A falling-head permeability test was carried out on a clay soil of diameter 10 cm and length 15 cm. In 1 hour the head  in the standpipe of diameter 5 mm dropped from 68 cm to 50.2 cm. Calculate the hydraulic conductivity of this clay.

A fine sand was tested in situ to give a coefficient of permeability of 3.7 x107 m/s. A sample of the same sand, 400mm high and 100 mm in diameter was then tested in a constant head permeameter. Water percolated through the soil under a head of 600mm for 5 minutes and the discharge water had a volume of 1300mm. Determine whether the in situ testing was reflected by the laboratory results and If the below water retaining structure is 140m in width, based on a coefficient of permeability of 7.8x10°m/s, determine the quantity of water that will flow through the soil and under the structure per day.

4. A constant-head permeability test was conducted on a soil sample retained inside a cylindrical mould with a length of 40cm and an inner diameter of 18cm. In the test setup, a total of 55cm³ of water was collected during 3 hours and 15 minutes after reaching a constant-head difference of 60cm. a. Calculate the hydraulic conductivity (cm/s) of the soil sample. b. Estimate the type and permeability class of the soil. (Show all working calculations.)

7.7 In a constant-head permeability test, the length of the specimen is 200 mm and the cross sectional area is 78.5 cm². If k = 2.1 x 10-2 cm/sec, and a rate of flow of 130 cm³/min has to be maintained during the test, what should be the head difference across the specimen?