Study On The Method Of Subsidence Monitoring In Mining Areas Based On UAV Photogrammetry Technology

Surface subsidence caused by underground coal mining is the main factor affecting the ecosystem,and obtaining the accurate shape of mining subsidence basin is the basic work of mining subsidence prediction.The traditional mining subsidence deformation monitoring can only obtain the deformation of a few monitoring points on the main section of the subsidence basin,and the deformation of the whole basin can be retrieved by the deformation of monitoring points,which has great limitations.Aiming at the subsidence caused by mining area,combining the mining progress and geological data of Inner Mongolia Autonomous Region wangjiata coal mine 2S201 working suface,this paper designs a scientific aerial photography flight plan.Unmanned aerial vehicle is used to monitor the mining area for multiple periods to obtain image data of the surveyed area,and the image data is processed by UASMaster software to obtain point cloud.Because there are a large number of non-ground points in the initial point cloud,the subsidence data obtained by superposition of these points is inaccurate,which affects the analysis of subsidence area law.Therefore,the gradual triangulation encryption algorithm is used to carry out experiments on the point cloud data,and the outlier noise points of the point cloud are removed by combining manual intervention,so as to obtain the ground point data of the four-phase experimental area.The acquired ground points are extracted at 10 m intervals,and the superposition of the ground points is realized by combining MATLAB software to obtain the three-phase subsidence data.Taking the subsidence data of the third period as an example,different interpolation algorithms are used to construct subsidence basins.Quantitative and qualitative analysis shows that,according to the characteristics of unmanned aerial vehicle monitoring subsidence data,the local polynomial interpolation algorithm is used to construct subsidence basins in mining areas with higher accuracy and better fitting effect.Finally,the probability integration method is adopted to predict the subsidence basin.Based on the measured data of total station,the accuracy of the predicted basin and aerial survey basin is quantitatively analyzed.The experimental results show that using unmanned aerial vehicle to monitor the subsidence of mining area,the measured subsidence value at the same check point is basically consistent with the subsidence value of subsidence basin obtained by aerial survey,and the accuracy of aerial survey subsidence basin is better than that predicted by probability integral method.The subsidence curves on the main section of the aerial survey basin and the prediction basin are extracted.Through comparative analysis,the subsidence trend of the aerial survey basin is consistent with that of the prediction basin in the experimental area,and the aerial survey basin retains more subsidence details.