Stability Analysis Of Goaf In The Agricultural Section Of Yangla Copper Mine

The Linong mine is one of the main mining areas of the Yangla copper mine.The mining methods include the chassis funnel empty filling method,the room method,the comprehensive method and the near surface caving method.One of the main mining methods for the chassis funnel empty field filling method.The current mine has been mined for many years and formed a large number of mined areas.Due to the original design of tailings filled with goaf program application failure.And the new filling program has not been effectively implemented,resulting in a large number of mined areas exposed.There are also overlapping phenomena in the upper and lower layers.So far there have been some landslides in the surface of the mine.Part of the goaf has a sign of collapse,the top of the filling is broken or destroyed,the mine safety production had a serious impact.So it is urgent to study and control the stability of existing mine goaf in Linong mine.By examining a large number of literatures on the classification of factors affecting the stability of goaf,the three factors influencing the stability of mine goaf are put forward.And on this basis,further subdivided into twelve sub-categories,AHP analytic hierarchy method commonly used at home and abroad to obtain the importance of the importance of sorting.The results show that the main influencing factors of the stability of the mine goaf are the geological structure,the pillar size arrangement,the hydrological condition,the empty area and the rock quality index.Selecting the ore body roof,ore layer and ore body floor rock body as the research object,respectively,and combined with the actual situation,do the physical and mechanical tests of density,elastic modulus.Poisson's ratio,uniaxial compressive strength,tensile strength,cohesion and internal friction angle of the three main rock.Finally,the rock mechanics parameters of the standard type determined by the laboratory are transformed into the rock mechanics parameters by using the Hoek-Brown strength criterion.First of all,through the detailed field investigation of Linong ore section,including the mining engineering geological,hydrogeological and other mining technical conditions,the distribution of mine goaf and goaf deformation and damage status etc.;Then through field sampling and laboratory physical mechanical test,and the physical and mechanical indexes of the three kinds of main ore bodies of Linong ore section were obtained through analysis;Finally,the research contents are as follows:1?The calculated results show that the sum of the height of the caving zone plus the fissure zone of mine goaf is 90.32-113.73m;2?The calculation results of the allowable limit span of mine goaf are analyzed by the method of Barton“equivalent size”,when the stope span is less than 21.73m,it is stable under the condition of no support,when the the stope span is above 21.73m,the roof is unstable under the condition of no support;It is very likely to cause the goaf roof to fall;The analysis of the self-stabilization capability of the engineering rock mass shows that the marble roof is a strong and strong rock mass.The Rock quality grades are medium,and the Grade is ?.When the stope span is less than 20m,it can be stable for several days to a month.3?In the stability analysis of the isolation layer of the double-layer ore body,the three-dimensional plate-like structure with boundary constraint is used.The stability of the isolation layer is analyzed by the force of the plate structure.The results of the analysis show that when the insulation tops keep stable,the upper and lower ore body of the pillar overlap rate must be greater than 65%;4?The pillar stability analysis takes the area bearing theory and the Bieniawski pillar strength formula.The results show that the safety factor F of the pillars left by the mine is less than its allowable value ks=1.5.Simply rely on the stay of the pillars to support the stope roof is not feasible.The exposed gob should be treated in time;5?Numerical simulation through the establishment of No.8 exploration line profile on both sides of the 100m range,the range of 400m along the tendency of mining model,and the simulation analysis of six step mining based,obtained in different excavation steps after the simulation of information and data.Through the analysis of pillar stability,analysis of lower mining influence of upper mine goaf stability,analysis of mining impact on strata and surface stability,the results show that the study area mine mining activities in the process of goaf hidden safety problems;6?Finally,on the basis of the above analysis and combined with the existing mining goaf situation,proposed the use of cemented filling way of mine goaf has been exposed to comprehensive treatment,design parameters and ratio of cemented filling and puts forward some matters needing attention in goaf treatment process,through the numerical simulation analysis of the effect of cementation filling scheme proposed in this paper the simulation,simulation results show that the cement filling can effectively prevent the occurrence of goaf disaster.