Analysis Of Impact Of Groundwater In Coastal City Subway Project

With the advance of urbanization of society and the shield construction technology continuing to mature,shield-method is applied in the coastal city of three dimensional development more and more.Construction of non-precipitation method,by controlling water seepage during tunnel excavation,can effectively reduce the formation of the consolidation settlement,making the tunnel construction of a promising direction.In the subway project survey,design and construction process,water issue has always been an extremely important issue, especially in shallow coastal city of groundwater,chemical composition and complex features has a significant impact in the construction.Therefore,a comprehensive understanding of coastal ground water hydrogeological conditions,to carry out the subway construction ground settlement,to analyze ground water corrosion on the subway structure has an important practical significance.In this paper, subway construction process flow-mechanical model,using explicit finite difference software FLAC2D,analyze the ground settlement in range from Jin Chi Road to Li Zhuang of non-precipitation method works. The results show that the non-precipitation construction led to the largest settlement on the invert,the settlement amount of 16.9mm; maximum surface subsidence of 15.7mm,settlement trough width of 60m. Meanwhile, the study of the permeability coefficient of the consolidation settlement of soil is carried out, validation of permeability coefficients of constant treatment is reasonable.With combination of groundwater quality in Tianjin survey data, water corrosion on the subway project is analyzed and evaluated:dive on the concrete structures are generally not corrosive or has a weak corrosion,confined water on the concrete structures generally have weak or moderate corrosion, individual section with strong corrosion;diving and confined water on the concrete generally have weak or moderate corrosion.