Abstract:Applicability and calculation method of cubic spline interpolation applied in longitudinal deformation curve fitting of cross-river shield tunnel were analyzed, and longitudinal deformation curve of cross-river shield tunnel was fitted by using cubic spline interpolation method, and longitudial deformation curvature of whole tunnel was calculated by curve fitting equation. Based on longitudinal structure analysis model of cross-river tunnel, relationship under different critical state between longitudinal deformation curvature and circular seam stretching-amount was built.Correlation between longitudinal deformation curvature of cross-river tunnel and circular seam leakage was evaluated, by comparing leakage detection results of cross-river tunnel on site. The results show that critical curvature radius value of cross-river shield tunnel is smaller than metro shield tunnel. When longitudinal deformation curvature radius of cross-river tunnel is less than 2407.1m and its circular seam stretching-amount is more than 3mm, the probability that leakage appear in circular seam is relatively high.When longitudinal deformation curvature radius of cross-river tunnel is less than 1256.8m and its circular seam stretching-amount is more than 6mm, water sealing measures of circular seam is invalid, and serious leakage may appear in tunnel.