Study on Rockburst Tendency of Deep Underground Engineering based on Multi-Factor Influence

Rockburst disaster seriously threatens the construction schedule of underground tunnel engineering and the safety of construction workers. Rockburst prediction has become one of the critical methods for evaluation of surrounding rock stability and safe construction of deep underground engineering. To further understand the occurrence mechanism of rockburst disaster and predict rockburst in underground engineering more accurately, firstly, the typical rockburst tendency criterion and the critical factors affecting the rockburst development process are systematically summarized and analyzed, and the main control factors reflecting the whole process of rockburst development are screened and analyzed: mechanics, brittleness, integrity, and energy storage factor. Secondly, according to the comprehensive consideration of the main control factors, based on the energy conversion and overall failure mechanism in the process of rock failure, a new multi-parameter rockburst tendency criterion is proposed by comprehensively considering the stress states of rock unit under different stress paths. Finally, the rockburst criterion proposed in this paper is applied to typical engineering cases to verify its rationality and accuracy. Based on a rockburst section in the Sangzhuling tunnel, the possible location of rockburst is simulated based on the 3D discrete element numerical simulation platform, and the rockburst criterion proposed in this paper is further verified by actual engineering. The results show that: the rockburst criterion considering the mechanical factor(σθ/σc), brittleness factor(σc/σt), integrity factor (Kv) and energy storage factor (Ue/U0) can comprehensively and truly reflect the rockburst development process; based on the rockburst tendency criterion proposed in this paper, the occurrence of rockburst in typical engineering cases is calculated and verified, and the predicted results are in good agreement with the actual situation; the numerical simulation of the typical rockburst section prediction in the Sangzhuling tunnel shows that the distribution characteristics of rockburst tendency based on the criterion in this paper are consistent with the on-site rockburst occurrence, and there is a strong rockburst tendency on the right of the tunnel vault, which further verifies the effectiveness and engineering applicability of the criterion in the rockburst tendency prediction. The results of the research can provide some reference for predicting the tendency of rockburst in deep underground engineering.