Large Permeameter for Continuing Erosion Filter Tests

The Continuing Erosion Filter (CEF) test and criteria were developed by Foster and Fell to assess severities of internal erosion of an existing embankment dam whose filter does not satisfy modern filter design criteria developed by Sherard and Dunnigan. Those criteria were developed from laboratory tests on materials that may not be directly applicable to the widely graded filter materials. To address this issue, a large diameter (300 mm) rigid-wall permeameter was constructed to assess the internal erosion of zoned embankment dams constructed of widely graded filter materials. The large permeameter allows for testing of embankment dam fill materials up to a maximum particle size of 37.5 mm. A commissioning test program was conducted to verify the test equipment and testing methodology used in this study. Two CEF test results from the test program are reported in this paper to demonstrate the novel features of the permeameter cell design and its test setup. These features include a split-cell design for ergonomic function, real-time outflow rate measurement, inflow and filter specimen water pressure measurements, and erosion loss measurement. A wet method to estimate erosion loss was proposed as an alternative to the traditional oven-drying method.