Abstract:Applicability and calculation method of cubic spline interpolation in longitudinal deformation curve fitting of crossriver shield tunnel were analyzed,and longitudinal deformation curve of crossriver 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 crossriver tunnel,relationship under different critical states between longitudinal deformation curvature and circular seam stretchingamount was built.Correlation between longitudinal deformation curvature of crossriver tunnel and circular seam leakage was evaluated,by comparing leakage detection results of crossriver tunnel on site.The results show that critical curvature radius value of crossriver shield tunnel is smaller than metro shield tunnel.When longitudinal deformation curvature radius of crossriver tunnel is less than 2407.1m and its circular seam stretchingamount is more than 3mm,the probability that leakage occurs to the circular seam is relatively high.When longitudinal deformation curvature radius of crossriver tunnel is less than 1 256.8m and its circular seam stretchingamount is more than 6 mm,water sealing measures of circular seam is invalid,and serious leakage may appear in tunnel.