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Abstract During the tunnel boring machine(TBM) excavation，two types of slabbing failures in these deep-buried marble tunnels are discussed. One is violent slabbing rock burst and the other is non-voilent slabbing and spalling. In order to study the slabbing failure，true triaxial experiments for modeling the rock burst at different in-situ stresses are carried out. Results show that all of the specimens appeared slabbing. The phenomena observed in the experiments are very similar to that at the tunnel site in Jinping II hydropower station. The experiment explains basically the tunnel face and tunnel side rock failure phenomena at present，and also displays the main failure types during the TBM excavation in the future. The influence of the slabbing failure at tunnel face and tunnel side on TBM excavation is analyzed and discussed.
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Received: 25 February 2010
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