Research On Reasonable Coal Pillar Width And Surrounding Rock Control Of Roadway Driving Along Goaf In Xutuan Coal Mine

Deformation control of surrounding rock in gob-side entry driving is the key of gob-side entry driving technology.Taking 3238 working face of Xutuan Coal Mine as the research object,this paper studies the technology of retaining reasonable width coal pillar and surrounding rock control in gob-side entry driving from theoretical analysis,field investigation and numerical simulation.First of all,through literature research,we know the current research situation at home and abroad on retaining narrow coal pillars in gob-side entry driving,and formulate the research direction,research objectives and tasks of this paper.Secondly,we have a certain understanding of the geological conditions of 3238 working face in Xutuan coal mine through on-site investigation.From a theoretical point of view,we establish a caving movement model of overburden rock in gob-side entry driving,analyze the movement law of overburden rock caving structure,and theoretically calculate the reasonable width of coal pillar.Using numerical simulation software,the distribution characteristics of plastic zone,stress field and displacement field of surrounding rock in gob-side entry under the condition of different width coal pillars are simulated for 3238 working face in two stages of roadway excavation and mining.Secondly,the grouting reinforcement mechanism and grouting material selection of small coal pillar are analyzed theoretically and field experiments are combined to determine the appropriate grouting timing and grouting material.Finally,the surrounding rock control countermeasures suitable for changing the geological conditions of the working face are given,and the rationality of grouting reinforcement support countermeasures is verified through field engineering experiments.This paper mainly studies the problem of reasonable pillar width and surrounding rock control technology in 3238 gob-side entry driving in Xutuan coal mine,and obtains the following results:1)Based on the knowledge of rock mechanics and mine pressure science,the structural model of gob-side entry is established,and the "O-X" type fracture of the basic roof is analyzed as the working face advances.The stability of gob-side entry driving is determined by the interaction between the large structure formed by the collapse of the old roof and the small structure formed by the surrounding rock of the entry.2)By means of numerical analysis,the damage of coal pillar,the stress distribution law of roadway and the change characteristics of surrounding rock displacement in 3238 working face under the influence of multiple mining are studied,which provides the basis for determining the position of 3238 gob-side roadway and the width of coal pillar.Combined with the field actual mine and numerical simulation results,it is determined that 3238 gob-side roadway driving with 5m narrow coal pillar is the most suitable.3)The mechanism of coal and rock mass grouting reinforcement is theoretically studied,and through the briquette proportioning experiment,the reinforcement effect of the existing grouting materials and the special cement for coal pillar grouting are compared and tested,and finally the materials suitable for gradual reinforcement of 3238 wind tunnel are determined.4)Through theoretical analysis and drilling peeping results,the grouting reinforcement mechanism and reasonable timing are studied,and the grouting effects of several grouting materials are compared from the two angles of uniaxial compression and solidification time by using briquette embryo cloth experiment,and finally the appropriate grouting material and slurry usage ratio are determined.5)Based on the results of numerical simulation and field experiments,a set of grouting reinforcement scheme for 3238 working face is put forward and applied to field industrial experiments.On-site monitoring has verified the rationality of grouting reinforcement support scheme,and the deformation of coal pillar and surrounding rock of roadway is within the controllable range.Figure 57 table 11 reference 80...