7. An eliptical artificial island is required for a reclamation project. The major axis of the ellipse is 10 km and the minor axis is 7.5 km (see figure). A rock breakwater, 100 m thick, forms the edges of the island. The area within the breakwater is to be filled with sand. Sand in its loosest state has a porosity of 90 percent and desired porosity, when compacted, is 20%. Assuming average thickness of the completed island is 100 m, determine the quantity of sand required. Roc

Refer to Figure 7.24. The following data were collected during the field permeability measurement of a confined aquifer using a pumping test. Determine the hydraulic conductivity of the permeable layer. Use Eq. (7.49). Thickness of the aquifer, H = 4.5 m Piezometric level and radial distance of the first observation well: h1 = 2.9 m; r1 = 17.8 m Piezometric level and radial distance of the second observation well: h2 = 1.8 m; r2 = 8.1 m Rate of discharge from pumping, q = 0.5 m3/min

A sand has Gs = 2.66. Calculate the hydraulic gradient that will cause boiling for e = 0.35, 0.45, 0.55, 0.7, and 0.8.

Refer to Figure P3.3. Use Eqs. (3.10) and (3.11) to determine the variation of OCR and preconsolidation pressure c. FIGURE P3.3