From a flow-net diagram drawn under a concrete dam, following information are obtained: (i) The head difference between upstream and downstream side of the dam is $9 \: \mathrm{m}$. (ii) The total number of equipotential drops between upstream and downstream side of the dam is $10$. (iii) The length of the field nearest to the toe of the dam in the downstream side is $1 \: \mathrm{m}$.
If the soil below the dam is having a saturated unit weight of $21 \: \mathrm{kN} / \mathrm{m}^{3}$ and unit weight of water is $9.81 \: \mathrm{kN} / \mathrm{m}^{3}$, then the factor of safety against the quick condition will be $\_\_\_\_\_\_\_\_\_$ (round off to two decimal places).
