Permeability Apparatus

Description

Standard: IS 2720 (PART-XV), IS:12287, BS:1377, ASTM D2435

Permeability is a property of soil which permits flow of water through its interconnecting voids. Permeability is an important engineering property which governs the rate of settlement of saturated compressible soil layers and the rate of flow of aquifer. Permeability is taken into account for pumping ground water, spacing well points for de-watering foundation sites for excavation, retention of water in reservoirs, design of dams and selection of soils to be used for various zones of embankments of dams and reservoirs.

Coefficient of permeability can be computed from effective diameter of particles, porosity, specific surface and from consolidation test results. But permeability depends on numerous factors; hence, determination of permeability by direct laboratory method using an apparatus called Permeameter is considered more accurate. Specimen used in a permeameter is small, time taken is less and results obtained are accurate.

There are two types of Permeameters, namely Constant Head Permeameter and Falling Head Permeameter. Falling Head Permeameters are used for testing remolded or undisturbed fine-grained soil having less than 10·2 cm/sec coefficient of permeability and Constant Head Permeameters are used for coarse grained cohesion less soils.

The Equipment consist of the following replaceable parts:

VS 24201   Stand with Three Glass Tubes of 6mm, 10mm, and 20mm dia Approx.

VS 24202   Metallic Mould 100mm dia X 127.3mm Height, 1000ml Volume.

VS 24203   Extension collar 100mm dia X 60mm Height.

VS 24204   Drainage Base Plate with a Recess for porous Stone and an Outlet valve.