urgency As shown in Figure $1,$ a sheet pile has been driven $5m$ into saturated sand layer to retain $7$

$m$ of backfill. The backfill consists of two layers: $4m$ of coarse sand and $3m$ of silty clay. A

surcharge pressure of $60$kPa was applied to backfill to pre$-$consolidate the silty clay layer.

The total active lateral pressure at just below $7m$ depth is: $($Assume Rankine conditions

are satisfied$)$

Figure $1$

Rankine's Active earth pressure

${}_{\frac{x}{A}}^{\text{'}}=K_9{}_2^{\text{'}}-2e^{\text{'}}\sqrt[\phantom{2}]{K_e},K_s=\frac{1-sin}{1+sin}$

Rankine's Passive earth pressure

${}_{x,}^{\text{'}}=K_r{}_z^{\text{'}}+2e^{}\sqrt[\phantom{2}]{K_t},K_{,}=\frac{1+sin{}^{\text{'}}}{1-sin{}^{\text{'}}}$

$56\mathrm{.}4k\frac{N}{m^2}$

$72\mathrm{.}9k\frac{N}{m^2}$

$68\mathrm{.}2k\frac{N}{m^2}$

$194\mathrm{.}0k\frac{N}{m^2}$