Research On The Controlling Theory And Technlolgy Of Excavtion In Loess Stratingraphy In Xi’an Metro

Considering the specific characteristics of loess geologic strata in xi’an, and with the help of soil mechanics theory, it’s analyzed for the constitution law of Stratum deformation and instability caused by tunnel construction, as the background of Xi’an Metro Line2TJSG-13section, from YongNing Gate station to the North Street station. It calculates the pressure of the layers above the tunnel, summarizes and analyzes the process of ground surface settlement, provides the elastic-plastic analysis method of strata deformation and completed the results of numerical analysis. And the formula of the excavation face soil stability supporting force is derived in this paper. According to the formula, the soil mechanics parameters and shield construction parameters which may influence the ground surface subsidence are found and effective technical measures to control of the ground surface settlement was established. These study results were used in the engineering of shield tunnel underneath the ancient building group such as the walls and moat of the YongNing Gate as well as the Clock Tower and the construction methods and construction process were guided. The surface subsidence monitoring data feedback proved the correctness and effectiveness of the construction method and process management.