Abstract The underground powerhouse cavern groups at Xiluodu hydropower station in Jinsha river has huge scale and complex structure. The discontinuity of rock mass induced by the disturbed belts between bedding and inner bedding is the main geologic problem. The elastoplastic damage theory is used to analyze the stability of surrounding rock;and the excavation sequence and supporting parameters for underground caverns are determined. Based on meticulous construction organization,the extent of damage to surrounding rock is strictly controlled to ensure good forming of caverns outline. Real-time analysis and inversion analysis of monitoring data are conducted;and the dynamic design for supporting workload is needed. In the process of excavation,the displacement and stress have a good change regularity. After excavation,the measured values of displacement and stress is relatively small;and the surrounding rock of underground powerhouse caverns has a good stability. The scale of underground powerhouse caverns at Xiluodu hydropower station tops the list in China. The summary from control measures for rock mass engineering such as design,excavation and support,monitoring data analysis and inversion analysis,can provide some references for the similar projects.
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Received: 19 April 2012
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