Research On Deformation And Bearing Capacity Of Flexible Support In Weak Rock Masses Tunnel

Recently,with the rapid development of traffic infrastructure,many soft rock tunnels are often encountered around the world accompanied by large deformations.The phenomenons of rock bolt failure,steel arch distortion,shotcrete cracking,etc.greatly challenge the tunnel construction.However,there is no general supporting concept available for soft rock tunnels,and the type of support structure is single,which cannot form a unified deformation system.Based on the project of Dongxishan Tunnel Dachao Highway in Guangdong Provence,China.Guided by the principle,of yield support,a combined investigation of in situ monitory,theoretical analysis and numerical calculation is carried out in this paper.The following conclusion can be obtained as follows.(1)Based on the theory of surrounding rock stress control,the flexible support can reduce the internal force of surrounding rock by releasing the surrounding rock strain energy,and optimize the stress condition of tunnel support structure.(2)Based on the convergence constraint method,by comparing the ground reaction curve and support characteristic curves of rigid support and flexible support,the stress characteristics of flexible support structure are analyzed in this paper.(3)Based on the results of numerical analysis,by comparing with the deformation and stress of the surrounding rock,the internal force of the initial supporting arch,and the internal force of the bolt,the deformation and stress characteristics of the surrounding and the supporting structure is analyzed.(4)Combining with the result of numerical analysis and test,the stress and deformation of the flexible support structure are comprehensively considered.Thefeasibility of the flexible support for the supporting project is analyzed in this paper.