Hanging bag test

The performance of the selected fabric with respect to its infill and site-specific conditions can be assessed or predicted on the basis of simulated large-scale testing. Insofar as testing is concerned there are several options, but two seem to be most common. They are the hanging bag test and the pillow test. Both are standardized and the subject of a published article see Koemer and Koemer (2009), from which the following is taken. 

The hanging bag test was originated by Jack Fowler of the US Army Corps of Engineers in the mid-1990s (Fowler, 1995). It was eventually formalized as a standard in 2004 (GRTGT14). There have been several articles written about the test, which are generally favorable insofar as fabric selection is concerned (Zofchak, 2001 Bezuijen et al., 2007 Koemer and Koerner, 2006 Liao and Bhatia, 2006). 

The pillow test per GRI-GT15 uses the candidate fabric prefabricated into the shape of a pillow from which a flanged connector and a calibrated vertical standpipe are attached. The fabric enclosure is small and the amount of slurry needed per test is much less than with the hanging bag test. More important, the hydraulic head (converted to inlet pressure) can be monitored over time, resulting in a quantitative assessment of the system including the specific effects of the fabric, slurry, and its additives. A pillow test in progress is shown in Fig. 21.3. 

GRI-GT14, 2004. Standard Test Method for Hanging Bag Test for Field Assessment of Fabrics Used for Geotextile Tubes and Containers. Geosynthetic Institute, Folsom, Pennsylvania, USA. 

Koerner, G.R., Koemer, R.M., 2006. Geotextile tube assessment using a hanging bag test. Journal of Geotextiles and Geomembranes 24 (2), 129—137. 

Liao, K., Bhatia, S., 2006. Evaluation on filtration performance of woven geotextiles by falling head, pressure filtration, and hanging bag tests. In Proceedings 8th IGC, Yokohama, Japan. Millpress PubL, Rotterdam. 

---