Research On The Application Of The Construction Method Of The Cantilever Tunnel Boring Machine For The Urban Rail Transit Tunnel In The Mountainous Area

Taking Guiyang Rail Transit Line 1 as the background,the different construction methods of cantilever tunnelling machine used in the construction of urban tunnel track in mountainous areas are analyzed and studied by field investigation,theoretical analysis,physical model test and numerical simulation test.The main research work is as follows:1.The advantages and disadvantages of the construction of the cantilever roadheader at home and abroad are analyzed,and the excavation mechanism and existing problems of the cantilever roadheader are studied.2.Study the adaptability of different construction methods of urban rail transit tunnel in mountainous area,and put forward the evaluation index of construction methods for the follow-up physical model test and numerical simulation method.3.Through shear experiment,triaxial experiment,knife ring experiment and dynamic elastic test experiment,the physical and mechanical property parameters of the simulated material are tested,and the mix proportion is designed.According to the mass ratio of barite powder,quartz sand and vaseline 12:5.5:1,the tunnel surrounding rock is simulated.The material with the mass ratio of water,gypsum powder and barite powder of 1:1.7:0.2 is used to simulate the initial support of the tunnel.4.The physical model test and numerical simulation test of different construction methods are carried out.It mainly monitors the stress of surrounding rock,surface settlement,horizontal and vertical displacement of tunnel face,calculates the shear safety factor of surrounding rock,and analyzes the influence of the size of plastic zone of surrounding rock on the stability of surrounding rock.5.Comprehensive analysis of physical model test and numerical simulation results to study the mechanical characteristics of different construction methods of urban tunnel track in mountainous area by using cantilever tunneller.6.Study the disturbance of tunnel surrounding rock caused by different construction methods.The results show that the disturbance of three stepsconstruction to surrounding rock is small.