Analysis of Uplift Failure for Large Lined Canals based on Seepage-Stress Coupling Theory

Abstract

The foundation under large-scale water delivery canals is saturated because of long-term leakage. Uplift failure could be occurred by the excessively reverse seepage pressure gradient in the soil foundation and linings when an emergency water stop. To systematically explain the mechanism of this uplift failure and the process of destruction, a seepage-stress coupled was established with the assistance of COMSOL software. Moreover, the permeability resistance of the geomembrane was conduct with non-thickness interface element. Then cast in place and prefabricated lining canals with the increase of permeability of geomembrane were conduct in this paper. The result calculated based on practical engineering indicate that either intact geomembrane or intact concrete liner exhibit well impermeability so as to prevent uplift failure. The critical value of permeability for avoiding uplift failure is between 1×10-8 m/s and 1×10-10 m/s for prefabricated lining canals. The seepage deformation of foundation soil has a significant effect on the lining stress. These research results can provide reference for further research and prevention on uplift failure problems.

Keywords: Uplift of canal, uplift failure, seepage and stress coupling, geomembrane permeability resistance