Support Performance Of Lattice Grider Reinforced Shotcrete In Silty Clay Tunnel

With the rapid development of national economy,the rapid increase in traffic tunnel construction in China,accompanied with the process of urbanization,urban subway tunnel increase at the same time."New Austrian method "because of its bearing capacity can give full play to the surrounding rock in the subway tunnel construction process has been more and more widely used,in building facilities with the urban subway tunnel construction will inevitably produce disturbance to tunnel surrounding rock,cause settlement of surrounding rock deformation and surface at the same time.When the surrounding rock deformation and surface settlement of tunnel exceed a certain limit,tunnel construction will inevitably endanger the safety of surrounding buildings,urban roads and underground pipelines.So,choose the reasonable type of primary support is important for the design and construction of the tunnel,the primary support to incorrect way,or the strength of the support member is insufficient,will cause great influence to the safety of tunnel construction,therefore reasonable use of initial supporting type to control the surrounding rock and ground surface deformation is worth our further study.With Haerbin metro line 1 Tongjiang road station～Hanan station underground tunnel as the engineering background,using the theory of elastic thin shell to establish "lattice grider reinforced shotcrete" supporting mechanics model of composite structure,analyzed its support mechanism and using certain conditions in the early structure bear the load size;Monitoring method was adopted for the line tunnel surrounding rock deformation and surface subsidence monitoring analysis,at the same time to carry out the field test,the test section of"lattice grider reinforced shotcrete" initial support member internal force and surrounding rock pressure monitoring test,the combination supporting structure of the surface subsidence and deformation of tunnel surrounding rock control effect,and the "lattice grider reinforced shotcrete"primary support the stability of the composite components.By using finite element software ABAQUS to carry out numerical experiments,the Haerbin metro line 1 in Tongjiang road station～Hanan station underground tunnel excavation by up and down the steps method and "lattice grider reinforced shotcrete" numerical simulation for the process of primary support and the test section of tunnel excavation support after the surface settlement and arch sedimentation of surrounding rock and the changing rule of the convergence of surrounding,at the same time supporting structure in the early new combination"lattice grider reinforced shotcrete" mechanical characteristics.Field test section using the elastic theory method and combined with case of "lattice grider reinforced shotcrete" structure to load calculation,at the same time change the combination of early structure supporting parameters,study the effects of parameter changes on supporting effect,thus related countermeasures are put forward.