Hydraulic permeability of structures made of geotextile sand containers: Laboratory tests and conceptual model

The permeability values were obtained for more than 15 different geotextile sand container (GSCs)-structures. The influence of the size of the sand containers (four different sizes were tested), arrangement and geometry was investigated. First results show that the size of the container represents one of the primary factors influencing the permeability but the method of placement of the GSCs also plays a significant role (different methods of placing resulted in a permeability with more than a 50% difference). The results show that the flow through the GSC-structure is solely governed by the gaps between neighbouring containers and that the flow through the sand fill in the containers can be neglected.In addition, several GSC-structures with the same geometry and the same size of containers but with different arrangements (and thus different permeabilities) were tested under wave action in the twin wave flume of LWI. The results show that the mode of placement of elements strongly affects the permeability and the stability of GSC-structures. Placement of the containers in such a way that the contact areas among containers are maximized resulted in the largest overall stability against wave action. A conceptual model for the determination of the permeability of GSC-structures is proposed.