Abstract The failure patterns and deformation characteristics of surrounding rock masses in underground powerhouse caverns with different ratios of rock strength to in-situ stress(RSS) were analyzed and summarized,and the relationships between the RSS and the bearing capacity,the failure patterns and the deformation characteristics of surrounding rock masses were expounded. Based on the large amount of the statistical design data concerning the layout of caverns in hydropower stations,an innovative design method for the layout of underground caverns was proposes. The specific quantitative indicators and the related calculation formulas were presented. This method emphasized the important influence of RSS on the layout of caverns and based on the past experiences,the numerical analysis results and the recent findings in this field. The proposed method also took account into the interactions of adjacent caverns,the characteristics of in-situ stress in canyon region where caverns located,the classification of in-situ stress according to its magnitude and the distribution of weak discontinuities(e.g. joints and faults which are the main factors affecting the stability of underground caverns) etc.. It can be applied to the layout design of underground caverns under various stress levels or complex geological conditions.
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Received: 26 June 2014
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