裂隙岩石的单轴压缩破裂过程与破坏方式,同时分析了两裂隙的裂纹搭接模式与裂纹相互作用机制。基于单轴压缩试验结果,从裂隙岩石的细观结构、化学腐蚀以及损伤断裂三个方面揭示其变形破裂过程及其力学性质损伤演化机理。基于以上单轴压缩损伤机理分析,建立了自然状态和水-岩化学作用下裂隙岩石的损伤演化变量与本构模型,并将本构模型进行应用及对比分析。4.考虑水-岩作用对裂隙岩石的损伤为一个长期的时间效应问题,通过物理手段测试不同浸泡时间段内单裂隙岩石试件与化学反应溶液的相关参数,并进行分析。结果表明,水-岩作用主要是通过水中化学成分与岩石矿物的反应产生的细微观结构与构造化学腐蚀,导致岩石宏观物理力学性质的劣化与变异。5.进行了节理强度特性的水-岩作用试验与损伤本构模型研究。通过三种不同类型岩体结构面在不同饱水状态、不同正应力下的剪切试验研究,分析了水-岩作用对节理剪切力学特性的影响规律,从微观层次上分析了节理在剪切荷载作用下的损伤破坏机制，解释了节理剪切本构关系的非线性和宏观特征。在此基础上加入了水-岩作用对节理的力学损伤效应。借助能量原理,建立了基于损伤的节理剪切应力-应变关系和水-岩作用剪切力学模型。6.进行了不同含水、不同法向应力状态下裂隙岩体的现场直接剪切试验,获得了不同正应力水平下剪切应力-剪切变形关系曲线和剪切强度参数,对其剪切应力-剪切变形关系曲线特征和不同正应力作用下剪应力随正应力的变化规律以及水-力耦合作用对岩裂隙体剪切强度与变形特性影响进行了分析。揭示了含水率对裂隙岩体强度与变形的影响规律,通过试验结果的线性回归建立其定量表征关系即裂隙岩体的粘聚力c与含水率ω具有良好的负指数关系,内摩擦角φ与含水率ω具有近似的对数关系。建立了考虑含水率影响的裂隙岩体抗剪强度准则,并与试验结果进行了对比。最后利用概率统计分析了裂隙岩体的抗剪强度参数指标的变异性。更多还原

【Abstract】 Research on rock mechanical behavior under Water-Rock coupling is one of the most basic forefront issues for geotechnical engineering. Actually engineering rock mass have many cracks, and the safety of fractured rock are affected by Water-Rock coupling. However, at present it’s little research on the mechanical damage evolution and deformation and fracture mechanism of fractured rock under Water-Rock coupling. The corresponding damage and fracture mechanical constitutive model has not yet been established. In order to focus on the research on the effect mechanism of strength and deformation fracture process for fractured rock under Water-Rock coupling, a series of physical and mechanical tests which contained uniaxial compression test and corrosion test and joint strength characteristics test and in situ shear testing have been carried out. The micro-crack initiation, propagation and through and the process of internal evolution and mechanical damage evolution mechanism are analyzed. The damage fracture criterion and the constitutive model have been established. Main research contents and results are as follows:Firstly, for the first time processing arrangement of three pre-cut crack in the length of 100mm,50mm diameter cylindrical standards of the real specimen. All the angle of pre-cut crack are 45°, and the bridge angle of pre-cut two cracks are 75°and 105°. The length of single pre-cut crack is 10mm, and the maximum radial penetration thickness is 50mm. The success of pre-cut crack product and test provide new method and mean for study on rock deformation and fracture mechanism. The first time study on mechanical experiment with the pre-cut crack under Water-Rock Chemical coupling provides the basis for the research on Hydraulic-Mechanics and Hydraulic-Mechanics-Chemical coupling process.Secondly, based on the results of uniaxial compression tests, the characteristics of complete stress-strain curves of cracked rocks under different chemical environment are analyzed, and the behavior of deformation and strength of cracked rocks under different Water-Rock chemical environment(immersion flow rate, pH value) are obtained. Thirdly, failure process and failure modes of uniaxial compression are analyzed, and the modes of crack coalescence and crack interaction mechanism are analyzed. Based on the results of uniaxial compression test, revealed the fractured process and mechanical properties of deformation and fracture mechanism of damage evolution from microstructure, chemical corrosion and damage fracture. Based on the above analysis, damage constitutive model considered Water-Rock chemical coupling is established.Fourthly, the time-dependent characteristics of cracked rocks under different chemical environment are obtained based on the analysis of test data at different time of specimens soaked in different chemical solutions. The results show that Water-Rock Interaction is that meso-structure and construction of chemical corrosion and lead to deterioration and variation of macro physical and mechanical properties.Fifthly, based on the shear test of different joints under Water-Rock coupling, analyzed the joints shear mechanical properties and damage fracture mechanism, explained the nonlinear and macro features of shear constitutive model. With energy principle, joint shear stress-strain relationship based on damage mechanics and shear mechanical model under Water-Rock Interaction are established.Lastly, based on in situ shear test of fractured rock mass under different water contents and normal stress, obtained shear stress-shear deformation curves and shear strength parameters, analyzed the shear stress-shear deformation curves characteristics and variation and effects of shear strength and deformation of fractured rock mass in Hydraulic-Mechanics coupling. It’s revealed that the effect law of fractured rock mass strength and deformation. Fractured rock mass cohesion has a good negative exponential relationship with moisture content, and the angle of internal friction has the approximate logarithmic relationship with moisture content. We concluded from the results that shear strength criteria of fractured rock mass which moisture content was taken into account have been established. Finally, shear strength parameters index variability have been analyzed by using probability and statistics.更多还原