Rock Burst Mechanism In High In-situ Stress And Application In Underground Engineering

Rock-burst is the geological disaster that occurs in hard rock of large underground engineering. Many scientists have been paying great attention to the problem. With the development of research work in the field, scientists have concluded some useful results, but up to now there is no unified criterion to predict it. There still have difference between rock-burst theoretical research and practical engineering application. Engineers normally make decisions based on their experiences to avoid the disaster of rock-burst. So it is necessary to further discuss the mechanism of rock burst and measures to prevent rock burst.In this paper, rock burst mechanism in high geo-stress zone were studied by laboratory test and a criterion of rock burst through energy analysis was proposed. Then, damage elastic-brittle constitutive model for granite is obtained and programmed in code ABAQUS, From numerical results, regional, grade and the prevention measures of rock burst in Galongla tunnel is obtained.First of all, unloading confining pressure laboratory tests of granite was conducted, the deformation and failure process of rock were studied. The behavior of energy dissipation and energy release during this process was also discussed, and rock burst mechanism were also discussed based on energy principle. Then, damage elasto-brittle constitutive model was developed. The concept of rock burst damage energy index and the rock burst criterion were developed according to the energy. With the developed elastic-brittle constitutive model and rock burst criterion of granite, rock burst prediction of Galongla tunnel was studied by numerical simulation considering different exacavarion method and speed. Furhermore, rock burst criterion considering multiple facors were developed on the baisis of BP network theory according to the experiences of past underground engineerings. Finally, the preventing measures of rock burst were studied and reasonable excavation method and speed were proposed for tunnel construction on site.