Research On Deformation Mechanism Of Metro Tunnel Lining By Mining Method

Recently, construction of Metro is rapidly developed. The frequently used method of metro tunnel construction includes NATM, mining method, shield, cut and cover method, immersed tube method, pipe jacking. Mining method can be due to its low cost, swift construction and non-interruption of traffic and effective control of settlement by supporting measures, mining method becomes the first choice of tunnel construction in the downtown. Construction and Monitoring of modern information leveled efficiency of construction and lower risk of construction. This paper, based on tunnel construction of the second line of rail transports in Wuhan, analyzes mechanical deformation mechanism of lining by structure-load mothod and ground-structure method. It also analyzes application and guidance in practical engineering of the two methods. By numerical simulation, analysis of mechanical behavior of tunnel lining under external loads and general laws of lining deformation are carried out. The main work of this paper is as follows:(1) it introduces methods of tunnel construction at home and abroad. And focuses on the tips mining method and the mining method, differences between other construction methods and its advantages and disadvantages. (2) it introduces the theoretical basis of. structure-load method and ground-structure method. It highlights the continuum model finite element models based on the continuum model and constitutive models of soil and material strength criterion.(3) Combined with the construction of metro tunnel of Wuhan rail transit line 2, this paper introduces the practical use of structure-load method and ground-structure. Using structure-load method, it firstly selects typical cross sections, and researches stress state of the lining. Then by ground-structure method , it simulates steps of tunnel excavation and support, and carries out analysis of tunnel lining in every stage. At least, Comparative analysis of applicability in practical engineering and differences in structural analysis of the two methods are attained.