Study On Simulation Test Of Strip Pillar Stability Under Deep Mining In Tangkou Coal Mine

It is necessary for coal production to turn to deep coal seam,however, the study on predicting and controlling the surface subsidence brought from deep mining was less. In order to realize the safe and high efficient mining, it is obviously significant to study actual load and stability of strip pillar. Based on the geological data and production practice of 230,430 mining area in Tangkou Coal Mine, stability of deep strip pillar was studied by theoretical analysis, field observation, physical simulation test with similar material in three-dimensional bed and numerical simulation, and the main contents and conclusions are as follows:(1)The design principle of mining and reserved size under deep mining was analyzed theoretically, obtaining the size formula of strip pillar:Bq/(1-k)H/(tanβ), A = 0.7H/(tanβ)-B; the shape of saddle is the typical form of stable strip pillar by analyzing pillar force.(2)Vertical pressure and lateral deformation of strip pillar in Tangkou Coal Mine was monitored in field when advancing the working face and being in goaf, studying the stress and deformation characteristics in different areas of pillar. The results show that the concentrating area transfers to the middle of pillar and the range of core zone becomes smaller continually in the process of mining working face before the finish of full collapse.(3)The movement of deep strip pillar was simulated by physical simulation test with similar material in large three-dimensional bed; the evolution and failure law of stress and deformation of pillar was studied by analyzing the monitoring data. It is proved that pillar stress increases non-linearly with fluctuation at the begining of mining and then changes slowly, tending to stability when the working face passes the pillar over 70m.(4)Distribution law of plastic zone width of deep strip pillar was analyzed applying FLAC3D, studying the relationship between plastic zone width and influencing factors. The results show that the width of plastic zone increases along with the increase of mining depth, mining thickness and recovery coefficient, so does the peak value of stress concentration which has a trend of.transferring to elastic core zone of pillar.(5)The plastic zone width of strip pillar in study area under deep mining in Tangkou Coal Mine is smaller than 0.00492 by simulation and calculation, obtaining the actual formula of plastic zone width being suitable for study area under deep mining, that is Y0= 0.00423m H.