【作者】 余丽；

【导师】 扶名福；

【作者基本信息】 南昌大学 ， 固体力学， 2013， 博士

【摘要】 裂隙岩体是岩体工程最普遍的施工对象之一。由于工程施工的扰动,岩体原有的平衡状态被打破,由此引起岩体内的应力重分布,促使岩体中内在裂纹(裂隙)不断累积和发展,进而产生宏观的时效断裂,导致岩体发生破坏失稳。在实际工程中边坡稳定计算、变形等多数考虑的是加载理论,往往岩体卸荷裂隙是影响边坡岩体稳定性的重要因素。本文首先揭示了裂隙岩体在卸荷状态下裂隙岩体本构关系的各个阶段的力学机理,运用半反推法建立了卸荷岩体分别在小变形和大变形初值问题的以σij、uij或σij、εij为二类变量变分原理。在建立变分原理的基础上以引入拉氏乘子的方法将变分约束条件加入到能量泛函中从而导出广义变分原理,因此分别建立卸荷裂隙岩体在小变形和大变形以σij、εij或σij、εij为变量的广义变分原理能量泛函。根据Vananis提出的内时本构基础理论是依赖于材料的性质和变形历史,是用来描述整个变形和温度的历史功能的历史依赖性的力学响应。裂隙岩体是非线性材料,建立卸荷裂隙岩体在初级阶段的内时本构关系,并将理论值与实验值测得的应力应变进行比较,验证了内时变分理论在卸荷裂隙岩体初级阶段应用的正确性。结合以井冈山某工程为例,该工程在开挖过程中有地裂缝出现,首先对该实际工程中岩体出现的裂缝进行勘察。根据高密度电法原理查明了地裂缝的延伸范围、发育深度及裂面倾斜方向等要素并分析其形成原因,为实际工程提出相关建议和措施。运用分析软件ABAQUS一方面对井冈山某工程开挖后的下部边坡在考虑不同工况(天然状态下、降雨后、地震作用、新建建筑物建成后等)下建立计算模型,输入场地材料参数,进行边坡稳定性计算分析,计算出不同工况下的稳定系数,评价了该场地的稳定性。结合卸荷理论考虑井冈山某工程上部边坡开挖即卸荷过程对下部边坡的影响,选择开挖过程中含地裂缝的稳定性等综合因素较差的边坡作为原型,建立相应的ABAQUS计算模型,模拟开挖过程的卸荷情况,考查分析在开挖过程中地裂缝的应力应变的变化规律及与卸荷裂隙岩体的内时本构理论比较,发现在地裂缝的左右两侧应力应变呈现不同的变化规律,为实际工程提供一定的理论依据,将内时理论的应用进一步扩展。更多还原

【Abstract】 Fractured rock mass is one of the most common rocks engineering construction objects. Due to the disturbance of the construction, the original rock mass balance is broken, which causes redistribution of stress in the rock mass, procures the continuous accumulation and development of the inherent cracks (fissures) in the rock mass, produces macro-aging fracture, and leads to instability of rock mass destruction. In the actual project, most consideration is given to rock-loading theory in slope stability calculation and deformation, and often, the rock-unloading is an important factor affecting the stability of rock slope.The various stages mechanical mechanism of fractured rock mass constitutive relation under unloading condition is first revealed in this dissertation. The variational principle of unloading rock mass with σij、uij or σij、εij as second type variables in the initial value problems of both small deformation and large deformation is established through the usage of semi-inverse method. The corresponding energy functional is derived.On the basis of establishing the variation principle, the variational constraint conditions are added to the energy functional through the method of introducing the Lagrange multiplier, which further derives the generalized variation principle. Therefore, the generalized variation principle energy functional of unloading fractured rock mass with Cy σij、uij or σij、εij as second type variables in small deformation and large deformation were established.According to the endochronic constitutive basic theory by Vananis which depends on the material properties and deformation history and is used to describe the history dependence mechanical response of the entire deformation and temperature history function. Fractured rock mass is non-linear material; Building up endochronic constitutive relation of the unloading fractured rock mass in the primary stage and making comparison between the theoretical and experimental values verify the correctness of the application of endochronic theory in the primary stage of the the fractured rock mass. Take Jinggangshan project for example, the ground fissures appeared in the excavation process and cracks of rock mass in the Engineering were surveyed to explore the cracks features. According to the high-density electrical method principle, extending scope and development depth of the ground fissures, tilt direction of crack surface and other factors have been investigated and reasons for its formation were analyzed. Some relevant recommendations and measures had been proposed for the practical engineering.By using the analysis software ABAQUS, on the one hand, different conditions (natural state, after the rainfall, after the earthquake, after the completion of the new buildings) are taken into account to establish computational model for the lower part of the slope after excavation in the Jinggangshan project. On the other hand, ground material parameters were input to calculate and analyze the Slope stability. Stability factor was calculated under different conditions and the stability of the site was evaluated.In Combination with the unloading theory, considering that the upper slope excavation influences the lower part during the unloading process in the Jinggangshan Engineering, choosing the poor slope with factors containing cracks stability as the computational model in the excavation process.building the corresponding ABAQUS calculation model, Simulating excavation unloading process, analyzing the variation of the stress-strain during excavation cracks and making comparison between the calculated data and the theoretical value of endochronic constitutive theory provide a theoretical basis for practical engineering and make a further expansion for the application of the endochronic theory.更多还原