It is the key important problems in the world to research on rockburst disaster mechanism and control countermeasure of the deep mining tunnel under high stress conditions. The principal stresses distribution and energy dissipation were analysed according to the cases of the excavated radius, the stress level, and the nonuniform stress field of the tunnel with UDEC technique. The growth curves of the energy dissipation quantity and the energy dissipation ratio were concave with stress level increasing and the non-uniform stress field aggravating. The growth curve of the energy dissipation quantity were also concave, but the energy dissipation ratio with the excavated radius increasing was almost holding constant. The concentrated zones of the principal stress difference were extended and gradually migrated from the outside to the inside in the tunnel surroundings rock with the non-uniformstress field aggravating. When the horizontal stresses are greater than vertical stresses, the concentrating zones of principal stress difference in the roof are usually having serious consequences than these in the both sides of the tunnel.
Since the first record of rockburst at a tin mine in Britain in 1738, rockburst has always been a big puzzle in mining development engineering. Because it occurs suddenly with characters of dynamic failure, rockburst often brings threat to the safety of constructors and equipments, causes destruction of engineering structures and affects the project progress, until nowit is still one of the conundrums in underground engineering on a worldwide basis. (Shabarov 2001, Singh 1988). Rockburst is often encountered during excavation of deep-buried underground engineering under high stress conditions. It is considered as a dynamic instability phenomenon caused by the sudden release of elastic strain energy stored in the surrounding rockmass as a result of the excavation unloading induced stress dissipation in the stress redistribution process of the tunnel wall.
