Stacked geomembrane tubes for flood control: experiments and analysis

Geomembrane tubes are used in a number of applications to withstand external water, such as for water diversion or impoundment, or as cofferdams. Stacked geomembrane tubes have been applied in place of sandbags for flood control. The behavior of a stack of one tube on top of two tubes is investigated here, through experiments and numerical analysis. The tubes are inflated with water. The maximum external headwater level that the dam can resist depends on various conditions. Underseepage and piping in the soil foundation may cause failure of the dam, which can be alleviated by appropriate design of a drainage layer under a portion of the structure. Rolling and sliding of the tubes are other possible failure modes. The finite difference program FLAC is utilized to model a cross-section of the dam and soil. Deformations, tensions, and pore pressures are computed and compared with results from the experiments. The maximum headwater level that can be resisted is about 70% of the height of the dam.