Constant head permeability - Lab Report Example

Permeability as defined above is the capacity of sample of soil to allow the passage of water through it. It is also referred to as hydraulic conductivity. The coefficient of permeability is the velocity of flow that is generated by the hydraulic gradient of unity as stipulated by Darcy’s law which is given by the formula: 6. The tamping device is then used to compact the soil layer. About 10 rams per layer are recommended in order to provide a uniform coverage of the surface of the soil. The process should be repeated until the soil layer is within the range of 2 cm. 10. The bottom of the outlet valve is opened and raised to a given height in order to achieve a reasonable steady flow of water.

Enough time should be allowed for the pattern of flow of the water to stabilize. 11. The time taken to fill a volume of 750-1000 ml using the graduated cylinder and the temperatures of the water recorded. This process is repeated three times and the average time, volume and average temperature computed. From the foregoing, it is clear that the value of the coefficient of permeability has been determined using the constant head test and found to be 0.2333 cm/s. as indicated earlier that the constant head test is appropriate for permeability’s of soils where k>10 – 4 cm/s, this has been proven to be consistent with the results obtained.

Constant Head Permeability Test in Sand, University of Texas at Arlington Geotechnical Engineering Laboratory Test Procedure. Retrieved from: http://www.uta.edu/ce/geotech/lab/Main/Soil%20Lab/08_Permeability/permeability_lecture%20note.pdf. Accessed on 15th April