Role of geotextiles pore size distribution in dewatering tests

For geotextile tube dewatering applications, several researchers have used one-dimensional dewatering tests to estimate soil piping and sediment retention by correlating geotextile pore openings (AOS, O50-O98) and sediment particle size (D10-D90). These results are of limited use in predicting the dewatering rate required to meet a specific standard in a full-scale geotextile tube application since, in the field, flow rate is more important than sediment piping or retention. To overcome some of the limitations, this study focused on evaluating the role of geotextile pore size distribution on flow rate using the pressurized two-dimensional dewatering test (P2DT) with unconditioned and conditioned slurries. In this test, the radial and axial flow can be measured independently, therefore enabling accurate assessment of the performance of geotextile tubes under actual full-scale field conditions. In this study, glacial rock dust was used as sediment, and 1-woven, 2-composite, 2-nonwoven and 1-natural nonwoven geotextiles were used in the dewatering tests. Twelve P2DT and 40 capillary flow tests were performed to evaluate the dewatering characteristics of geotextiles. The test results showed that the pore size distribution of geotextiles played a role in effluent release with conditioned slurries.