Question

A levee is constructed atop a 3m thick clay layer resting atop a sand layer. During a storm event, the levee retains water and the soil at the bottom of the channel is sand that is hydraulically connected to the sand beneath the clay. Head loss in the sand layer is negligible (i.e., the total head at point A is the same as the total head at point B), and water flows vertically upward through the clay. The water table is at the top of the clay layer on the left side of the levee. Compute the height of the water level, H, on the right side of the levee that would cause the vertical effective stress to be zero at the bottom of the clay. Sketch profiles of total head, pressure head, and elevation head, and of vertical total stress, pore water pressure, and vertical effective stress through the clay layer for the condition where the water level is at H on the right side of the levee and at the ground surface on the left side. A farmer owns the land on the left side of the levee, and needs to design a pump system to remove the water that flows up through the clay during the storm. His land occupies 1000 m2. How much water will the famer need to pump (m3/day) during this storm event if the water on the right side of the levee is at a height H and the water table on the left side of the levee remains at the ground surface? Levee Clay Y16 kN/m3 k10-7 m/s 3m Sand Sand 2 Total Head, Pressure Head, Elevation Head

Answer 1