$($b$)$ Calculate the water level required for the slope on Figure Q$4\mathrm{.}1$ to fail. The data

required for the calculations is in the figure.

Clay Soil: $,=19\mathrm{.}7k\frac{N}{m^3}$

${}^{\text{'}}=24$

$c^{\text{'}}=10$kPa

Figure $Q4\mathrm{.}1$