Study On Technology Of Construction Pre-reinforced And Its Application For Shallow Tunnels Construction Method In Subway

Formation in the process of subway construction stability study is a big problem that weare facing now, mainly displays in the strata subsidence caused by metro construction,instability of surrounding soils, damage to the surrounding underground pipeline, adverseimpacts on the underground excavation surrounding high-rise buildings, which are importantfactors in the subway design and construction. Tunnel excavation after destroyed the originalstress state of surrounding rock, directly may lead to the destruction of the surrounding rockinstability. certain pre-reinforcement measures must be taken in order to maintain a stablestate of surrounding rock. But different pre-reinforcement technology to adapt to the workingcondition is different, so the study of the pre-reinforcement technology for metro hasimportant significance.In this paper, on the basis of full access to a large number of literature, combined with xi’an subway line one sprinkle jinqiao~north street concealed excavation section tunnel of theengineering background, using the Midas GTS to set up model.With no reinforcement scheme,bolt grouting pre-reinforcement, horizontal rotary jet grouting pre-reinforcement, pipe roofgrouting pre-reinforcement analyzed the four conditions are simulated. According to thesimulation scheme of four vertical displacement and horizontal displacement is concluded,pipe roof grouting pre-reinforcement is reasonable support form in big cross section shallowburied loess tunnel.Based on the field monitoring data and the research method of combining the finiteelement numerical simulation based on the field monitoring data and comparing with theresults obtained from the numerical simulation, the applicability of the numerical simulationis verified, also further validates the sprinkle jinqiao~north street of xi ’an subway tunnel advanced pipe roof supporting the construction the rationality of design scheme which is animportant guiding role for similar projects.