【作者】 杨静；

【导师】 何江达；

【作者基本信息】 四川大学 ， 岩土工程， 2003， 硕士

【摘要】 锦屏一级水电站位于四川省盐源县和木里县境内，是雅砻江干流上的重要梯级电站。电站设计装机容量3300MW，采用混凝土抛物型双曲拱坝，最大坝高305.0m，是拟建的国际上最高拱坝。无论是对大坝还是对地下厂房洞室群的稳定而言，地应力场的研究都具有非常重要的意义，同时，大坝基础开挖后形成的300m级高边坡稳定问题也是一个有待深入研究的课题。 本文根据锦屏一级水电站坝址区的地形地质特性，运用三维非线性有限元仿真计算方法，对坝址区初始地应力场和坝肩槽开挖高边坡的稳定性及工程加固措施开展了系统研究。 首先结合锦屏一级水电站坝址区的地形地质条件与地应力实测资料，运用三维有限元回归分析方法，建立工程区域的三维初始地应力场且真实反映坝址区地质构造的有限元模型，并用逐步回归方法探讨了地应力场的待回归因素与构造应力场的模拟方式，对比分析了两种回归方案的特点，为坝肩槽开挖高边坡和地下厂房洞室群围岩稳定性分析提供合理的初始地应力场。 在确定的坝址区初始地应力场条件下，采用三维非线性有限元的仿真技术，模拟左右岸坝肩槽分级开挖过程，研究了岩质边坡的卸荷效应，以及应力、位移和点安全系数的分布规律，揭示了边坡可能出现的破坏部位与发育程度。在此基础上提出了相应的加固处理措施，并研究了加固措施的工程效应，论证了工程加固措施的合理性与可靠性。 本文的特色在于：(1)针对锦屏水电站工程坝区地形地质条件，建模时充分考虑了坝址区内的断层、深部裂缝以及节理裂隙的分布特性，客观地反映了工程的实际情况；(2)在地应力场回归分析计算时，对构造应力场的模拟方 摘要式作了探讨与新的尝试，引入剪切位移模拟地质构造作用对主应力方向的调整作用，采用逐步回归的方法来选择待回归因素，讨论了岩体自重应力场在初始地应力场中的权重问题，并考虑了两种地应力场回归方案，综合评价了各自的特点;(3)在三维非线性有限元仿真计算中，考虑了岩体的Drucke二Prager弹塑性模型和遍布节理的定向破坏模型，研究分级开挖过程中坝肩槽边坡岩体的应力场、位移场及破坏信息分布特征;(4)通过综合分析论证，提出了坝肩槽高边坡的加固处理方案并进行了作用效果研究;(5)首次采用隐含锚杆有限元子结构形式，系统研究锚杆对边坡岩体的加固作用以及锚杆在随加固区变形过程中存在的反向“锁固力”对岩体变形的抑制作用。更多还原

【Abstract】 Jinping hydropower station is located on Yalong River in Sichuan province with installed capacity 3300 MW. The maximum height of the concrete parabolic double-curvature arch dam is 305.2 meters and it is the highest of the plans in the world. The study of initial stress field is of far-reach significance to the stability of both dam and the underground houses, at the same time, the stability of 300 meters high slope caused by the excavation of the foundation need further research.In combination with the geological data and the measured stress data of Jinping, using three-dimension (3-D) nonlinear finite element method (FEM), initial stress field, the stability of abutment high slopes and the reinforcement measurements of the project are systematically studied.First of all, integrated with the all data what was mentioned, built the 3D-model which can factually image the geological structure of Jinping, the regression estimation and the simulation technique are searched by regression step by step, and one of the two regression precepts which gains by contrast is to provide reasonable initial stress field for the following, the stability analysis of excavation of the high slop and surrounding rock of underground houses.As the initial stress field is determined, the excavation process of abutment is simulated with 3D-FEM, the load-off effect of rock slop and the distribution of stress, distance and the safe coefficient are studied, and then the conceivable failure parts and develop degree of rock are opened out. Based on these, corresponding reinforcement measurements are put forward and their reasonability and reliability are demonstrated.The features of this paper are: (1) according to the geological conditions of Jinping project, model is established fully considering the main faults, deep cracks and joint fissures that accord with actual conditions. (2) In the calculation of initial stress field, the maiden attempt that shear distance is introduced to adjust the direction of principal stress is entered for the simulation of tectonism, and the regression estimate is selected step by step, and then each character of two regression precepts is appraised by synthesis after the weight of the self-weight stress field in the initial geological stress field is discussed. (3) when the distribution of stress field, displacement field and failure information during each excavation process are studied, the nonlinear elastoplastic model named Drucker-Prager and the direct failure model in rock masses are considered in 3D-FME. (4) Through comprehensive analysis and demonstration, reinforcement measurements are put forward for the high slop and their working effectiveness is studied. (5) The sub-structure concerning implicit bolts is firstly used to research the bolts’ strengthening function and their restrain for deformation.更多还原