Lateral pressure on the trench wall against depth (kPa): effective soil pressure, net water pressure and the design envelope with its minimum equivalent-fluid top-up; yellow verticals = strut levels
Factor of safety of the planar failure wedge against its angle (right wall, left wall). Dip below 1 = failure possible
Minimum factor of safety of an unsupported cut against trench depth at the current soil, water and surcharge
Groundwater table across the trench section (Dupuit drawdown to the ditch and the pumped trench)
Log roof utilisation (largest of bending stress and long-term deflection) against earth-cover thickness, for three log diameters