Certain fine-grained soils with high sodium content are highly erodible by the water flowing through them. During the test the flow of water under a high hydraulic gradient through a cavity in the soil is reproduced.
Pinhole Test Apparatus is used for evaluating clay soils for erodibility by flowing water through a small hole that is drilled through the compacted specimen.
The apparatus consists of a cylindrical metal container fitted one end with a water inlet and the other end with an outlet connection, a standpipe tube with scale and a stand to support the apparatus.
