Problem $4(3\mathrm{.}0$ pts$)$

Given a strip of surcharge loading $($infinite extension along out$-$of$-$plane direction$)$

The unit weight of fill sand is $18k\frac{N}{m^3}.$ Determine the increased vertical stress at points A and B $.$

Note: the slope $1$:$1\mathrm{.}5$ means that $tan()=\frac{1}{1\mathrm{.}5}$

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