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Summary The dynamic disturbance from explosion, earthquakes and stress impact may induce rock mass damage around the deep-buried tunnel. Here we show the dynamic responses triggered by blasting load disturbance. In this paper, the theoretical formulas are firstly derived to evaluate the time-domain dynamic responses based on the wave function expansion method and the inversion of Laplace transform and then a self-developed numerical code, i.e. elasto-plastic cellular automaton (EPCA), a module of CASRock, is subsequently employed to simulate the blasting induced elasto-plastic dynamic responses. It can be found from the analytical solutions that tensile stress concentration at two sidewalls occurs, while compressive counterpart at the roof and floor appears. Moreover, the radial velocity vibrations generate concentration at the two sidewalls, while the circumferential counterparts appear at the roof and floor. The numerical simulations indicate that compression-shear and tensile failure are the major mechanism for the rock mass damage around the rock tunnel. The analytical and numerical results help to understand the velocity vibrations and the major mechanism of rock mass damage and provide theoretical basis for the support of rock tunnel.

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To investigate effect induced by blasting in Jinduicheng molybdenum mine on the Dongchuan river diversion tunnel, the tunnel vibration has been monitored. According to the actual conditions, the corresponding numerical simulation is performed in FLAC 3D , and dynamic response of the lining and surrounding rock of the diversion tunnel caused by blasting load is analyzed. The variation of vibration velocity in the later stage of tunnel under the action of existing blasting scale is predicted, when the vertical distance between blasting source and diversion tunnel is 50 m, the velocity of tunnel vibration reaches the critical value. The blasting scheme of mine production can be modified according to the practical distance between the explosion source and the diversion tunnel.

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