Study On Surface Subsidence Rule Caused By Mining In The Complex And High Stress Environment

ABSTRACT:Because of the variety cause of metal deposits, complex geological structure of the rock mass, rock mechanical properties of various and different boundary conditions, the surface deformation theory of the coal mine can not be applied directly to metal mine. Therefore, in the complex and high stress environment of metal mine, the research of surface subsidence caused by mining will provide technical support on recovery ore resources safety and efficiently, and has important guiding significance for production safety.It analyzes the horizontal deformation rule and subsidence rule of monitoring sites based on the monitoring data of Long Qiao mine, and establishes the digital subsidence model, and maps the surface subsidence contours and subsidence sections. With the help of the mining space-time order, it mines surface subsidence evolutionary rule of spatial distribution comprehensively. The results show that the surface deformation is association with roof caving rules, and the spatial distribution of surface subsidence areas are obviously, and cumulative subsidence centers are exist in4#exploration line and1#exploration line, which extend to the surrounding and became smaller. The area of accumulated subsidence obvious is1-3#exploration line, in which the correspondence between underground mining and surface subsidence spatial evolution is obvious, it is recommended to focus on surface deformation monitoring area. Based on drilling monitoring data and geological tectonic characteristics and analysis of rock mass quality, it explained caving mechanism reason of goaf roof strata, put forward that the caving state of goaf roof strata is proportional to the corresponding goaf span exposure rate.According to the key mining environmental factors and the characteristics of underground mining process of metal mine. The grey correlation analysis method is used for the correlation analysis of surface subsidence due to the key mining environmental factors, and it makes influence degree of factors quantified for the first time, which makes up the inadequacy of qualitative analysis of the past. The results show that cohesion C and friction angle? is the determining factor affecting surface subsidence, tilt a and stope dimensions A are the main factors affecting surface subsidence, the elastic modulus E and mining depth H are some effect on surface subsidence, but the relative degree of association are small. At the same time, the sensitivity function of the influencing factors is established, and the effect degree of various factors on the surface subsidence is deeply analyzed.Based on PCA and BP, combined forecasting method is put forward first and applied in rock movement angle prediction of metal mine. The method simplifies the complex influence factors and raw input data, retaining the main component information, improving the whole stability and accuracy of BP prediction. With the prediction result of rock up and footwall movement angle, introduced3D modeling technology, it map out the range of surface movement of Long Qiao mine in the eastern area for the first time, which makes up the deficiency of ambiguity of the existing surface movement range. The results show that the overall range of ground movement is at the top and greater than goaf range, and the main shaft and ancillary buildings, water, and residential are beyond the surface movement, which is no impact on mine safety production, and towers and ancillary facilities are on the boundary range of surface movement, which exist some security risks, and need to strengthen preventive measures.Three-dimensional numerical calculation models based on FLAC3D software are established, and underground mining activities of Long Qiao mine are simulated, and a comparative analysis of the spatial evolution distribution rules of surface subsidence is made on the background of horizontal tectonic stress and gravity stress. The verification results of the surface measured data and the numerical simulation calculation results show that the simulation of tectonic stress is more consistent with the measured data of the surface deformation. Taking the typical cross section of1#and4#exploration lines as the research objects, the movement and destruction characteristics of goaf roof strata and the stress response characteristics of around rock under the condition of different span are simulated and analyzed, which gets inner relationship of the goaf span and the movement damage and cavity of goaf roof strata, and reveals the evolution process of the vertical deformation of overlying rock strata to goaf span.According to the lack of study on underground mining subsidence prediction of tectonic stress mine, the generalized ground stress concept of tectonic stress mine is defined, and by introducing probability integral principle and the influence of ground stress, and the improved random medium theory is applied to surface deformation prediction in the eastern of Longqiao mine. The results of monitoring points show that the calculation result of the surface deformation under weight stress are more than calculation results under the improved random medium, and the existence of tectonic stress can slow the impact of surface subsidence.Based on the unascertained theory of clustering optimization, it verified the calculation accuracy of the improved random medium theory. The results show that the prediction results of the improved random medium is closer to expectations, and higher prediction accuracy, and more instructive on mine safety production.According to the function defects of mining subsidence management information system applying in metal mine, and taking the surface monitoring data of Long Qiao mine as basis, and the MapX5.0control of MapInfo and VB6.0language tools used, it designed and developed Long Qiao mining subsidence management information system based on GIS, which couple the mining subsidence professional models to GIS platform in it for the first time. By means of analysis, research, development and run, the system realizes the drawing function of deformation curve of surface movement and subsidence contours and profiles automatically, and the forecast and early warning function of surface subsidence, and the3D visualization function of subsidence, which provides a very efficient method for the safety production of Long Qiao mine.