Question $6$

$(18\%)$

To what height can coal be piled vertically over $4m4m$ area in a coal storage

yard, so that the safety of a $450mm$ diameter vitrified clay extra$-$strength sewer pipe

placed in a Class B bedding $($Load factor $=1\mathrm{.}9)$ is not threatened? Use Martson's

Formula.

Given:

o Trench width $=0\mathrm{.}90m.$

o Depth from ground level to sewer crown is $2\mathrm{.}0m.$

Backfill soil is damp saturated clay.

Specific weight of coal is $16,000\frac{N}{m^3}.$

Thickness of sewer pipe is $40mm.$

o Three$-$edge bearing strength of the pipe $=48,100\frac{N}{m}.$