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为实现数值仿真计算结果能准确反映大型洞室围岩实际力学行为,结合锦屏二级水电站地下厂房枢纽洞室群稳定性分析,在阐述大型地下洞室群数值仿真计算要点基础上,首先重点从岩体本构模型识别和力学参数识别2个方面详细介绍如何实现数值仿真计算的正确化。采用考虑空间分布协调的多元监测信息的6次岩体力学参数跟踪识别,获得锦屏二级地下厂房岩体的等效力学参数,从而通过参数反分析的方法在一定程度上证明岩体等效力学参数具有相对稳定性和可识别性。同时,结合数值模拟展现出的围岩应力、变形、塑性区等方面计算结果与工程岩体的具体地质条件和洞室群结构特点,论述锦屏二级水电站地下厂房上游高边墙变形较大、下游侧拱围岩与喷混凝土破坏、母线洞环状开裂、交叉洞口局部塌落等洞室围岩的变形与破坏机制。最后,结合锦屏二级地下厂房枢纽洞室群稳定性分析与实践的研究认识,对大型地下洞室修建中诸如结构面密集的高边墙支护问题、围岩应力集中区支护问题、工程区地下水对围岩稳定性影响等问题进行论述,并探讨如何通过数值仿真计算、现场监测与经验丰富的专业人员的有机结合来实现大型地下洞室群稳定性设计的科学化。
In order to realize the numerical simulation results accurately reflect the actual mechanical behavior of surrounding rock in large caverns, based on the stability analysis of the cavern group of underground powerhouse of Jinping Hydropower Station, based on the numerical simulation calculation of large underground caverns, How to realize the correctness of numerical simulation calculation is introduced in detail from two aspects of identification of rock mass constitutive model and identification of mechanical parameters. The six parameters of rock mass mechanics parameters tracking and identification with multi-monitoring information considering the spatial distribution coordination are used to obtain the equivalent mechanical parameters of the rock mass of the second underground powerhouse in Jinping. The parametric back analysis is used to prove that the rock mass equivalent The learning parameters are relatively stable and identifiable. At the same time, combined with the numerical simulation of the surrounding rock stress, deformation, plastic zone and other aspects of the calculation results and engineering rock mass geological conditions and cavern group structure characteristics, discusses the Jinping second stage hydropower station upstream of the high-wall deformation of the underground plant larger , Deformation and failure mechanism of the surrounding rock in the surrounding rock of the downstream side arch and concrete, destruction of the shotcrete, ring-shaped cracking of the bus tunnel and partial collapse of cross-hole. Finally, combined with the research and analysis of the stability analysis and practice of the cavern group in the underground powerhouse of Jinping, the problems such as the support of the high side wall with dense structure and the support of stress concentration area in the surrounding rock are discussed, The influence of groundwater in the project area on the stability of the surrounding rock is discussed and how to realize the scientific design of the stability of large-scale underground caverns through the numerical simulation calculation, the combination of on-site monitoring and experienced professionals is discussed.