Percolation Approach to Determine Filter Criteria in Geotextile Filter Design

AbstractGeotextile filters are used widely in overflow hydraulic structures to prevent long-term particle loss and internal erosion in cohesionless soils. Filter criteria have been proposed and developed for the geotextile filter design. The geometric properties of a geotextile filter typically are described in terms of its characteristic opening size (OF), which should consider the different physical characteristics of the soil being protected. To investigate the filter criteria, this study used a percolation approach to determine the optimum value of OF considering the abilities of geotextile to retain soil, and numerical simulations were conducted of the filter–soil system. Different limit states of the filtration system, considering the retention, permeability, porosity, and thickness criteria, were studied. The statistical fractal method was used to consider the broad gradation of soils and their nonlinear properties, and network models composed of particles and constrictions were generated to simulate the erosion process. The proposed approach can serve as an appropriate guide for the design of geotextile filters applied to the cohesionless granular soils.