The flow net around a sheet pile wall is shown in the sketch. The properties of the soil are: permeability coefficient $0.09 \: m/day$ (isotropic), specific gravity $=2.70$ and void ratio $=0.85$. The sheet pile wall and the bottom of the soil are impermeable.
The factor of safety against the occurrence of piping failure is
- $3.55$
- $2.93$
- $2.60$
- $0.39$