In Situ Hydraulic Conductivity Tests for Compacted Clay

This paper summarizes the state of the art for in situ conductivity testing of compacted clay soils. Nine methods of testing are reviewed: (1) The Boutwell permeameter; (2) constant‐head borehole permeameters, e.g., the Guelph permeameter; (3) porous probes, e.g., the BAT device; (4) open, single‐ring infiltrometers; (5) open, double‐ring infiltrometers; (6) closed, single‐ring infiltrometers, (7) sealed, double‐ring infiltrometers; (8) the air‐entry permeameter; and (9) lysimeter pans. Installation procedures are given, equations for calculating hydraulic conductivity are presented, simplifying assumptions are listed, and case histories are reviewed. Each type of permeameter has advantages. The Boutwell permeameter is especially convenient for measurement of the vertical and horizontal hydraulic conductivity. Borehole permeameters and porous probes provide data relatively quickly but permeate a relatively small volume of soil. Of the permeameters that can permeate large volume of soil, the sealed double‐ring infiltrometer and pan lysimeter are the most versatile.