Research On Surface Movement Law Of Strip Coal Pillar In Super-high-water Filling Mining

Mining strip coal pillars is an important technical way to extend the service life of mines in the middle and eastern mining areas of China.The study of the rock and surface movement law of strip coal pillar by filling mining is a key issue in the promotion and application of this method.In this article,we systematically carried out the research on "surface movement and deformation law of coal pillars in super high water filling mining strips" by using theoretical analysis,indoor testing,field measurement,numerical simulation and physical simulation methods in a mine in Jining,Shandong Province.The main results are as follows:Analyzed the actual measured data from the surface movement observation station at the first mining C8301 infill working face in the eight mining area,drew the surface movement deformation curve,revealed the characteristics of surface movement basin and the dynamic change process of surface movement deformation under the conditions of ultra-high water infill mining,calculated various angular parameters of coal pillars in the strip of ultra-high water infill mining.The overrun influence angle is 79.8°,and the maximum sink velocity lag angle is 83.3°.Inverted probability integral method parameters: sinking coefficient: 0.17;horizontal movement coefficient: 0.25;main influence angle tangent: 2.4;mining influence propagation angle: 90°-0.6a;inflection point offset distance is 0.Establish a mechanical model of the stability of the isolated coal pillar in the mining area,and classify the overlying rock structure on the filling workings into overhanging top,semi-overhanging top and fully mobile structure according to the different degrees of damage of the overlying rock structure,and the model provides a theoretical basis for analyzing the mining method of the strip coal pillar in secondary filling mining.The results show that the coal pillars in the strip of infill mining should be mined by jump mining.The safety assessment model of coal pillar in the secondary mining section is established,and the width of coal pillar left in the section of ultrahigh water filling mining strip coal pillar is 8m for theoretical analysis.Physical simulation and numerical simulation were used to study the surface movement and deformation law of coal pillars in the strip coal mining with ultra-high water filling.The study shows that:(1)the overburden movement and surface subsidence can be effectively controlled by jump mining method.(2)The influence of filling back mining filling strength,secondary mining width and filling rate on overburden and surface movement deformation is analyzed,and the relationship equation between the maximum surface subsidence value and each influencing factor is obtained.As the width of strip coal column is certain,the influence of filling rate on surface subsidence is larger,and the influence of secondary mining width and filling body strength on surface subsidence is smaller.(3)When strip coal pillar is retrieved at intervals,it causes less increase in roof and surface subsidence.Based on the analysis of the measured data of the surface movement observatory,physical simulation and numerical simulation,the superposition model is used to propose the prediction method of surface subsidence of strip coal pillar by ultra-high water filling mining,and optimize the layout plan of strip coal pillar filling back mining working face and anticipate the surface movement deformation of mining by combining with the actual mining engineering situation in the eight mining area of a mine in Jining,so as to provide technical support for the mining of strip coal pillar by ultra-high water filling in a mine in Jining.coal pillars in a mine in Jining,providing technical support.There are 66 figures,25 tables and 68 references in this thesis.