Prevention method for rock bursts based on control of dynamic effects caused by transient release of in situ stresses

For excavation of a deeply-buried circle tunnel by the method of full-face blasting, the process of transient release of in situ stresses on excavation faces is briefly introduced. The stress and strain energy adjustments in the surrounding rock masses induced by the transient process are analyzed, and the main factors affecting the dynamic effects are also discussed. The results show that the dynamic effects of the transient release of in situ stresses are positively correlated to the strain energy magnitude of the rock masses to be excavated and the release rate of the strain energy. By controlling the dynamic effects caused by the transient release of in situ stresses, a prevention method for rock bursts during the construction process is proposed. In this prevention method, the direction of in situ stress on the blasting work face is first predicted according to the distribution of blast-induced cracks around a blasthole, and then the blastholes in a round are sequentially detonated in the order of the strain energy density from high to low. By changing the initiation sequence of blasting, the dynamic effects due to the transient release of in situ stresses are significantly reduced. The proposed prevention method can find widespread application in the holing blasts of deep-buried opening excavation in hydropower, mining and transport industries.