Empty Area Under Complicated Conditions Induced Effect Of Strata Movement And Roof Caving

Large area caving goaf roof induce impact ground pressure is one of the major forms ofdisasters in mines, In order to ensure the mine safety, efficient and orderly mining, To ensuremaximum recycling resources, Strengthen the cavity induced by overlying strata movementand roof caving regularity study is of great significance. In this paper, By theoretical researchand field measurement and computer simulation research method of combining,Comprehensive system of empty areas under complex conditions induced rock movement androof caving regularity analysis，Reveals the effects of mining iron ore mining generatedLongQiao, The main research contents and results are as follows:In this paper, based on FLAC3Dmodel SURPAC,The simulation of Longqiao iron roofof pillarless sublevel caving mining technology induced caving space movement and rockevolution, The results can be summarized as ore mining destroys the balance of the originalrock stress, Sparked an empty area surrounding rock moves and stress transfer, Subsidencecaused by roof, roof muster, between two rock collapse phenomenon, With the increase ofmining depth and span of the roof of an empty area of maximum principal stress, The stressconcentration area is also expanding, Empty area of the maximum principal stress roof willalso be turning into a tensile stress stress, To some extent, the stress plate has also beenreleased, With the rock away from the empty area, Stress will also be restored to its originalrock stress state.According to the energy balance point of view and the theory of gas dynamics,Establishment of a mechanical model of the impact of large-scale disasters blast rock roofcollapse accompanied, And Long Qiao iron ore shock waves turbulence model are calculated,Calculated the maximum of rock caving cause air flow speed, the impact of block cavingblasts the maximum speed and ensure the underground work personnel a safe distance fromthe minimum distance of placement of rock.Based on the condition of the ground penetrating radar (GPR) principle and method ofcavity roof cladding thickness detection, The detecting images can clearly display ore-bearingrock cover thickness has reached the two layer thickness, Satisfies the requirement of safeproduction regulations of the state, to ensure the safety of underground work. Meanwhilephotography by drilling a large empty area of monitoring data indicate the presence of roofrock caving certain regularity, Its evolution over time of caving process can be summarized as:The relatively stable stage, the initial caving stage, continued falling stage.Combined with the grey model, least square support vector machine method of artificial intelligence and other advantages, proposes the prediction method of intelligen residual typebased on G-LSSVM. The SVM model, GM (1,1) model and the residual-type G-LSSVMmodel were used to overlay LongQiao iron ballast stone caving height and thickness of theforecast, The residual type G-LSSVM forecasting accuracy is better than a single SVM andthe GM (1,1), The model can avoid the blindness and randomness of a single artificialintelligence method to predict, Can be applied to the engineering field. Accurate and timelyforecast to caving height and thickness of ballast stone is of great significance for therecovery of high security, underground iron resources.