Research On Graded Support And Rapid Excavation Technology Of Bolt(Cable) In Coal Mine Roadway

In the process of coal mine tunneling,the tunnel support speed is far behind the tunneling speed.The bolt(cable)support time accounts for 60-70%of the entire tunnel formation time,and the tunneling and anchor(cable)support cannot completely parallel operation severely restricts the rapid tunneling.Due to the "space+time" effect of the roadway driving face,the deformation and stress release of the surrounding rock of the roadway cannot be completed at once.Based on the "space+time" effect of the driving face,this paper starts to study the deformation and stress release of the surrounding rock of the roadway during the driving process,and puts forward the idea of the stepped support of the roadway bolt(cable)in order to increase the speed of the roadway.The main conclusions of the study are as follows:(1)This paper analyzes and summarizes the deformation and failure types of surrounding rocks and the deformation characteristics of surrounding rocks,and describes the "space+time" effect of driving face from the perspectives of physical effect,mechanical effect and time effect.Under the influence of "space+time" effect of excavation surface,the longitudinal deformation forms of surrounding rock can be roughly divided into stable deformation type,continuous deformation type and accelerated deformation type.(2)The existing support design of coal roadway all adopts the support technology of primary roadway formation.The support time of bolt(cable)is too long,the space-time effect of excavation face is ignored,the deformation characteristics of surrounding rock of roadway are not fully considered,and the support concept is not suitable for the rapid tunneling of roadway,which seriously affects the tunneling efficiency.According to the influence of"space+time" effect on roadway tunneling face,the idea of bolt(cable)support in coal roadway is put forward in order to reduce the supporting time of bolt(cable)in the process of roadway tunneling,so as to improve the speed of roadway tunneling and realize the rapid tunneling of coal mine roadway.(3)The mechanical model of the tunnel is established under the spatio-temporal effect,and the mechanical analysis of the tunnel is carried out through elastic-viscoelasticity,and the variation law of the deformation and stress of the surrounding rock with space and time during the tunnel is deduced.With the advancing of the driving surface,the stress release of the surrounding rock of the roadway gradually increases,and the deformation of the surrounding rock and the radius of the plastic zone gradually increase.Through theoretical analysis,near the excavation face,the deformation and stress release of the surrounding rock are small,and a certain number of bolts are supported closely to the working face to ensure the safety and stability of the driving space.The remaining bolts are carried out without affecting the driving.Supporting,reducing the supporting time of the anchor rod(cable)during the driving process,improving the driving efficiency of the roadway,and realizing the rapid driving of the roadway.(4)Taking the NingTiaota S12001 tunneling roadway as the background,combined with specific stratigraphic parameters,the support design was carried out by using the thought of fractional support,and a set of fractional support construction technology was formed.The theoretical calculation results are compared with the field measured data to verify the correctness of the theory.The fractional support scheme can not only effectively control the deformation of surrounding rock and ensure the safety of tunneling space,but also reduce the supporting time of anchor bolt(cable)in the process of tunneling and improve the tunneling efficiency.