Analysis Of Influencing Factors And Control On Driving Speed Of Coal Roadway In Hulu Su Coal Mine

Based on the engineering geological conditions and a large number of observation data,the key factors restricting the driving speed of the coal roadway are determined,By means of theoretical analysis,numerical simulation and industrial test,analyzed the mechanism of the development of Split in laneway's side,the influence of the material properties,the initial pre-tightening force and the supporting lag time on the deformation of the roadway is studied,on the basis of the above,the paper puts forward the method of controlling the splitting of the roadway,and carry out the industrial test successfully.The main conclusions are as follows:(1)The key factors affecting the driving speed of the coal roadway is:roadway spalling leading to the construction time of bolt at the middle of the roadsides is 4 times of the normal anchor bolt,which seriously restricts the tunneling speed.(2)The deformation of roadway coal mass can be divided into 4 stages,they are the formation of cracks,the extension of cracks,the coalescence of cracks,and the stage of restabilization.Based on the mechanics model of crack like structure,the critical load is obtained,the critical buckling load of the slab like structure is related to the height of the plate like structure ? and self stiffness D,the lower the plate structure height is,the lower the stiffness is,the easier it is to lose stability.(3)The numerical simulation of the relationship between Roof supporting strength and the spalling shows that: the two corners of the roadway are subjected to eccentric pressure,the increase of roof supporting material and supporting pretightening force can effectively increase the elastic modulus of the roof,which can reduce the deformation of roadway,and reduce the peak value of abutment pressure,and make the two support pressure transfer to the depth of the coal wall,and improve the maintenance condition of the roadway.(4)The numerical simulation of the relationship between the time effectiveness of the support and the spalling shows that: timely support to the surrounding rock control effect is the best,the effect of lagging 4 h surrounding rock control becomes worse,Especially the two sides of tunnel deformation is larger,the control effect of the lag 8 h surrounding rock is the worst,the deformation of the tunnel is especially obvious.The influence of the lagging supporting time on the roof and floor of the roadway is more serious than that of the two roadways;at the beginning of the roadway excavation,the plastic zone increases slowly,the longer the support lag time is,the deeper the roadway falls into the top-bottom deformation,and the faster the deformation rate of the roadway will be.(5)The industrial experiment was successfully carried out in Hulu Su Mine,the monitoring results show that the deformation of the tunnel is improved obviously with the improved support scheme,the average spalling depth is 97 mm,far less than the original supporting 300-400 mm spalling depth,roof subsidence maximum subsidence is 22 mm,less than the original supporting scheme of 61 mm,indicated that the increase of roof support strength,increase the roof pretightening force can effectively control the deformation.With the increase of the lagging supporting time,the horizontal stress and vertical stress peak value of surrounding rock increase gradually,and the peak value of vertical stress continuously transfers to the deep wall rock.Due to the change of geological condition,resulting in roof rock cutting thickness close to 1 m,cutting time is two times as much as the original time,the average speed of the roadway is 10.3 m.If the coal cutting time is calculated according to the original time,the conversion speed is 640 m/months,the roadway speed has been increased by 30%,it is clear that the adoption of the new scheme can significantly improve the construction speed of coal roadway.