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Abstract The zonal disintegration phenomena which are different from shallow buried cavern will form with the increasing of the excavated depth of underground engineering. In order to investigate the failure mechanism and formation conditions of the zonal disintegration，taking the Dingji coal mine of Huainan mine area with high geostress as background，the true 3D geomechanical model tests for circular cavern，horseshoe cavern and gate cavern have been carried out by adopting model similar material and numerical controlling true 3D loading model system under different loading condiotions of the parallel loading and vertical loading along cavern axis direction. The model test results show that：(1) The zonal disintegration is going to happen when the direction of maximum principal stress is parallel to the tunnel axis and the value of stress exceeds 1.5 times uniaxial compressive strength of surrounding rock mass. (2) The boundary of zonal disintegration depends on the shape and size of cavern；the larger the size of the cavern is，the larger the zonal disintegration range is. The model test results help to reveal the generating condition and failure laws of zonal disintegration，which lays a solid test foundation for further studying nonlinear deformation characteristics and failure mechanism of deep rock mass.
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Received: 25 December 2012
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2013, Vol. 32 
