Slope Stability

PART $1$: Vibroflotation is a ground improvement technique that is used to densify in situ thick layers of loose granular soil deposits. The vibroflot is lower by a crane into the soil and a water jet at the bottom of the vibroflot quickens the soil and allows the vibroflot to sink and create a hole in the ground. Backfill material is poured into the hole and the water jets in the vibroflot carry the backfill down the hole. The vibroflot is slowly raised and vibrates in lifts until the backfill is at the desired unit weight. A diagram of the vibroflotation process is shown in the following figure.

Vibroflotation Process $($Source: OMS Pile Driving Equipment$)$

The suitability number, $S_N,$ is a quantity used to rate a backfill for use in vibroflotation and is as follows:

$S_N=1\mathrm{.}7\sqrt[\phantom{2}]{\frac{3}{(D_{50}{)}^2}+\frac{1}{(D_{20}{)}^2}+\frac{1}{(D_{10}{)}^2}}$

$2$