Numerical Simulation And Fracture Mechanics Analysis On Cutter Fragmentation Rock Under Dynamic And Static Load

Mechanical rock broken engineering is playing more and more important role in mining, subway construction, tunneling such project fields. At present, in all the engineering practice, the machine almost choose to break rock, due to the complexity mechanism of rock fragmentation, especially the rock breaking mechanism in different complex stress condition would be a long-term task. It is that workers of rock mechanics and crushing engineering must to research. There are large amounts of rock internal cracks, joints and their presence which changed mechanical properties of rock greatly which affects the rock failure process and crushing efficiency.The research work is supported by National Natural Science Foundation (No.50974059) and carried out theory analysis and numerical experiments based on the single static load, the single dynamic load and static and dynamical combination load of rock fragmentation.It established the mechanical model of a single crack under the static and dynamical combination load based on the analysis of rock broken characteristics under the single static and dynamic load. Then it applied the fracture mechanics to analysis the rock mechanical response of a single prefabricated crack under single static load and combination loads which obtained the rock fracture criterion with prefabricated crack under the condition of static and dynamical combination load.The rock fragmentation effect was influenced by the cutter shape, scale, loading ways. It obtained the broken rock characteristics of concentration cutter, cone in a single spherical cutter blade under the single static load. Different lengths of cutters produced different crushing effect, when cutter length equals to the crack length, largest volume and the best broken rock fragmentation effect. For the three different loading ways, the rock fragmentation lesion dimensions under the static load was widely than the impact load, under the static and dynamical combination load was bigger than the single static load or dynamic load.The prefabricated crack rock breaking process were simulated under a single static load, static and dynamical combination load by the FLAC3D.It showed that prefabricated crack compared with complete rock block failure process were extremely similar under the static load. But its critical strength reduced greatly .Prefabricated crack ends easy cause stress concentration, causing crack airfoil extension and formed the splitting failure. Choosing the time to add the dynamic load plays a very important role of the broken -rock volume. The preload static load make the rock produce volume fragmenting then applied impact load and the rock blasting results are the best. Numerical simulation results are basically the same to the results of the former research of rock fragmentation under the single static load and the impact load. And it also proves the reliability of numerical simulation.