Period Of Middlings Was Ma Iron Mine Goaf Stability Studies Under The Influence Of Blasting Vibration

Along with all sorts of underground mineral resources being mass exploited all over the country, more and more unhandled timely goaf regions are existing, which cause more serious geological disaster and lead to a huge economic losses to enterprises and the whole society. This essay, combining with the issue of " The ground pressure detecting for iron mine and the technical researches for managing goaf regions in Fujian Ma Keng", adopting the current researching status for goaf resign, the blasting vibration monitoring, the analysis for blasting vibration effect and the numerical simulation, and also the ways of fuzzy comprehensive evaluation, to make a deep research for the stability of blasting vibration for the goaf regions which caused from the first stage of technical reforming and deepening in Ma Keng, and to offer certain theoretical statistics to handle steadily the goaf regions in the mining areas. Researches for the details are as follows:(1) Make the status survey for the goaf regions concerned, including shape of the area, the top (base) board exposing proportion, volume, span, occurrence State etc.,. In the meantime, take the damage of surrounding rock and jambs in the goaf regions into investigation, so as to learn the whole condition of the area, and provide the references to the establishment of numerical calculation model and the fuzzy comprehensive evaluation of the risk degree in the goaf regions.(2) Design and implement the blasting vibration monitoring schemes for the goaf region, account and analysis the detected data, and finally get the blasting seismic wave attenuation rules in the current ways of using the medium deep hole blasting vibration methods and ways in the blasting detected area.(3) On the basis of analysis the blasting vibration monitoring in the spots, firstly established the blasting vibration dynamic contrast evaluation system, predicting the dynamic stress contrast inflection point value from the beginning damage of rock, and using the detected status to make the steady analysis for the jambs and baseboard; Secondly, implement the concept of tunnel "resistance", and integrate the comprehensive coefficient methods to evaluate the stability of the tunnels surrounding the goaf region; and account the maximum explosive dose for single stage of the medium deep hole blasting from the region which is15m safe distance from the tunnel.(4) According to the investigation records of the current goaf resign situation, establish a FLAC3D calculation model which is more correspondent with truth and more reasonable. After the numerical simulation calculation for the mine-out resign model in the condition of self weight stress field and blasting vibration load, and the comprehensive and comparative analysis for the stability of the mine-out region from the3aspects such as the stresses, displacement and ductility distribution regularity, to get the stability status for the goaf resign under the influence of self-weight and to get the dynamic response statistics in the effect of blasting vibration load.(5) Summarize and analyze the20factors which impact the risk degree for goaf resign in Ma Keng iron mine, on the basis of which to build up the secondary risk degree fuzzy comprehensive analysis model in the influence of blasting vibration, and take into effect the secondary risk degree fuzzy comprehensive analysis for the23representative mine-out resigns. In accordance with the maximum membership degree principles, so as to determine the risk degree for each goaf resign, the assessment results approximately tally with the investigation records of the region in the real spot. And put forward some related proposals for the solutions to the goaf regions below the funnel collapsed in the middlings section.