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Abstract The time-dependent deformation mechanism of surrounding rock of large-scale underground caverns subjected to blast excavation and complex geostress condition is analyzed and a mechanical simulation method is proposed. Based on the analysis of monitored displacements and rockmass mechanics theory，it is identified that the high geostress mechanism and spatial effect of excavation damaged zone are two main affecting factors for the time-dependent behavior of surrounding rock of underground cavern in complex high geostress environment. With excavation process simulated by the stress release finite element method，time-dependent identification functions of excavation release loads and excavation damaged zones are established. Thus，a partition method for sequential excavation loads release based on the monitored curve of displacement vs. time and a deterioration model for deformation modulus on the basis of partial concept of excavation damaged zones are presented. Illustrated with engineering application to deformation analysis of large-scale underground powerhouse of Xiluodu hydropower plant，it is shown that，by coupling calculation of the excavation release load and spatial damaged zone，the simulation method is rational and effective for time-dependent behavior analysis of surrounding rock of large- scale caverns on the whole excavation process，which is of applicability and practical reference for the interpretation and control of deformation and damage effect of surrounding rock under complex geostress condition subjected to blast excavation，for optimizing the construction and supporting，and effective monitoring feedback analysis.
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Received: 31 March 2012
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2013, Vol. 32 
