Numerical Simulation Study on the Delay of Rockburst Based on Rock Mass Stress Release Rate

Rockburst is a phenomenon of geological hazard due to excavation in brittle rockmass of high in-situ stress which endanger to the engineers and construction equipments with unexpectedly damaged. At present, researchers and engineers mainly concentrate to the requirement of rockburst and whether to arise. Although the delay characteristic of rockburst (DCR) has been realized and recorded, but the knowledge of the mechanism of this feature is insufficient. In the paper, the delay characteristic was researched from the stress release rate (SRR) of the excavation rock mass using the numerical simulation software. Firstly, using the core replacement technique, the relation of the SRR and core modulus reduction (CMR) was determined. Secondly, the mechanism of the DCR was analyzed from the elastic strain energy distribution and the plastic strain energy distribution in the different SRR. Finally, the plastic field shape and range under different SRR was contrasted and analyzed. Conclusions can be drawn as follows: with the increase of CMR value, the SRR shows increase trend in the form of exponent. In the process of excavation, the rockmass elastically deform under the low SRR value. When the SRR value equals certain degree, the portion of rockmass will be plastic field and behind the plastic region there will be arise a elastic strain energy centralized phenomenon. Under the different the SRR value, the field style change to the tension-shear field from the shear field in the rock mass and the rockburst rank obviously different.