Analysis Of The Influence Of Hard Roof On Reasonable Section Coal Pillar Width

In recent years,the control of hard roof in the process of coal mining has been a research direction of the rock mechanics and mining industry.Because such roof rock is hard and well integrated,and the limit of resistance to external damage is large.After mining,it is easy to form a large hanging roof in the goaf,which is liable to cause serious roof accidents.Thus,the retention of the coal pillar in this severe geological environment is very difficult.Although the research on the width of coal pillar has been done many times,many research achievements have been made.However,the problem of the influence of hard roof on reasonable section coal pillar width has become another barrier for experts and scholars in this field.This paper is based on the actual situation of hard roof working face of the Pan three mine 17181(1),through theoretical calculation,numerical simulation and analysis of field observation data,carried out deep research on the reasonable coal pillar working face under hard roof setting problem.Firstly,this paper combines the hard roof caving,the reasonable width of coal pillar and other related theories with the production situation of the mine,so as to further explore the theory of reasonable coal pillar width in hard roof under the research findings of predecessors.Secondly,according to the theoretical calculation,it designs the numerical model,simulated 5m,7m,11m,etc.different width of coal pillar and effect analysis;finally,a comprehensive comparison and selection of coal pillar width for field test.The main mechanical data are recorded and analyzed by setting up several observation stations to verify whether the width of the designed coal pillar is reasonable.From the angles of guaranteeing safety production,reducing unnecessary waste of resources and ensuring the stability of surrounding rock,we have finally determined that the reasonable pillar width of the mine is 7m.The research ideas and preliminary results of this paper can provide a more scientific reference value for the future project of coal pillar under the condition of hard roof.