Q$2.$ A continuous foundation $)$ is to be constructed on a weak soft soil layer $(C_u=32$kPa,${}_2=18k\frac{N}{m}3)$ to support a load of $300k\frac{N}{m}$ with a FS of $3($Figure $4).$ However, due to the low load bearing capacity of the foundation soil, it has been determined to use a granular trench $(\frac{O}{1^{\text{'}}}=30)$ under the foundation. Determine the minimum width and estimate the required depth of the granular trench using an excel sheet. $($Hint: Use Madhav and Vitkar's bearing$-$capacity factors curves for $N_{c(T)},N_{q(T)}$ and $N_{q(T)}.$

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