【作者】 杨文东；

【导师】 张强勇；

【作者基本信息】 山东大学 ， 岩土工程， 2011， 博士

【摘要】 高坝出现较大变形与破坏,在很大程度上与坝基软弱岩带和硬脆性岩体在长期荷载作用下产生流变变形密切相关。本文以大岗山水电站坝区的硬脆性辉绿岩和软弱岩带为研究对象,采用试验研究、理论分析和数值模拟相结合的研究方法,基于硬脆性岩石的室内三轴流变试验结果和软弱岩带的现场大型刚性承压板压缩蠕变试验结果,运用非线性流变理论以及损伤力学理论探讨岩石流变力学特性,建立岩石的非线性流变本构模型,用以预测水电站坝区边坡工程的长期变形特性。本文主要研究成果包括以下几个方面：(1)采用全自动岩石三轴流变伺服仪,对大岗山水电站坝区的硬脆性辉绿岩进行了不同应力路径下的三轴流变试验研究,分析了辉绿岩三轴流变过程中的变形特性,选取典型岩样进行了破坏断口的电镜扫描试验分析,考察了辉绿岩细观结构变化对其宏观强度的影响,揭示了复杂应力状态下辉绿岩的流变破坏机理。(2)结合现场软弱岩带的大型刚性承压板压缩蠕变试验,推导了刚、柔性承压板压缩蠕变试验的黏弹性变形理论解析公式,为蠕变参数的理论反演奠定了基础。(3)基于辉绿岩三轴流变试验的变形特征,建立了一个新的非线性黏弹塑性流变模型,提出用屈服接近度作为三维蠕变分段函数的判别标准,该模型可以很好地描述岩石的衰减蠕变、等速蠕变特别是加速蠕变的三阶段蠕变变形。(4)基于软弱岩带的现场刚性承压板压缩蠕变试验的变形特征,建立了一个材料参数随时间逐渐劣化的变参数损伤流变模型,可以反映软弱岩带的黏弹、黏塑和损伤变形特性。(5)将本文提出的硬脆性辉绿岩的非线性黏弹塑流变模型和软弱岩带的变参数损伤流变模型进行了程序编制。(6)将改进的二次粒子群算法(PSO)嵌入到流变参数反演程序中,实现了流变参数的快速智能反分析,并通过数值反演法获得了辉绿岩脉软弱岩带的流变力学参数。(7)提出了通过三轴流变体积应变法和加卸载流变试验的残余应变法确定硬脆性岩石长期强度的适用方法。(8)采用本文提出的硬脆性岩石的非线性黏弹塑流变模型和软弱岩带的变参数损伤流变模型进行了大岗山水电站坝区边坡的三维开挖流变数值计算,预测复杂应力状态下岩体工程的开挖流变特性。更多还原

【Abstract】 The large deformation and failure of high dam was closed to the rheological deformation of weak intercalated rock mass and hard brittle rock mass in dam foundation under long-term loads. The hard brittle diabase and weak intercalated rock mass in dam foundation of Dagangshan hydropower station were taken for research object, the research methods combined of experiment, theoretical analysis and numerical simulation were used. Based on the triaxial rheological experiment results of hard brittle rock in laboratory and in-situ compressive creep test results under large rigid bearing plate of weak intercalated rock mass, the rheological mechanical properties of rock was analysed by use of nonlinear rheological theory and damage mechanics. Nonlinear rheological constitutive models of rock were established, and the long-term stability of slope project in dam zone of hydropower station was predicted.The main research work focused on the following.(1) In order to know about the rheological properties of rock specimens in Dagangshan hyeropower project, triaxial compression rheological experiments with rock specimens under different stress load paths were carried out on the rock servo-controlling rheology testing machine. The deformation characteristics in triaxial rheological process were discussed in detail. The SEM experiments were carried out for typical fracture shaping of rock specimens, the influence of rock mesoscopic structure change on its macroscopic strength was studied, and the rheological fracture mechanism of rock under complex stress states was put forward.(2) Based on in-situ compressive creep tests under rigid bearing plate, theory analytical formulas’method for inversion of visco-elastic compressive creep parameters under rigid or flexible plate was established. The rheology parameters were obtained through the combination of theoretical analytic inversion and the experiment data.(3) Based on deformation characteristics of specimens in the triaxial rheological experiments, a new nonlinear visco-elasto-plastic rheological model was established which could describe the primary creep, steady-state creep and tertiary creep perfectly, and the yield approach index(YAI) was taken as the discriminant criteria of piecewise function in three dimensional creep equation.(4) Based on deformation characteristics of in-situ compressive creep tests under rigid bearing plate, a nonlinear damage rheological model was proposed in which the creep parameters of the weak intercalated rock mass were weakened with time gradually, and this model could describe the visco-elastic deformation, visco-plastic deformation and damage deformation perfectly.(5) Secondary development of nonlinear visco-elasto-plastic rheological model for hard brittle rock and nonlinear rheological damage model for weak intercalated rock mass were carried out in FLAC3D.(6) The improved Particle Swarm Algorithm(PSO) was programmed for the rheological parameters inversion, which achieved rheological parameters rapidly and intelligently through back analysis. The rheological parameters of weak intercalated rock mass were got by numerical calculation inversion method.(7) The triaxial rheological volume strain method and residual strain method in loading-unloading rheological test were put forward to determine the long-term strength of hard brittle rock.(8) By using the nonlinear visco-elasto-plastic rheological model of hard brittle rock and variable parameters-based damage rheological model of weak intercalated rock mass,3D excavation and rheological numerical calculation of slope in dam zone of Dagangshan hydropower station was carried out, which predicted the long-term deformation characteristic after excavation of rock engineering in complex stress state.更多还原