For H$1=10$m and H$2=8$m$,$ if time of $3$ years is desired to achieve average Uv of $90\%$ for both Clay A and Clay B$,$ what will be the additional required surcharge pressure $($p$)($in kN$/$m$2)?$

Hint; Use the formula: Total sett, $$H $=$ UA$*($mv$*$H$*\backslash$sigma v$\text{'})$clay A $+$ UB$*($mv$*$H$*\backslash$sigma v$\text{'})$clay BTwo soft clay layers A and B$,$ sandwich an intermediate sand layer. Assume ground water

level is at the ground surface.

Fig $1.$ Subsurface soil profiles, soil properties and loading conditions $($for Section B only$)$

The given design parameters are:

a$)$ Pressure of permanent fill, $p_0=60k\frac{N}{m^2}$

b$)$ Diameter of proposed sand drain, $d$ or $D_w=500mm$

c$)$ Smear factor, $f=0\mathrm{.}8$