Refer to Problem 3.5. Using Eq. (3.28), determine the aver- age relative density of the sand. Assume it is a fine sand. Use Eq. (3.13) to obtain (N₁)60- 3.5 Following is the variation of the field standard penetration number (No) in a sand deposit: Depth (m) 1.5 Noo 6 3. 8 4.5 9 6 8 7.9 13 14 9 The groundwater table is located at a depth of 6 m. Given: the dry unit weight of sand from 0 to a depth of 6 m is 18 kN/m², and the saturated unit weight of sand for depth 6 to 12 m is 20.2 kN/m². Use the relationship given in Eq. (3.13) to calculate the corrected penetration numbers. CN= 10.5 (3.13) Skempton (1986) suggested that, for sands with a relative density greater than 35%, (N₁)60 D 60 where (N₁)60 should be multiplied by 0.92 for coarse sands and 1.08 for fine sands. (3.28)