State-of-the-Art: Laboratory Hydraulic Conductivity Tests for Saturated Soils

Abstract

Hydraulic conductivity of saturated soils is measured in the laboratory with either rigid- or flexible-wall permeameters. Rigid-wall cells are preferred for granular materials, and either rigid- or flexible-wall cells are preferred for low-hydraulic conductivity materials, depending on the type of test specimen and the conditions being simulated. Procedures for selection and preparation of test specimens are critically important, even for laboratory-compacted materials. Either constant- or variable-head tests can be performed; either type of test will yield satisfactory results if used properly. For compressible materials, the head cannot change much or the test specimen will change volume. Permeation with deaired water until inflow and outflow rates equilibrate, supplemented with backpressure where appropriate, are needed to saturate test specimens. Permeation should continue until chemical equilibrium is established when testing with liquids other than water, e.g., chemical wastes.