Study On Effects Of Millisecond Blasting On Stability Of Surroudding Rock And Support

The stability problem of surrounding rock and support under millisecond blasting is a complex problem, and is concerned with many subjects, such as Explosive Mechanics, Rock Mechanics and Damage Mechanics etc. Since its instantaneous nature and complexity of blasting, as well as blasting media and the conditions variability, the blasting load after blasting is very random. At present, the research of single-hole blasting have acquire a great achievements, however, rock excavation is generally adopting multi-hole millisecond blasting the single-hole blasting mechanism are very different. Therefore, it is very necessary to analyze the stability of surrounding rock and support under multi-hole millisecond blasting.With ANSYS / LS-DYNA software, based on the engineering design principles of the holes parameters and charge, explosion hole diameter, hole depth, charging parameters are got. And single-hole blasting model is established, with contrast to the computing method of traditional blast loading, the feasibility and reasonableness is proved. As well as the influence of charging volume, type of explosives, rock classification and propagation distance on the blasting load is investigated and some quantization law is given.Then, according to blasting design parameters of the Left Bank f5 of Jinping power station, the millisecond blasting numerical simulation model is given. The analysis on wave propagation of blasting in the condition of single-hole, double hole and multi-hole is implemented. And the results indicates that blasting stress wave can influence each other and superposition under the condition of double hole and multi-hole blasting, which is different from single-hole blasting in essence. So a new multi-hole millisecond blasting load is proposed in this paper.At last, using new millisecond blasting load model and ABAQUS finite element software, the stability of surrounding rock and lining of the Left Bank f5 tunnel of Jinping power station under millisecond blasting load is studied.