Research On The Stability Analysis And Treatment Scheme Of A Large Open Area In An Iron Mine

In recent years,according to the country's launch of the corresponding policy of green and safe mining,the stability of the open space formed by underground mining has been highly concerned by the government.Gobs not only pose safety risks for mining workers,but also pose safety hazards to the lower mining.Due to the complexity of the conditions of the empty area and the occurrence conditions,the stability of the goaf cannot be determined.When the exposed area of the roof in the empty area is too large and the volume is too large,the risk of damage to the empty area is greater when there is no pillar support.This article relies on the analysis and management of the stability of large empty areas as the research theme,combining with the actual large-scale empty areas in the mine,adopts an integrated approach,and conducts on-the-spot investigations and monitoring,theoretical analysis,and numerical simulation of the goaf area,and stabilizes large empty areas.Analyze the sexuality,and based on the analysis results,propose solutions to the empty areas.?1?Through the method of on-site engineering geological survey,using the method of quality evaluation of RMR rock mass,the quality evaluation scale of mine rock mass is grade II.Through indoor testing methods,relevant formulas were used to calculate evolution,and the mine rock mechanics parameters were determined.?2?Mechanical analysis method was used to analyze the damage rule of overlying strata on empty roof,and the"three belts"division of overlying strata in free space was proposed,namely,the fall zone,fissure zone and curved zone.Through theoretical analysis,the mechanical model of the roof in the empty area was constructed.The method of fracture arch theory and limit analysis were used.The results were calculated and analyzed using Matlab software.The fitting formula for the safe thickness of the roof in the empty area was obtained as H=0.67L+0.956.?3?The SURPAC and FLAC^3D hybrid modeling techniques were used to construct a calculation model for the void region.Under the stress condition of self-weight,the stability of the void area was numerically analyzed,and the stress-displacement cloud map of the empty area was obtained.From the analysis of the map,it can be seen that the stress concentration in the goaf is mainly in the rock mass around the void,and the larger the span,the greater the compressive stress and tensile stress in the void.Near No.3,the maximum displacement of the overlying strata in the empty area is 9.96 cm.?4?In the past year's monitoring and analysis of the caving situation of the roof in the empty area,the CZK01 and CZK05 fell to a height of about 0.20m in the area with large span,and cracks appeared in the lower part of the CZK02 roof.Combined with numerical simulation analysis,the instability of rock mass near 3# and in the surrounding area was further obtained.?5?Through the investigation of the stability of large-scale empty areas,the empty space treatment plan was studied.Finally,the empty space treatment method was selected to fill the tailings cement,and the filling body was subjected to L₉?3⁴?orthogonal experimental study to determine the lime sand.Ratio,concentration,curing time.According to the characteristics of the empty areas and the recovery of the deposits,the filling sequence was determined as follows:filling from east to west along the trend,and horizontally filling up from the vertical direction.After the completion of filling,the numerical simulation analysis and on-site monitoring of the stability of the large airspace resulted in a significant reduction in the stress of the surrounding rock in the airspace.