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Constant head permeability test for sand

Objective of this experiment is to determine coefficient of permeability of sand by Constant head permeability test.

Description of Soil Samples:

The soil, used in the lab experiment, was coarse sand. The sand was dry, light whitish pink in color and there was no smell.

Description of Test Methodology:

Constant head permeameter, a graduated cylinder (250 cc or 500 cc), Balance- sensitive up to 0.1 g, Thermometer - sensitive up to 0.1 degree C, Rubber tubing and Stop watch were used in this experiment. At first weight of the plastic specimen tube, the porous stones, the spring, and the two rubber stoppers (W1) were taken. Then the bottom porous stone was slipped into the specimen tube, and then the bottom rubber stopper was fixed to the specimen tube. In the next step, oven-dry sand was collected in a container and the sand was poured into the specimen tube in small layers and compacted by vibration. When the length of the specimen was about two-thirds the length of the tube, the top porous stone was slipped into the tube to rest firmly on the specimen. Then a spring was placed on the top porous stone and a rubber stopper was fixed to the top of the sample tube. The weight of the assembly (W2) was determined. The length (L) of the compacted specimen in the tube was measured and the permeameter was assembled near a sink like following figure.
Water was run into the top of the large funnel fixed to the stand through a plastic tube from the water inlet. The water flowed through the specimen to the constant head chamber and to the sink through the outlet in the constant head chamber. The supply of water was adjusted to the funnel so that the water level in the funnel remained constant. At the same time, the flow was permitted to continue for about 10 minutes in order to saturate the specimen. After a steady flow was established, the water flowing out of constant head was collected and the collection time (t) was recorded with a stop watch. These were repeated thrice and average value of Q was determined. Changing the head difference, h, various value of Q were obtained. The temperature, T, was recorded.

Test Results:

Discussion:
Conclusion:
The experiment was performed safely. The experimental result matched the theoretical value of coefficient of permeability. So, this experiment was a success, as it met its objective.

Appendix:

Raw data sheet:
Falling head permeability test for sand
Purpose of this experiment is to determine coefficient of permeability of sand by Falling head permeability test.

The soil, used in the lab experiment, was clay sand i.e. fine soil. The soil was little moist, light tan in color.
Description of Test Methodology:
Falling head permeameter, Balance- sensitive up to 0.1 g, Thermometer - sensitive up to 0.1 degree C, and Stop watch were used in this experiment. At first weight of the plastic specimen tube, the porous stones, the spring, and the two rubber stoppers (W1) were taken. Then the bottom porous stone was slipped into the specimen tube, and then the bottom rubber stopper was fixed to the specimen tube. In the next step, oven-dry sand was collected in a container and the sand was poured into the specimen tube in small layers and compacted by vibration. When the length of the specimen was about two-thirds the length of the tube, the top porous stone was slipped into the tube to rest firmly on the specimen. Then a spring was placed on the top porous stone and a rubber stopper was fixed to the top of the sample tube. The weight of the assembly (W2) was determined. The length (L) of the compacted specimen in the tube was measured and the permeameter was assembled near a sink like following figure.
Water was supplied using a plastic tube from the water inlet to the burette and the water flowed from the burette to the specimen and then to the funnel. It was ensured that there was no air bubbles. Then the water was permitted to flow for some time in order to saturate the specimen. When the funnel was full, water flowed out of it into the sink. The flow of water was closed through the specimen by using the pinch cock. The volume (V) of water, drained from the burette was determined in cm3. More water was added to the burette to make another run and previous steps were repeated changing h1 and h2. Temperature, T, of water was recorded in degree Celsius.
Test Results:
Discussion:
Conclusion:
The experiment was performed safely. The experimental result did not match the theoretical value of coefficient of permeability. However, by carrying out the experiment the procedure of falling head permeability test was known. If more care would have been taken to perform the experiment, better results could have been obtained.
Appendix:
Raw data sheet: