A layer of sand extends from ground level to a depth of 9 m and overlies a
Question:
A layer of sand extends from ground level to a depth of 9 m and overlies a layer of clay, of very low permeability, 6 m thick. The water table is 6 m below the surface of the sand. The saturated unit weight of the sand is 19 kN/m3 and that of the clay 20 kN/ m3; the unit weight of the sand above the water table is 17 kN/m3. Over a short period of time, the water table lowers by 3 mands is expected to remain permanently at this new level. Determine the effective vertical stress at depths of 8 and 12 m below ground level
(a)immediately after the lowering of the water table
b)Several years after the lowering of the water table.
Explain your answer for each part.
An Introduction to Geotechnical Engineering
ISBN: 978-0132496346
2nd edition
Authors: Robert D. Holtz, William D. Kovacs, Thomas C. Sheahan