Study On Dynamic Construction Mechanics Of Non-Symmetry Neighborhood & Multi-Arch Loess Tunnel In Subway

With the development of western China and the rapid development of urban rail transit, the major cities in western China will build a large number of subway tunnel, groups of loess neighborhood tunnels will soon appear in the west of China. Neighborhood or multi-arch tunnel is a special structure when wiring is difficult, rather than the non-symmetry multi-arch tunnel is under the special conditions of a special structure of the tunnel. This paper focuses on the design of the non-symmetry neighborhood and multi-arch loess tunnel in subway, simulation of the dynamic construction mechanics, including the following.1. Camparing the theory calculated result with the surrounding rock pressure that is in-site measurement,the theory calculated formulas in shallow burial condition have been maked sure2. Bring the Loess properties into the neighborhood tunnel engineering analysis, the traditional Moerkulun manually added joints model and the bilinear constitutive model with vertical joints simulation results were compared with measured values, and it comes to the conclusion that bilinear constitutive model should be adopted for tunnel's mechanical analysis.3. Under the proposed bilinear constitutive model, using plane numerical methods, carry out with and without initial support, different depths, different spacing, comparative analysis of different tunnel shapes.4. By three-dimensional numerical method and monitoring data from experimental tunnel, constructing schemes that include three different construction sequence method, has been studied in dynamic mechanics process. Based on mechanical character of three methods above, countermeasure or optimization is proposed to make the tunnel construction safe. Monitoring method suggests support deformation should be controlled in shallow burial condition.5. The characteristics of Mid-ajacent rock in the non-symmetry multi-arch tunnel was analyzed and summarized.