Research On Gob-side Entry Driving Surrounding Rock Structure And Deformation Mechanism Under The Broken Rocks Conditions

Due to the impact of high geo-stress,in deep mining of coal,when the surrounding rocks have poor lithology,structural fracture and joint fissure development,will make the surrounding rocks will be broken and increase the difficulty to control.On the background of engineering practice of the gob-side entry driving of the ventilation roadway at 7259 coal face in Renlou coal mine,considering the characteristics of the weak-broken surrounding rocks,this paper is a systematic research on gob-side entry driving surrounding rocks structure and deformation mechanism under the broken rocks conditions,by using theoretical analysis,numerical simulation and field measurement.Firstly from the mechanism of the stability of surrounding rock as the starting point,by building the overlying strata's structural model of the gob-side entry driving,analysis of the displacement and movement laws of overlying strata and the evolution laws of surrounding rocks in different periods,and make a preliminary judge for the driving position of roadway.Secondly,the main parameters of arc triangle were discussed in detail through the analysis of the overlying strata's breaking law of the gob-side entry driving,get the discrimination method of the main roof's fracture line position according to the hanging roof length.Then,by using the theoretical calculation to analysis the best time of driving and the reasonable width of narrow coal pillar.With the FLAC3D numerical simulation analysis software,the simulation results using Tecplot data analysis software for processing,get the stress field and displacement field contour and the distribution of plastic zone in different width of coal pillar and different periods,then determined the reasonable width of narrow coal pillar is 5m.Finally,acquired the surface displacement of driving roadway and the deep base point deformation of roof and narrow coal pillar through the field observation.Based on the analysis of data processing,Show that the width of narrow coal pillar are selected reasonably,the roadway deformation meets the safety requirements,and has improved the stability of surrounding rocks.