Numerical Simulation Research on the Dust Dynamic Diffusion of Cutting Deep Hole Blasting
GUO Yao1, MENG Haili2
1. China University of Mining and Technology(Beijing),Beijing 100083,China; 2. Railway Engineering Research Institute of China Academy of Railway Sciences Corporation Limited,Beijing 100081,China
Abstract:Research purposes: With the frequent occurrence of catenary operation accidents caused by dust pollution in electrified railway network, higher requirements are put forward for cutting blasting in close proximity to existing railways. Based on this, starting with the qualitative analysis of the diffusion law of blasting dust, this paper analyzes the dynamic diffusion characteristics of cutting deep hole blasting dust and the diffusion distribution range of dust with different particle sizes by using ANSYS Fluent numerical software, and puts forward the blasting construction scheme at different distances close to the existing line. Research conclusions: (1) The movement process of blasting dust can be roughly divided into three stages: the enlightenment stage, the stretch stage and the expansion stage. The duration is controlled within 1.5 s, 5 s and over 60 s respectively. (2) The dust above the blasting area is mainly concentrated around the blasting area, while the dust in front of the free face spreads along the direction of air flow, and the maximum vertical height that dust particles can reach is about 14 m. (3) When 10 m ~15 m away from the position of the blasting free face along the direction of air flow, dust particles with particle size > 100 μm are basically deposited by gravity; at 15 m ~20 m, dust particles with particle size between 40 μm and 100 μm also settle rapidly; beyond 25 m, dust particles with particle size < 20 μm are dominant. (4) When the distance between the edge of the blasting area and the catenary is less than 20 m, the blasting throwing direction should be parallel to the existing railway direction, and the direction of air flow at the initiation should also be parallel to the existing cable direction. At the same time, if water mist dust removal measures are adopted, the time of water mist generation should not be later than the initiation time of the main blasting area by 1.5 s, and the height of water mist should be controlled at 14 m. (5) The research results can be popularized and applied in the field of close to electrified railway or strict control requirements for blasting dust.
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