Application Of Pipe Roof Pre-support Technique In Xi’an Metro

With the rapid development of urbanization, the traffic in cities are facing more and morechallenges. Because of the restriction of the city scale and the increasing city population, theground traffic is more and more difficult to develop. Xi’an is the focus of the internationalmetropolis construction in Northwest China. While cities are continuously developing andadvancing, the problem of traffic jam is also becoming more and more obviously.Constructing subway and developing underground rail transit has been crunch time.Taking the running tunnel of Sajin Bridge to North Street interval of Xian metro LineNO.1as the engineering background，this paper conducts the research of application of riperoof pre-support technique during tunnel excavation in loess area. The paper uses the methodof combing the field monitoring, theoretical analysis with finite element numerical simulation.Through getting data by means of field monitoring and then analyzing them0, the paperanalyzes the cause of surrounding rock deformation and the supporting principle of pipe roofpre-support. The paper sums up the mechanism and several elastic mechanics model of piperoof pre-support and analyzes the design of pipe roof parameters in detail. Project overviewand hydrogeological conditions on the interval tunnel are introduced and bad soil layers andgeological phenomenon in the construction layer are analyzed. The paper a lso analyzes theengineering and hydrological geological conditions of the running tunnel. Based on theconstruction parameters in construction site, the paper conducts the finite element numericalsimulation of the construction process of pipe roof pre-support and the interaction of pipe roofand the surrouding rock to verify the function that the pipe roof pre-surpport imposes on thestability of surrounding rock. The paper processes and analyzes the monitoring data andcoMPares the data with the values of finite element calculation to verify the rationality of thedesign and construction of pipe roof reinforcement in interval tunnel. Pipe roof pre-support technique is one of the main auxiliary construction methods ofsubway tunnel construction. Study on application of pipe roof pre-support in loess tunnel hasthe vital significance to the the construction of underground engineering in northwest loessregion in our country.