Abstract:

Rockburst is one of the main geological hazards during tunnel construction in high geostress zone. The prediction of possibility and classification of rockburst is one of global problems of tunneling engineering. Based on efficacy coefficient method, a new model for predicting the classification of rockburst is established. Considering the key influential factors of rockburst comprehensively, four factors including ?θ /?c, ?c/?t, Wet and Is are selected as evaluation indices. The model is tested by a series of rock projects at home and abroad. The obtained results are consistent with practical classification of rockburst and the results of set pair analysis method and extensional method; so it is shown that the efficacy coefficient method used to classify the rockburst intensity is reasonable and effective. Then, the model is applied to Cangling tunnel. The results are in good agreement with practical situation of rockburst. It is proved that the efficacy coefficient method used to classify rockburst intensity is exact and reliable. The efficacy coefficient method is simple and has very strong operability, which possesses a good prospect of engineering application.

Key words: tunneling engineering, rockburst, efficacy coefficient method, classification prediction, influential factors