3) A cylindrical soil sample is connected to two water reservoirs: a) Determine the pressure, elevation, and total head at a point one meter above the bottom of the sample (point A) b) Calculate the pore pressure and effective stress at point A if the soil has a saturated unit weight of 18.7 kN/m³ c) Determine the water flow rate though the sample if the soil has a coefficient of permeability of 0.19 cm/s and the radius of the sample is 20 mm. d) Is it possible for the soil to reach the "quick condition" (zero effective stress) by raising the level of the water in the upper reservoir? Why or why not? |- 4 m 4) A new structure is planned to be constructed in an offshore location and will apply an estimated surface load of 250 kPa directly to the seafloor. The seafloor consists of a 20 m thick layer of normally consolidated marine clay which overlies an impermeable rock formation (see figure below). The clay has a saturated density of 1.9 Mg/m³ A sample of the clay layer is tested in the lab and was found to have an initial void ratio of 0.63, a compression index of Cc = 0.27, and a coefficient of consolidation of Cv = 2.1*104 cm²/s. Assume that the water level remains constant during and after loading (5m above seafloor). Water q = 250 kPa 5m 10m Clay 20m Impermeable Bedrock a) Calculate the total amount of settling that will occur due to consolidation of the clay layer b) How long will it take the clay layer to reach 50% of the total consolidation? c) Calculate the effective stress at a point in the middle of the clay layer (red circle in the plot) when the soil reaches 50% consolidation d) If the clay was actually over-consolidated (rather than normally consolidated), would the total amount of settling increase or decrease compared to your answer in a)? How do you know?
Note: (please show handwritten answers, and no AI usage !)
Provide a clear, step-by-step handwritten solution (without any detailed explanations). Ensure the work is simplified and completed manually, adhering to expert-level accuracy. Refer to the provided image for clarity and ensure all calculations are double-checked for correctness before submission. Thank you!.
Question 1:
A cylindrical soil sample is connected to two water reservoirs:
a) Determine the pressure, elevation, and total head at a point one meter above the bottom of the sample (point A).
b) Calculate the pore pressure and effective stress at point A if the soil has a saturated unit weight of 18.7kN/m^3.
c) Determine the water flow rate though the sample if the soil has a coefficient of permeability of 0.19 cm/s and the radius of the sample is 20 mm.
d) Is it possible for the soil to reach the “quick condition”(zero effective stress) by raising the level of the water in the upper reservoir? Why or why not?.
Question 2:
A new structure is planned to be constructed in an offshore location and will apply an estimated
surface load of 250 kPa directly to the seafloor. The seafloor consists of a 20 m thick layer of
normally consolidated marine clay which overlies an impermeable rock formation (see figure below). The clay has a saturated density of 1.9 Mg/m3 A sample of the clay layer is tested in the lab and was found to have an initial void ratio of 0.63, a compression index of Cc = 0.27, and a coefficient of consolidation of Cv = 2.1*10^-4 cm2/s. Assume that the water level remains constant during and after loading (5m above seafloor).
(refer to the image for clarity)
a) Calculate the total amount of settling that will occur due to consolidation of the clay layer.
b) How long will it take the clay layer to reach 50% of the total consolidation?.
c) Calculate the effective stress at a point in the middle of the clay layer (red circle in the plot)
when the soil reaches 50% consolidation.
d) If the clay was actually over-consolidated (rather than normally consolidated), would the total amount of settling increase or decrease compared to your answer in a)? How do you know?.
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