8. Water flows through the constant head setup in the laboratory, as shown in the figure, where two identical dense sand samples A and B are placed-one horizontally and the other vertically. The samples are 50 mm diameter and 100 mm in length. The water lev- els in the left and right sides are maintained at the levels shown, ensuring constant head throughout the test. The void ratio of the sand is 0.92 and the specific gravity of the grains is 2.69. If 165 g of water was collected in the bucket within 15 minutes, what is the perme- ability of the soil? What are the pore water pressure and vertical effective stress at the mid height of sample B? 100 mm Answer 0.98 X 10 cm/s; 1349 Pa, 78 Pa 190 mm 40 mm 100 mm