Answer Happy

8 -2 A sandy soil has a isotropic permeability of k = 2.5 . 107 m/s, and is situated on top of an impermeable layer (located at z = 0 m, see figure below). Sheet pile walls "A" and "B" are installed to a level of z=10 m above the bedrock to construct a 10 m wide excavation. Between these sheet piles, soil is excavated to a level of z=12 m above the bedrock. Water has to be continuously pumped out of the excavation to ensure the excavation remains dry (i.e. water table at ground surface level in the excavation). The water table on the left-hand side and right-hand side of the excavation are located at z=20 and z=25 m above the level of the bedrock, respectively. The soil surfaces are located at z=15 m (left-hand side) and z=20 m (right-hand side). A flow net for an excavation problem is drawn, see figure below. B 25- А. 20 15 VN z [m] 10- 5- 0 0 10 - 30 40 20 x [m]
a) Estimate both the horizontal and vertical flow rate (in m/s) at a point located just to the right of sheet pile wall "B" and just underneath the soil surface (6 points) Enter your workings here (you are allowed to use letters for symbols, e.g. "k" for permeability, "qx" and "qz" for flow rates in horizontal and vertical directions etc.) Enter value for the horizontal flow rate: m/s Enter value for the vertical flow rate: m/s b) Calculate the minimum amount of water that has to be extracted to ensure the excavation remains dry (8 points). Enter your workings here (you are allowed to use letters for symbols, e.g. "k" for permeability, "Nf" for number of flow channels etc.) Enter value for amount of water that needs to be extracted: m3/s/m c) Calculate the pore pressure immediately underneath sheet pile wall "B". Assume the unit weight of water is 10 kN/m3 (6 points). Enter your workings here (you are allowed to use letters for symbols, e.g. "h" for hydraulic head, "u" for pore pressure etc.) | Σ + Add row Duplicate row E Enter value for the pore pressure: KP