Permeability

Constant Head Test

  1. Add a permeameter from the apparatus menu.
  2. Add a soil sample from the apparatus menu. The sample is directly added to the permeameter mould. It is assumed that the soil has been mixed with a sufficient quantity of distilled water to prevent the segregation of particle sizes during placement into the permeameter. Enough water should be added so that the mixture may flow freely. Also, the soil is compacted using a tamping device. Finally, the soil dimensions are measured as is visible from the values in the observations menu.
  3. Add filters from the apparatus menu to the top and bottom of the permeameter. Each of the filters has an attached pipe for inflow/outflow of liquid.
  4. Add a water supply from the apparatus menu to the top filter's pipe. This consists of a filled reservoir and a tap. The tap is to maintain a constant head at the input/reservoir.
  5. Add a container from the apparatus menu to collect the outgoing liquid (water). The container has markings to help determine the quantity of water collected.
  6. Allow water to flow through the permeameter (and hence the soil) by clicking on the reservoir. Observe the change in the water heads at the two manometers. Note that before the main procedure (water flow), some water is allowed to pass through to saturate the sample.
  7. The water flows at a steady rate. Various values such as the time taken, quantity of water, and the constant head are recorded as is visible from the table. The procedure is repeated for different head values. Finally, the permeability is computed for each of the different trials using the formula mentioned in the theory.
  8. Click the restart button to perform the experiment again.

Variable Head Test

  1. Add a mould from the apparatus menu.
  2. Add a soil sample from the apparatus menu. The sample is directly added to the permeameter mould. It is assumed that the soil has been mixed with a sufficient quantity of distilled water to prevent the segregation of particle sizes during placement into the permeameter. Enough water should be added so that the mixture may flow freely. Also, the soil is compacted using a tamping device. Finally, the soil dimensions are measured as is visible from the values in the observations menu.
  3. Add filters from the apparatus menu to the top and bottom of the mould. Each of the filters has an attached pipe for inflow/outflow of liquid. Additionally, the top filter pipe has an attached stand pipe used for the measurement of change in the water head and its cross-sectional area is determined as is visible from the value in the observations menu.
  4. Add water from the apparatus menu to the top filter's stand pipe.
  5. Add a filled tank from the apparatus menu. The mould is placed inside the tank.
  6. Add a container from the apparatus menu to collect the outgoing liquid (water). The container has markings to help determine the quantity of water collected.
  7. Allow water to flow through the mould (and hence the soil) by clicking on the mould. Observe the change in the water head in the stand pipe.
  8. The water flows at a steady rate. Various values such as the time taken, starting head, and the final head are recorded as is visible from the table. The procedure is repeated for different starting head values. Finally, the permeability is computed for each of the different trials using the formula mentioned in the theory.
  9. Click the restart button to perform the experiment again.