Determining the hydraulic conductivity according to DIN EN ISO 17892-11
Darcy's flow law applies to seepage flows in water-saturated soil:
vf = -kf i
kf is the hydraulic conductivity, i is the hydraulic gradient and vf is the filter speed as the average speed at which the pore water passes through a soil cross-section. kf is required to calculate the groundwater level, the seepage line in dams and dikes and the groundwater level behind structures. It provides an indication of the duration of drainage of flushing fields and is a measure of the suitability of the soil as a sealing material.
Test with constant head
The saturated soil sample is flowed through from bottom to top at a constant pressure head, and the flow is measured. Sands and cohesive soils can be examined. A back pressure can be applied. Saturation and consolidation can occur.
Test with falling head
In the test with variable pressure head, the soil sample is flowed through from bottom to top, with the pressure head, measured in a standpipe, falling over time. The test is mainly used in earthworks and landfill construction for soils with low permeability.
