【作者】 邓建华；

【导师】 黄醒春；

【作者基本信息】 上海交通大学 ， 结构工程， 2010， 博士

【摘要】 膏溶角砾岩是一类富含粘土矿物的水敏感性岩体,其强度遇水迅速降低这一特点对该类岩石在隧道工程中的应用具有十分重要的影响,它的强度和变形特征,将直接关系着工程设计、施工和运营的稳定性。本文在室内膨胀试验和强度试验的基础上,对膏溶角砾岩的膨胀特性和力学特性进行了比较系统的研究,并通过微观观测对膏溶角砾岩中水-岩相互作用的微观机理进行了探讨,取得了以下部分结果:通过膨胀试验,得出了膏溶角砾岩的膨胀力和膨胀应变的变化规律,提出了Hunder-Amberg修正模型。在此基础上引入时间因素,建立了膏溶角砾岩的时变膨胀本构关系。通过单轴和三轴试验获得了膏溶角砾岩在不同含水量、不同围压下的应力-应变曲线特征、变形及强度参数;总结了膏溶角砾岩的应力-应变曲线、弹性模量及强度随围压和含水量的变化规律,以及含水量对脆延转换的影响。通过粉晶x衍射、电子扫描电镜等微观试验,研究了水对膏溶角砾岩的微观结构的影响,探讨了水在膏溶角砾岩的赋存方式,从力学作用、物理作用、化学作用等方面分析了水-岩相互作用的机理,在此基础上建立了膏溶角砾岩的水损伤模型。结合以上试验结果,对自由能、比自由能的重新定义,并在热力学的基础上,引入水的损伤,将水和力产生的损伤耦合起来,建立了考虑膨胀和损伤影响的膏溶角砾岩的弹塑性本构模型。该模型能很好地模拟岩石应力-应变的峰后曲线。本文在试验方面详细研究了膏溶角砾岩的膨胀和力学特性,建立了膏溶角砾岩的膨胀模型和水损伤模型;在理论方面,通过对自由能、比自由能的重新定义,建立了考虑膨胀影响的膏溶角砾岩弹塑性本构模型。本文的研究成果可为类似于膏溶角砾岩这样的水敏感性岩石地层中的设计、施工和运营提供参考。更多还原

【Abstract】 Gypsum breccia is a type of water-sensitive rock rich in clay. The strength of gypsum breccia decreases rapidly while meeting water, which is critical to the design, construction and maintenance of relevant projects.Based on the strength and swelling tests, the swelling characteristics and the mechanical properties of this rock are investigated. The microcosmic mechanism of Water-Rock Interaction(WRI) in gypsum breccia is addressed through microscopic observation. The main research contents are listed as follows:According to the swelling test, the change patterns between the swelling stress and the strain of gypsum breccia are obtained, and the improved Hunder-Amberg model is proposed. After that, a constitutive law describing one-dimensional unstable expansion is established by introducing the time factor.By the uniaxial and triaxial compression tests, the stress-strain curve, the deformation and strength parameters of gypsum breccia with different initial water contents and different confining pressures are determined, and the change patterns are generalized. The effect of the water content on the brittle-ductile transformation is analyzed.With the micro-measurement methods, SEM and XRD, the existing forms of water molecules, that have an influence on the microstructure in gypsum breccia is studied. The mechanism of water-rock interaction is analyzed in the mechanics, physics and chemistry ways. Last, a water damage model is developed.From the above results, the re-definition of the free energy and the specific free energy and the introduction of water damage, based on thermodynamics and continuum damage mechanics, the elastic-plastic constitutive model of gypsum breccia considering expansion and damage, are given. Using this model proposed, the rock stress-strain curve after the peak can be simulated well.To sum up, the swelling characteristics and the mechanical properties of gypsum breccia are detailedly studied through experiments. The swelling models and the water damage model are established. After the free energy and the specific free energy are re-defined in theory, the elastic-plastic constitutive model of gypsum breccia considering expansion and damage are built. The results obtained here are also applicable to water-sensitive rocks which characteristics are similar to gypsum breccia.更多还原