Study On The Parameter Optimization Of Concrete-filled Steel Tube Structure In Loess Road Tunnel

Primary support is the main supporting structure of the tunnel, especially in the loess tunnel. The loess highway tunnel surrounding rock has large and long deformation which lead to the some problems such as lack of supporting stiffness and lining cracking. These problems greatly increase the safety hidden trouble in the tunnel construction. So to explore the arch structure which has large stiffness, strength and strong mechanical as the early stages of the loess highway tunnel supporting structure is of vital importance. Based on this idea, this paper puts forward using the which has a greater stiffness and large force advantage to replace the traditional steel frame supporting structure.On this basis, this article adopt the theoretical calculation to contrast and analysis the stiffness of the traditional steel frame supporting and the big diameter concrete-filled steel tube arch structure, at the same time, take the ANSYS finite element to analysis the supporting effect and mechanical characteristics of the both. Highlight the big diameter concrete-filled steel tube as a new type supporting structure of the loess highway tunnel, has significant advantages in the stiffness and stress characteristics. So it can better control the deformation of the surrounding rock. For its characteristics of Mechanical major, it can also reduce the burden of the secondary lining indirectly, improve the problems of large and long time deformation in the loess tunnel.To parameter and design the local structure before the initial supporting applied to construction. Then adopting ANSYS finite element software to select the reasonable section of the supporting structure, optimize the of the node casing on the structure, determine the reasonable node position and casing parameters, which ensure that the structure can achieve higher support efficiency under the certain parameters. Then compare and analysis the flange of concrete filled steel tube and supporting spacing parameters influencing on supporting effect. Through the deformation of surrounding rock under different parameter combinations, highlight the supporting spacing influencing significant to the supporting effect, then determine the better optimal combination of flange and the supporting spacing.