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The 21st century is the century of the underground works, along with economic development and the advancement of technology, the scale of a large number of large underground cavern development is moving in the direction of great depth, large span, high sidewall multiple cavern Cross arranged , the formation of large underground caverns. Underground caverns in the construction process not only encounter the complex geological conditions, and faced with a complex construction program, different construction procedures lead to different rock mass stress path, after forming underground cavern surrounding rock stability The different results, which is a complicated mechanical processes. In this paper, I witnessed Xiangjiaba hydropower station underground caverns engineering background continuum theory from the field geological survey, structural design, rock mechanics test, theoretical research, on-site construction factors, numerical simulation and on-site monitoring and more aspects of work, optimization and construction process prior to the construction of the underground caverns rock mechanical behavior of the system and in-depth research, including the following: (1) According to the rock scene of the Xiangjiaba right bank of underground caverns Geological Survey, the results of the test data and measured to stress the use of the stress regression analysis method, applied, for the first time, based on the continuum theory three-dimensional discrete element method inversion of the Right Bank Underground Caverns initial stress field, in the project area rock The initial stress field of the body is the main influencing factors and distribution law, as the basis for engineering calculations and analysis of surveillance; (2) to study the energy dissipation characteristics of the underground caverns during excavation, energy method for the first time introduced to the underground cave Xiangjiaba Optimization of construction scheme of the room in Surrounding Rock calculation and evaluation, combined with the calculated surrounding rock deformation, stress distribution and plastic zone distribution characteristics, comprehensive evaluation of the state of surrounding rock in the excavation under the path of the multi-program, than select the optimal excavation scheme; calculation and analysis and comprehensive evaluation based on the the optimal excavation program selection out of four anchoring program drawn up by the underground caverns optimal anchoring parameters. Results for practical engineering applications; (3) large section underground cavern excavation span, buried deep, complex geological conditions and construction program characteristics, combined with the scene of the actual monitoring data, the use of three-dimensional discrete element method multiple the advancing rock physical characteristics, in the process of complex construction process surrounding rock deformation characteristics of the construction process, the principal stress magnitudes, orientation and inclination variation and the variation of the maximum shear stress with the excavation, and based on the results of the above study, first proposed in the the complex excavation environment, based on the surrounding rock deformation, the size of the principal stress values, orientation, inclination and the maximum shear stress of the change process, to determine the large section underground cavern surrounding rock reasonable supporting opportunity weak interlayer layered rock underground cavern surrounding rock phenomenon; (4) based on the on-site monitoring measurements and numerical calculation, the system of the large underground caverns excavation period surrounding rock deformation and the stress change in the law; , based field engineering geological survey, monitoring data analysis and numerical simulation, the weak interlayer cavity surrounding rock stability of the law; found weak sandwich in different parts of the distribution of a large cavern, the corresponding parts of the bolt through the dissection stress value of regular phenomenon; on the basis of the above research methods, combined with the analysis of the construction factors, longitudinal cracks on the top of the rock anchor beam of underground plant parts of concrete and rock at the junction of the new engineering phenomenon, research fissures causes of the root cause of the presence of a weak interlayer produce cracks, construction factors is another important reason, and further study of the development trend of the fissure. The analysis concluded the actual project uses; (5) based on the 5.12 Wenchuan earthquake waveform, underground powerhouse surrounding rock deformation and anchor stress monitoring data obtained by the on-site monitoring, with discrete element software UDEC underground caverns around the earthquake force different parts of the surrounding rock deformation characteristics of rock, the plastic zone and wave velocity characteristics, a large underground caverns in different parts of the response pattern of surrounding rock in the earthquake. Research work in close connection with practical engineering, the establishment of large-scale underground construction mechanical behavior of surrounding rock method for the purpose of Youyi solve practical engineering problems for the purpose of work after the preliminary design and construction of a number of stages, making research and research results have distinctive engineering features, and dynamic engineering design optimization and construction. Paper using a variety of means, the unique system of underground caverns rock mechanics behavior, preliminary design and construction of large-scale engineering rock mass mechanical behavior of a successful practice.
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