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Abstract Because of complex tectonic boundary condition and high stress environment in deep rock mass，surrounding rock has intrinsic characteristics，which will damage caused by stress redistribution in excavation of deep-buried tunnel. The traditional rock mechanics has been always focused on the stress state and failure criteria under the hypothesis of rock homogeneous，the total rock mass failure process is not considered yet. With the development of meso-damage rock mechanics，the method of damage mechanics has been proved to be better than the traditional theories. But relevant researches are not available at present. Based on the numerical test on damage property of tunnel surrounding rock in an excavation section K22+029 by using the software RFPA2D(two-dimensional rock failure process analysis system)，which was developed according to meso-damage mechanics of rock mass，the total failure process of surrounding rock in deep-buried tunnel is simulated，the failure mode，acoustic emission(AE) map and shear strength map in the failure process are shown quantitively；and the damage index is also achieved by velocity test with EMS–2 engineering multi-poly seismic system. It is found that the hard rock mass in deep-buried tunnel is fractured firstly at the roof，then at the spandrel；and finally the fracture extends to the deep layer. Damaged surrounding rock shows obvious characteristics of nonlinearity and localization. The possible failure mode and the relationship between AE amounts and damage variable of surrounding rock in deep-buried tunnel can be obtained from the analysis by using meso-damage mechanics. It is shown from in-situ test results by engineering multi-poly seismic system that the attenuation of longitudinal wave accords with the change of damage variable in tunnel surrounding rock. The conclusions have great application values for tunnel construction and supports. What¢s more，these are also beneficial tries for the study on failure mechanism of deep rock mass.
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Received: 18 April 2007
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