Study On Theory And Technology Of Staged Support In Coal Mine Roadway Excavation

In the existing coal mine tunnel excavation process,a complete support is adopted.After tunneling,all the supports are completely protected,which makes the support tired.The time required for each excavation in the tunneling is significant.The serious reason is that the tunnel There are time and space effects in the driving process,namely,the time effect of the bounding of the driving face and the change of the surrounding rock.The deformation of surrounding rock and load release in the roadway is not completed at one time,but gradually released with the advancement of the excavation surface.Therefore,according to the characteristics of surrounding rock load gradual release in the tunneling process,the idea of roadway anchor rod is put forward,and the driving speed of the roadway is improved by changing the support link and method.The main conclusions of the study are as follows:(1)Analyze the factors that affect the speed of tunneling in coal mines,mainly from the four aspects of geological conditions,tunneling equipment,construction organization and management,and unbalanced tunneling and support.The main characteristics of each factor are discussed,and various links of tunneling are analyzed through on-site investigations.As a percentage of time,it is concluded that support is the process that takes the longest time.Therefore,the speed of roadway excavation can be increased by changing the support links and methods.(2)Due to the influence of time and space effects of roadway excavation,the surrounding rock deformation and load are gradually released as the driving face advances.The existing roadway support design adopts one-time full support technology,ignoring the time and space effects in the driving process,and does not fully consider the roadway.The deformation characteristics and load release characteristics of the surrounding rock make the bolt(cable)support time too long,which seriously affects the tunneling efficiency of the roadway.This paper analyzes and summarizes the space effect of the driving surface constraint and the time effect of the surrounding rock creep that affect the surrounding rock deformation and load release of the roadway.Speed of roadway excavation.Because of the one-to-one correspondence between the surrounding rock load and the surrounding rock deformation,the released load can be inversely calculated through the surrounding rock deformation.Therefore,a method for monitoring the surrounding rock deformation of the driving roadway,the method of solving the law of surrounding rock load release,and the supporting parameters and supports are given.Design method of protection scheme.(3)Establish the mechanical model of the driving roadway and derive the relationship between the surrounding rock deformation and the released load as the driving face advances.According to the on-site surrounding rock deformation monitoring data,the surrounding rock load release law can be inversely calculated,and the support plan can be carried out based on this design.Through the analysis of calculation examples,the surrounding rock load release is small near the tunneling face,and a small number of anchors can ensure the stability of the tunneling space.The remaining anchors support without affecting the tunneling,so as to reduce the tunneling process.The supporting time of the middle anchor rod(cable)achieves the purpose of increasing the tunneling speed..(4)Based on the N1214 auxiliary transport and excavation roadway of the Ningtiaota,the support design is carried out with the idea of graded support,and a set of graded support construction plan is formed.Through on-site monitoring,the graded support plan is compared with the original support plan.The graded support plan can not only maintain the stability of the roadway,but also reduce the support time and increase the speed of the roadway.Through the study of sub-support design,it can provide theoretical guidance for the support of driving roadway,and the research results have theoretical significance and engineering value.