Study On The Deformation Evolution Law And Control Of Surrounding Rock In Gob Side Entry With Hard Roof Cutting And Filling Of Qinglongtongchang Coal Mine

In order to improve the recovery rate of coal and solve the problem of shortage of mining replacement,the technology of gob side entry retaining has been developed rapidly.In this paper,in view of the serious deformation of the filling body,the large amount of roof separation,the prominent phenomenon of floor heave and the significant deformation of the solid coal wall in the process of retaining the roadway along the gob in 15102 working face of Qinglongtongchang coal mine,the research method of the combination of theoretical calculation,numerical simulation and field engineering practice is comprehensively used to study the parameters of roof cutting and presplitting,filling body and surrounding rock control in detail Key issues such as manufacturing technology.The research results have been applied in Qinglongtongchang coal mine and achieved good economic benefits.The main results are as follows:(1)Based on the study of the basic roof breaking law of gob side entry retaining,the deformation of surrounding rock under the hard roof without roof cutting and under the roof cutting is compared and analyzed,and the effect of presplitting and roof cutting can improve the gob side entry retaining is verified;the influence of presplitting angle and roof cutting height on the roof caving,surrounding rock deformation and vertical stress distribution of filling body are studied by theoretical calculation and numerical simulation respectively,and the final result is confirmed Reasonable presplitting angle and cutting height are determined.(2)The mechanical model of gob side entry retaining considering the hard roof of presplitting blasting is established,and the main mechanical parameters of the side entry filling body of the hard roof of presplitting blasting are calculated theoretically.Then,the influence law of the side entry supporting parameter scheme on the stress distribution and deformation characteristics of the surrounding rock along the gob side entry is studied and analyzed by numerical simulation,and the reasonable side entry filling body width is determined.The mechanical simplification is adopted The results of numerical simulation and analysis show that the prestressed reinforcement components on both sides of the filling body can effectively improve the deformation resistance and bearing capacity of the filling body.(3)Based on the study of the bearing and damage characteristics of the surrounding rock in the gob side entry,it is obtained that the gob side entryexperiences the influence of the breaking and rotating subsidence of the basic roof strata behind the previous working face and the leading bearing stress of the next working face,which is very easy to cause serious deformation and damage of the surrounding rock in the roadway.Based on this,the reasonable supporting technology and parameters in the gob side entry with hard roof are determined.(4)Based on the above research results,through the field industrial test and the observation results of the mine pressure along the gob,it is shown that the determined cutting technology and parameters,the mechanical parameters of the filling body beside the roadway,the support technology and parameters in the roadway effectively control the deformation of the surrounding rock along the gob of the hard top plate in15102 working face of Qinglongtongchang coal mine,and test the reliability and practicability of the research results.There are 76 figures,11 tables and 83 references in this paper.