Study on the Impact of Subway Shields Tunnel Constructionon Pile Foundation of Adjacent Overpasses in Soft and Weak Ground

Lulu Zhang
Department of Railway Engineering , Baotou Railway Vocational & Technical College，Baotou，014000,China

Abstract:

Technology of shieldtunnelling has been extensivelyutilized incutting-edgemetropolis subway machineconstruction, however, because of the restriction of citycreation land resources; it's miles inevitable for the brand newconstructingsystems convicted with present one. Thus, its milescritical to taking accurate measures to assure the protection of present structure. In this case, a standard case of metro guard tunnel crossing thrumetropolis overpass bridge piles underpinning creationchallenge is studied via way of means of the numerical techniqueand placement ?eld monitoring.Safeguard passages will unavoidably go through viaduct piles at a nearby distance because of the broad development of metros and viaducts in the city. To guarantee the design wellbeing of the existed overpass bridge during the pile foundation underpinning construction, a numerical simulation model is laid out which thinks about the entire establishment supporting construction and development steps. The Numerical Simulation result shows that the pressure and the settlement of the piles establishment supporting design are sensible. After the contrasting of the site observing information and the mathematical model re-enactment results, it is observed that the site settlement and stress results are profoundly steady with the determined outcomes, and it demonstrates the plausibility of the piles establishment supporting development conspire. At last, the site checking settlement information of the bridge wharf and the pile cap show that the first bridge structure is scarcely impacted by the safeguard burrow development, the development technique can give reference and experience to the future comparative ventures. The analytical results indicate that the grouting protection wall can e?ectively reduce the pile displacement; especially the grouting depth is 3m below the bottom of the tunnel. Moreover, the L-shaped grouting protection wall can e?ectively reduce the longitudinal displacement of the piles. The present ?ndings might give a reference to the plan and development of safeguard burrows going through viaduct piles.