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Abstract Taking a deep-buried tunnel in Gaoligong mountain in Southwest China where the geological action is most complex for example，on the basis of tunnel engineering geological condition analysis，the true triaxial compression tests have been performed on granophyre samples because rockburst most probably occurs. According to the in-situ geostress data，the triaxial stress values and loading or unloading styles of rockburst experiment are determined under different working conditions. The experimental results reveal that both unloading and loading-unloading styles can lead to rockburst，but the rockburst intensity of the latter is higher than that of the former，which indicates that the geostress centralization caused by secondary stress distribution has important influence on the rockburst. The process of rockburst usually has a character of gradual rupture，showing that debris flaked off from the sample surface at first，sometimes accompanying with crack propagation，and the block shooting occurs finally. Most test samples show obviously lagging，which means that rockburst always retards after a period of time when loading or unloading. But the rockburst process only lasts for very short time(about 1 s)，showing obvious instantaneous character. The sound radiation monitoring data show that the granophyre samples have extensive sound radiation under outer loading process，which can be a useful factor for rockbust prediction. All above simulation test results and relevant realizations have important significance for deep-buried tunnel construction in the orogen with complicated geological condition.
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Received: 13 February 2009
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