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Abstract The transient release of excavation load is accompanied by the development of cracks，the outburst of detonation gases and the formation of new free surface during the rock fragmentation by blasting. For the case of full face excavation of deep tunnel，divisional excavation loads corresponding to milli-second delay blasting are decided first；and a mathematical description of the load boundary condition during the release of excavation loads is presented through analyzing the mode and duration of transient release of excavation loads. Considering the complex stress stale and change of continuity state of rock mass around blast hole caused by rock fragmentation by blasting，an equivalent numerical method is proposed to simulate the coupling of blasting load and excavation load for multi-hole blasting in accordance with the spatial distribution characteristics of blast-induced damage zone and the equivalent elastic boundary. Comparison between simulation results and monitoring data indicates that the proposed equivalent simulation method is applicable to predicting the dynamic response of surrounding rock during the blasting excavation of deep tunnel.
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Received: 14 February 2011
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2011, Vol. 30 
