Two-Dimensional Analysis of Four Types of Water-Filled Geomembrane Tubes as Temporary Flood-Fighting Devices

Abstract

Two-dimensional analysis of four types of water-filled tube dams is carried out: an apron-tube dam, a single baffle tube dam, a sleeved tube dam, and a stacked tube dam. Since the analysis of the water-filled tube dam involves highly nonlinear geometric deformations and interactions with soil, fluid, and structure, it is solved numerically with the explicit finite difference program FLAC. The tube is numerically modeled with beam elements. The predicted contact regions are modeled with interface elements. The Mohr-Coulomb constitutive model is used for the soil. Water inside and outside of the tube is modeled as hydrostatic pressure and the pressures are continuously updated as the configuration of the tube is changed. The change of the internal water pressure head (IWPH) for maintaining a constant tube area during the deformation is simulated. The simulation is achieved by two iterative procedures, the secant method and the factored secant method. The numerical analysis results show good agreement with the experimental results overall: the deformation of the tube(s), the IWPH changes, and the critical external water heights. From the numerical simulation of the experiments and the parametric studies, the behavior of each type of water-filled tube dam is clarified. Also, the failure modes of the tube dams are examined. The failure mode of a tube dam depends on the configuration and IWPH of the tube dam and the characteristics of the soil surface.