1.School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo ,China;2.Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region(Henan Province),Jiaozuo ,China;3.Technology Platform of Deep Mine Strata Control and Methane Drainage for State Administration of Work Safety,Jiaozuo ,China;4.College of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo ,China;5.State Key Laboratory Cultivation Base for Gas Geology and Gas Control,Jiaozuo ,China;6.Coal Management Bureau of Yaozhou District,Tongchuan,Tongchuan ,China

In order to investigate the existence of pressure arch around coalbed borehole,the fluid-solid coupling dynamic model of coal containing gas based on Hoek-Brown criterion was established and solved by COMSOL software.Then,the distribution law of principal stress and the strain energy density of coal body around borehole before and after drilling in coal seams was analyzed,the variation characteristics of horizontal displacement of coal body with different structure around borehole,the inner boundary and thickness of pressure arch were studied.Furthermore,the characteristics of pressure arch was discussed combined with the distribution law of plastic zone of coal body around borehole.Research results show that pressure arch exists at the top and bottom of coalbed borehole,the arch springing and abutments locate on both sides of borehole.The changing trend of horizontal displacement of coal body around borehole in pressure arch area is relatively gentle.The inner boundary and thickness of pressure arch can be used as two indexes to evaluate the stability of coalbed borehole,and they all decrease gradually with the increase of GSI value,that is,the more complete the coal structure is and the higher the strength is ,the smaller the pressure arch range is.When GSI value is

国家自然科学基金资助项目（51404093）；河南省瓦斯地质与瓦斯治理重点实验室—省部共建国家重点实验室培育基地开放基金项目（WS2012A09，WS2017B11，WS2017A01）；河南省博士后科研资助项目（2017014）；河南理工大学博士基金资助项目（B2008-15，B2012-093）