Hydraulic Performance of Conventional and Conical Geotextile Units Filtering Two Highway Soils

• Published in: Geotechnical and geological engineering 2024-06, Vol.42 (4), p.2623-2640
• Main Authors: Ryoo, S. C., Aydilek, A. H.
• Format: Article
• Language: English
• Subjects: Backfill; Charts; Civil Engineering; Computational fluid dynamics; Discrete element method; Drainage; Drainage systems; Earth and Environmental Science; Earth Sciences; Filtration; Fines; Fluid dynamics; Geotechnical Engineering & Applied Earth Sciences; Geotechnical fabrics; Gravel; Hydraulics; Hydrodynamics; Hydrogeology; Laboratories; Mathematical models; Mitigation; Numerical models; Original Paper; Permeability; Piping; Pore pressure; Pore water pressure; Retaining walls; Soil; Soil permeability; Soil types; Soils; Terrestrial Pollution; Waste Management/Waste Technology
• ISSN: 0960-3182; 1573-1529
• DOI: 10.1007/s10706-023-02694-0

More than one-third of highway retaining wall failures around the world occurred due to missing or inadequate drainage systems. A research study was conducted to determine the performance of a recently developed pore pressure mitigation system through the usage of conical geotextile units filtering retaining wall backfill soils used in highway environment. A numerical model based on a computational fluid dynamics and discrete element method (CFD-DEM) coupled approach was developed to simulate particle movement in the soil and piping through the geotextiles. The model was used for conventional as well as conical geotextile filter systems that use woven and nonwoven geotextiles filtering marginal backfill soils with high fines contents and a common gravel backfill material. Both soil-geotextile contact zone and system permeabilities were influenced by varying fines content in the backfill material. Conical filter usage increased the system permeability up to 2.6 times, while piping rates increased up to almost 10 times as result of conical filter usage. A retention ratio successfully predicted piping rates for different types of woven and nonwoven geotextiles with a percent error range of 13–30%, and was used to develop simple performance charts. The developed charts can be useful for practitioners, and the developed methodology can be adopted to extend these chart solutions to other types of soils and geotextiles.