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The leakage of shield tunnels built in confined aquifers of silt or fine sand may result in the erosion of soil. Due to the loss of ground support, significant distortions of the tunnel structure may arise. As an initial insight into the mechanisms driving disaster chains, the erosion morphology of silt or fine sand under converging flow should be made clear first. In this study, a series of laboratory tests were performed to investigate the erosion morphology of fine sand under converging flow and its spatiotemporal evolution. Notably, for consistency with practical engineering, the initial effective stress of the soil was also considered. The initial results indicated that the erosion process may involve the soil arching effect due to the presence of soil effective stress. On this basis, tests with two leakage points were conducted. It was found that successively opening the two leakage points may lead to a larger erosion area of superposition when compared with the case of simultaneously opening two leakage points. [ABSTRACT FROM AUTHOR]