The Numerical Simulation And Analysis Of Construction Of Shallow Buried Covered Excavation On Qingjiang Road Station Of Qingdao Metro

This paper relying on the actual engineering of the Gingjiang road station in Qingdao subway, according to the geological and structural characteristics of the selected subway station, establishing a3D mechanics analysis model of shallow depth excavation of large span subway station with the finite element analysis software ABAQUS, analysis the rock stress field, displacement field of tunnel crossing construction and its rock-structure interaction inner mechanical behavior when construction, and study on the impact of support technology, excavation speed, the excavation method and pavement load to the tunnel excavation.The research shows that when use the ABAQUS finite element analysis software to simulate the excavation of tunnel dynamic construction process, construction of the tunnel excavation and supporting process should be substep, and the length of the no supprtting hole spacing influence the rock displacement release rate, so when carried on the numerical simulation analysis of the tunnel construction, the choice of the reasonable no supprtting hole spacing should be based on the actual construction. In the process of tunnel construction, pipe-roof protection applied makes the physical properties of rock change, and have expansion role on the surrounding soil; when tunnel excavation in the other direction, because of the space effect, the rate of convergence growth is quite obvious, and in the cross of air flue and the station, the tensile stress and compressive stress lining structure of is focused, especially the growth pressure stress is obvious.The results of all kinds of factors on the influence of the tunnel construction research are:(1)The tunnel excavation speed increases, which make the tensile stress of rock and lining structure of increase, pressure stress reduction,but the settlement of vault will reduced, and the arch bottom upheaval value will increases, the surface settlement reduce.(2)Benching tunnelling method relative CRD method construction, the tensile stress and compressive stress of lining structure increase much more, so the influence of excavation method on lining structure stress is bigger.(3)When considering pavement load, the ground surface settlement tank relatively gentle some, and the subsidence value of vault and surface also relatively large.(4)When the tunnel construction, the existence of rock shatter zone make the rock settlement and uplift close to the rock shatter zone relative bigger than the rock amount from rock shatter zone; When the working face excavation to rock fracture zone, the vault sedimentation value, inverted arch elevation value, and horizontal convergence value of the lining structure add obviously.