Effects of dewatering on adjacent underground pipelines during excavation of deep foundation pit at a metro station in Lanzhou

Taking the deep foundation pit at a subway station of Lanzhou metro line 1 as an example, the displacement of the underground pipes induced by its dewatering is comprehensively analyzed. Using piles and internal bracing structures to support the deep foundation pit and considering dewatering during the whole excavation process, a three-dimensional finite element model is established by using the FEM software ADINA. The FEM analysis and monitoring data show that the deep excavation and dewatering have significant effects on the displacement of underground pipelines. Accordingly the deformation of the pipelines is summarized, so as to provide an important basis for the design and construction of Lanzhou subway stations and similar deep foundation pits.