Stability of supported geomembrane tube flood barriers of novel design

Abstract

Geomembrane tube is an alternative method for the construction of flood barriers, cofferdams and breakwaters for flood risk management. Compared to the traditional method of using sandbags to build flood barriers, geomembrane tubes could be inflated very quickly using water, folded and transported easily after the flood recedes and reused in the future. A method of inserting the L-shaped block on the downstream side of a geomembrane tube is proposed to prevent the geomembrane tubes from rolling off or slipping along the ground surface. Numerical studies using particle flow code (PFC2D) software are carried out to analyse the behaviour of the geomembrane tube supported by L-shaped blocks. Parametric studies are also conducted to identify the influences from the key factors and to provide predictive charts for practical usage. It is found that the optimum edge length of the L-shaped block is 0.12L and the suggested initial pumping pressure is 0.162γL where L is the cross-sectional perimeter of the geomembrane tube and γ is the unit weight of the filling liquid. The suggested central angle of the segment of the L-shaped block is π/3. The geomembrane tube designed using the suggested parameters can sustain and external water level of 0.296L.