(1. China Three Gorges Corporation，Beijing 100038，China；2. Engineering Research Center of Rock-soil Drilling and Excavation and Protection，Ministry of Education，China University of Geosciences，Wuhan，Hubei 430074，China；3. Zhejiang HydroChina-ITASCA R and D Center，Hangzhou，Zhejiang 310014，China；4. HydroChina Huadong Engineering Corporation，Hangzhou，Zhejiang 310041，China)
Abstract：The proposed hydropower station which is located on lower reaches of Jinsha River is characterized by the large scale and complex arrangement. The height of cylindrical throttled surge chamber is about 100 m，and the diameter reaches 50 m. The stability and supporting measures of chamber arch are the noteworthy factors needed to be considered. In order to analyze potential stress-type failure，deformation and collapse caused by structure planes of tailrace surge chamber arch crowns under complex geological conditions，engineering geological analysis and three-dimensional numerical simulation(3DEC) are adopted to study the stress concentration arrange，stress concentration degree and risk of high stress failure，and the effects of interlayer fault zones on stability of surrounding rock are demonstrated. The results show that the overall stability of cavern satisfies the engineering requirements，and the relatively stress concentration degree(30–44 MPa) of arch crown doesn?t cause prominent issue of high stress failure. However，bedding fault zones reduce the stability of surrounding rock distinctly，thus large sliding deformation occurred along the bedding fault zones and shear yield occurred in NNE direction from surface to 7 m superficial zone. After strengthened reinforcements including system supporting and concrete replace are adopted，sliding deformation of bedding fault zones is reduce obviously，and interlaminar band security reserve is improved.
江 权，冯夏庭，陈国庆，等. 高地应力条件下大型地下洞室群稳定性综合研究[J]. 岩石力学与工程学报，2008，27(增2)：3 769-3 777. (JIANG Quan，FENG Xiating，CHEN Guoqing，et al. Stability study of large underground caverns under high geostress[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(Supp.2)：3 769-3 777. (in Chinese))
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2012, Vol. 31 
