Standards: IS 2720 (PART XVII) 1966
Specification: The constant head method is particularly suitable for relatively coarse grained soil such as sands and gravel. For fine grained soils such as clay-like or silty soils see Falling head permeability apparatus.
The apparatus consists of a Perspex permeability cell mounted on a detachable aluminium base and head. The cylinder has pressure points at different levels, which have to be connected to the manometer stand and to the constant level tank. Two models available: 75 and 114 mm cell nominal diameter.
The apparatus is used for the laboratory determination of permeability of soil using a constant or a variable head. This test is recommended for soils with co-effcient permeability in the range of 0-10-3 to 10-7 cm/sec. The maximum particle size of the soil which can be tested in the mould is 10mm. The soil permeability is a very important factor to study the behavior of soil in its natural condition with respect to water flow.