Western Han Highway, Arch Finite Element Analysis Of Tunnel Support Structure

With the fast development of freeway construction to the western mountainous area in our country, the freeway tunnel construction had already become a expressway construction important component, but in highway construction process as a result of construction plant, special geological and topographical condition limit, the ordinary separation formula tunnel already could not meet the needs which to a certain extent of the freeway constructs, therefore for in aspects of and so on highway line type, technical economy meets the needs which well the modern highway constructs the arch tunnel has already been widely used by the general tunnel technology workers. But repetitious stress distribution of wall rock will be caused by the arches tunnel's construction, causing the arch tunnel with complex stress. Meanwhile being unable to learn the stress of wall rock accurately which a arch tunnel each construction step will bear. Therefore, in the process of the design and construction of arch tunnel,we'd better to learn some bearing capacity and transmutation of the supporting structure in order to instruct the design and construction and ensure the structural security of arch tunnel. To confirm the restraining section of the primary support, and secondary support of arch tunnel is very important to the stability of the whole supports, but the standard had not mentioned that should calculate the position the exact location, therefore discovers the design control section of the supports have vital significance. In view of this goal, this paper take one arch tunnel of Xi'Han freeway as the disquisitive background, meanwhile linking the "Highway tunnel Design Standard" (JTG D70-2004), to come out the numerical simulation of the arch support structure and the surrounding rock deformation, the major elements as the following:(1)Arch tunnel on the impact of factors related to the stability of composite lining was discussed, and according to the different depth of the tunnel, establishing several different load structure calculations.(2)ANSYS software simulation of the arch tunnel excavation and support structures of the finite element method were researched. Taking the construction method named "middle heading method" as an example according the calculational theory of stratum-structure, a 2D elastic-plastic numerical simulation of excavation process and the primary support effect of arch tunnel was carried by ANSYS software. Load structure method was used for the lining of the secondary support's long-term safety assessment. Through the simulation, to determine the position of design control section of primary and secondary support of the type of overall straight center pillar arch tunnel and analyze the mechanical behavior of center pillar. During the analysis, while the relevant calculations and specifications were compared, from an economic point of view, the thickness of the secondary lining can be properly reduced, under the condition of structural stability.(3)According to the results of field measurement data, we compared the numerical simulation of the support structure of the tunnel system and the rock. From this compared analysis, this paper reveals the influence of calculation parameters of numerical simulation and shows that the construction field test parameters on the importance of guidance.Through this research, this paper has the guiding significance to the design and construction of the similar projects to some extent.