Optimization Of Stope Structure Parameters In Room-and-pillar Mining Of Slow-thin Ore Bodies In Jinsha, Yunnan

In order to ensure the safety of mine production and the full recovery of mineral resources,the distribution of roof and pillar stress and displacement,the stability of stope and the residual deformation of surface are intensive studied in the process of mine infrastructure construction and production and operation.On the basis of field surface subsidence investigations,ground stress activity,joint structures of the rock mass,laboratory tests and surface residual are carried out,by combining the fuzzy synthetical evaluation on the system based on analytic hierarchy process,the thin plate theory,the numerical simulation and the time series In SAR technology to modify the mechanical parameters of ore and rock mass,the stope structure parameters of Jinsha ore block and the surface subsidence deformation accurately,and carry out the optimization of stope structure parameters.The main research contents are as follows:（1）According to the investigation results of surface subsidence,the mining activities in Jinsha ore block caused the residual deformation of the surface.Using the70 scenes of Sentinel-1A data collected from the research area,and using the small baseline subset In SAR technology（SBAS-In SAR）for monitoring mining area.Meanwhile,the cumulative subsidence deformation and time series subsidence of the study area are obtained by arranging the profile lines and surface feature points.Experiments show that the time series In SAR monitoring can obtain the subsidence rate change trend of the surface subsidence area,and then provide the basis for the evaluation of the stability of goaf and surface buildings.（2）Combined with the field engineering geological survey and the statistical analysis of the occurrence information of the rock mass discontinuities,the information generalization diagram and probability distribution diagram of the dominant discontinuities in Jinsha ore block are established,and the mechanical properties of the rock mass and the distribution of the discontinuities in the study area are understood.（3）The fuzziness mathematics theory evaluates the characteristics parameters of rock mass more effectively and objectively.This paper introduces the number of dominant joint sets(₉)),joint spacing（d）,the integrity coefficient of rock mass(),the roughness coefficient()and the fluctuation coefficient()to describe the structural characteristics of rock mass.The multifactor fuzzy-synthetical evaluation is applied to the system of geological strength index,meanwhile,analytic hierarchy process is adopted in determining the membership weight.As a result,the model of fuzzy-synthetical evaluation on the system of geological strength index is established.This method can combine the field investigation results,experts’engineering experience and result inspection organically,and has strong pertinence and high accuracy.The method of fuzzy-synthetical evaluation on the system of geological strength index has provided a new approach to quantizing other parameters of rock mass.（4）Firstly,the stability of large-span stope roof is analyzed by using the thin plate theory analysis method.Then,12 kinds of stope excavation models are constructed by using the large-scale 3D modeling software Midas-Gts,and imported into the FLAC^3D numerical simulation software to analyze and compare the stress,strain and displacement of goaf roof after ore body excavation,so as to determine the optimal stope structure parameters.