Study On Rockburst Prevention And Control Technology Of Deep-buried Irregular Working Face In Kongzhuang Coal Mine

With the increasing mining depth and the deteriorating production environment,the degree of rock burst is increasing day by day,and easily occurs in coal pillar stress concentration area and geological structure area.The 7301 working face of the Kongzhuang Coal Mine is arranged along the strike direction of the F12 fault,which is affected by the deep mining depth and the fault structure.The stress field of the original rock is larger,and the irregular layout of the working face is easy to cause stress concentration in the turn area,the shrinkage area and the fault protection pillar area.The 7301 working face is not only affected by high static loading,but also by the overburden fracture,F12 fault and so on.The dynamic loading effect of the activation of derived faults can easily lead to rock burst accidents.For this reason,this paper takes the deep-buried irregular 7301 working face of Kongzhuang Coal Mine as the research object,theoretically analyses the impact factors and dynamic and static load sources of the deep-buried irregular working face,takes 7301 as simulation background to analyse the stress distribution characteristics and combines the microseismic data to analyze the microseismic activity law of the deep-buried irregular working face.At the same time,the monitoring and prevention technology of rock brust hazard in 7301 working face is put forward and applied to the site.The following conclusions are drawn:(1)The rock brust risk factors,overburden structure characteristics and dynamic and static load sources of deep-buried irregular working face are analyzed theoretically.The results show that overburden structure is O-X structure of a single working face,static load source of 7301 working face is self-weight stress,supporting stress and structural stress,dynamic load source is basic roof weighting,overburden movement,fault slip,and multiple force sources are easy to induce impact.The areas with impact risk of 7301 working face in the mining process are mainly concentrated in the initial mining,square,fault crossing and turning of working face.And shrinkage period.(2)The stress distribution characteristics of 7301 working face during mining process are studied.FLAC3D simulation experiment used four stages to reveal the impact risk of working face,which were the initial weighting stage,the"square"stage,the shrinkage stage and the near stopping line stage.From the initial weighting stage to the near stopping line stage,the peak value of supporting stress was distributed about 10-12 m in front of the coal wall and the stress peak value rises from 21.8MPa to 53.28 MPa.The maximum stress concentration coefficient reaches 2.88,and the leading stress level rises significantly;The stress peak value of coal and rock near both sides of F12 fault rises from 28 MPa to 37 MPa,and the maximum stress concentration coefficient reaches 2.31.The stress state of coal and rock mass near F12fault is always at a high level which indicates that F12 fault has a great influence on7301 working face,especially the material channel of working face.(3)Based on the microseismic data of deep-buried irregular 7301 working face during mining,the microseismic distribution and evolution law of 7301 working face are obtained.The microseismic events caused by mining in 7301 working face are mainly those with energy less than 10~3J,and have certain correlation with mining speed.And the process can be divided into four stages by microseismic and the characteristics of microseismic distribution:the initial mining stage,the first square meeting stage,the first contraction stage and the second contraction stage.(4)Combining with the impact characteristics of deep-buried irregular working face,the monitoring and prevention technology of rock burst in 7301 working face is obtained,and the effect test is carried out in time.Through the above measures,the impact danger grade of the working face during mining period is reduced,no microseismic activity with energy greater than 104J occurs,and the rock pressure shows more stable,which ensures the safe mining of the working face.The results gives guidance for 7301 working face and the anti-scour design of adjacent mines or similar working faces.The thesis has 57 figures,15 tables,90 references.