Study On The Law Of Overburden Movement And Deformation Of Stopr Under Fully Mechanized Caving Mining Conditions In Huaning Mining Area

China's use of coal is still at a high level of demand.At present,there is a macroscopic study on the development law of coal mining,but the deformation and migration of overlying strata during coal mining is affected by geological conditions and mining conditions.So there is a certain deviation in predicting the deformation and damage value of the overburden in the stope.Therefore,study of the factors affecting the deformation of the geological body in mining site in-depth and the relationship between the multi-factor and the degree of overburden damage have important theoretical and practical significance in controlling surface subsidence and ensuring mining safely.The research object is the mining area of Huaning Company in Shanxi.Due to the existence of geological structure during the mining process,the length of the working face has grown from small to large.The mine is located in the mountainous area,and the surface undulations are different.There are also differences in the thickness of coal seam.In the nearby mines and old goafs,there may exist water accumulation in empty areas.Therefore,determining the development height of the water flowing fractured zone,ensuring that the mine does not communicate with the surface Quaternary diving and the accumulation of water in the old goafs are of great significance for the safe production of the mine.In this paper,theoretical analysis,statistical analysis,numerical simulation analysis and actual measurement methods are used to study the dynamic deformation of overlying strata in the stope under the influence of different factors.The main research results are as follows:(1)The mechanical analysis of the overlying strata movement law in the goaf is carried out,and the failure mode of the overburden in the goaf with the continuous advancement of the mining face is summarized.Collecting the actual working surface parameters of coal mining face and the development height of water guiding fracture zone under mine mining conditions of 56mines,and preliminary analysis of the influence of various influencing factors on the development height of the water flowing fractured zone.And on the basis of reading the literature,summarize the various influencing factors.(2)According to the mining situation,drillings are arranged in the study area,the engineering and hydrogeological conditions of the mine are clarified,and the rock mechanics parameters are sampled to determine the physical and mechanical properties of the coal seam roof.The measured heights of the water flowing fractured zone under each drilling were measured by means of logging,downhole TV,and ultrasonic imaging.(3)Under the background of geological conditions in Huaning mining area,FLAC~3DD software was used to simulate the coal mining model under the mining conditions of mining face.The variables in the numerical simulation process are working face length,coal seam thickness and coal seam dip.According to the simulation results of 16 mining models combined with three factors,the changes of stress,displacement and plastic zone of the roof after full mining are studied,and the influence degree of each factor is sorted.(4)According to the numerical simulation results,determining the development height of the water flowing fractured zone,determining the influence of underground mining on the surface,and finding out the relationship between the maximum displacement of the roof and the maximum subsidence of the surface and the mining conditions of the coal mining face,and determining the displacement situation and the location of the maximum sinking point of the surface.(5)Through the multiple linear regression analysis,the calculation formula of the water flowing fractured zone height of Huaning mining area is established.The calculation formula is used to predict the height of the water flowing fractured zone of 22107 working face,and the prediction results and measured results will be compared.Based on the measured data of several sets of mines,the accuracy and comparative analysis of the calculation formula and empirical formula of the water flowing fractured zone are carried out.