$($d$)$ Consider the flownet shown in Figure Q$1($d$)$ below, with a cut$-$off wall underneath the

concrete dam. The bulk unit weight of the soil is $19k\frac{N}{m^3}.$

i$.$ Estimate the coefficient of permeability of the soil if the measured flow rate $(q)$ is

$5\mathrm{.}5{10}^{-5}\frac{m^3}{s}$ per unit length.

$(2$ marks$)$

$(2$ marks$)$

ii$.$ Estimate the vertical effective stress at Point A$.$

$(3$ marks$)$

iii. Estimate the net water pressure at Point B along the cut$-$off wall.

$(2$ marks$)$

Figure Q$1($d$)$