A layer of sand 6 m thick lies beneath a clay stratum 5 m thick and above abed thick shale. In order to determine the permeability of sand, a well was driven to the top of the shale and water pumped out at a rate of 0.01m3/sec. Two observation wells driven through the clay at 15m and 30 m from the pumping well and water was found to rise to levels of 3m and 2.4 m below the ground water surface. Calculate the permeability of soil.

A layer of sand 6 m thick lies beneath a clay stratum 5 m thick and above abed thick shale. In order to determine the permeability of sand, a well was driven to the top of the shale and water pumped out at a rate of 0.01m3/sec. Two observation wells driven through the clay at 15m and 30 m from the pumping well and water was found to rise to levels of 3m and 2.4 m below the ground water surface. Calculate the permeability of soil.

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN:9781305970939

Author:Braja M. Das, Khaled Sobhan

Publisher:Braja M. Das, Khaled Sobhan

Chapter9: In Situ Stresses

Section: Chapter Questions

Problem 9.12P

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A sand deposit of 12 m thick overlies a clay layer. The water table is 3 m below the ground surface. In a field permeability pump-out test, the water is pumped out at a rate of 540 liters per minute when steady state conditions are reached. Two observation wells are located at 18 m and 36 m from the Centre of the test well. The depths of the drawdown curve are 1.8 m and 1.5 m respectively for these two wells. Determine the coefficient of permeability. Include FBD.
A sand deposit of 12 m thick overlies a clay layer. The water table is 3 m below the ground surface. In a field permeability pump-out test, the water is pumped out at a rate of 540 liters per minute when steady state conditions are reached. Two observation wells are located at 18 m and 36 m from the Centre of the test well. The depths of the drawdown curve are 1.8 m and 1.5 m respectively for these two wells. Determine the coefficient of permeability. Answer must be: 4.5 × 10–1 mm/s
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