Three Dimensional Distinct Element Simulations For Rockburst Process Of Granite Specimen

Rockburst is an engineering catastrophe caused by artificial excavation and external disturbance in the high stressed ground. With the increasing number of deeply buriedhydraulic tunnel and other underground engineering, rockburst occurs more frequently. It usually companied by ejection and throw of amount of rock, which threatens the safety of workers and postpones the construction schedule.According to the indoor rock mechanic test, the rockbust process is simulated by using three dimensional distinct element methods. Based on the Three Dimensional distinct element code (3DEC), intact rocks are divided into different sizes of small units and those element are connected by the joints between them, appropriate material and construction model are assigned to each joint through the random assignment function of the software, indoor rockburst ejection process of granite is simulated successfully by three dimension distinct method. The results show that the simulation resuls have tallied the experimental results,simulating the failure process of rockburst is feasible by using above method. It overcomes the shortage of finite element method which can’t simulates the discrete deformation behavior of brittle materials and provides another path for studying the rockburst mechanics.Through the simulation of indoor rockburst test, inner strain field, stress field and energy evolution process of rock are studied in the process of rockbust. According to the strain field, the displacement of rock elements will increase through the free face and some rock element will rebound slightly after unloading, shear displacement of the rock element close to the free face is getting larger at the same time. According to the stress field, the rock elements close to the free face are split and sheared in the process of rockburst, it shows that rockburst is caused by both split and shear. According to the energy evolution process, most strain energy accumulates in the rock as the form of the elastic strain energy especially in the elastic stage before unloading, and the accumulated elastic train energy release suddenly, only 0.84 percent of it changed into after unloading kineticenergy of ejection rocks and 99.16 percent of it changed into energy consumption. The dissipated energy of rock mass is used to conceive,expand and connect cracks.