Study On Reasonable Size Of Coal Pillar In Main Road Of Anshan

The stability and reasonable width of pillars for protection of large roadways are of great significance for the maintenance of large roadways,safe and efficient production,and the improvement of the recovery rate of coal resources.The paper takes the coal pillar of No.5-2 coal seam protection in Anshan coal mine as the research object,takes the 2010 working face as the research and test area,and studies the engineering geological conditions of Anshan coal mine through indoor similar material simulation,numerical simulation calculation and comprehensive analysis.The instability mechanism of coal pillars,the distribution of supporting stress,and the optimization of the protective pillar width are all supported in the protection of coal pillars.Finally,the reasonable size of pillar protection coal pillars in Anshan coal mine is determined.The overburden structure model was established through the two stages of protecting the coal pillars:roadway excavation and working face mining.The basic roof rock fracture pattern and its movement deformation law were analyzed,and the stability and overburden load of the pillars in different stages were obtained.The relationship between the top structure size and roadway support.By analyzing the deformation of key blocks and the effect of key blocks on the stability of the spacing pillars,it is concluded that the basic condition for the stability of coal pillars is the existence of elastic cores with a certain width inside the pillars,and the movement of the overburden is obtained.State and effect on stability of coal pillars.The theoretical analysis method was used to study the distribution law and dynamic evolution of abutment pressure on the working pillars.The study showed that the basic condition for the coal pillars to remain stable after the coal seam was produced was the existence of an elastic core area.There are fracturing zone,plastic zone and elastic core zone;"saddle type”is the typical stress state of coal pillar stability,and "arching”is the typical stress state distribution form of coal pillar instability failure.Using the elasto-plastic limit equilibrium theoretical calculation method,the reasonable width of coal pillar protection in Anshan coal mine is calculated to be 39m.Considering safety and reliability,theoretical calculations show that reasonable coal pillar width of Anshan coal mine should not be less than 40m..Through physical and similar materials and numerical simulation studies,when the width of the coal pillar is 45m,there are no obvious cracks in the coal pillars and the surface,and there is a large nuclear area in the coal pillars.When the pillar width is 42m,the stress concentration factor reaches 3.45,and the entire pillar is Due to plastic failure,the coal pillars are in an unstable state.Therefore,the results of the simulation study suggest that the width of coal pillars in the Anshan coal mine shall be no less than 45m.Finally,in the field engineering application,it is shown that under the mining geological conditions of the Anshan coal mine,when the width of the pillar protection coal pillar is 45m,it is safe and reliable.