De is measured from the back (retained) ground surface down to the front (excavated / dredge) ground surface. The embedment below the front ground is (H − De).
02 · Surcharge
03 · Water Table
One water table, same physical level on both sides — with no seepage/flow-net modelled, a static level cannot differ front-to-back without flow occurring.
04 · Options
Applies to active pressure only (clay and low-surcharge sand near the top). Uncheck to see the theoretical negative pressure.
04b · EC7 Partial Factor Design (SS EN 1997-1, DA1)
Combination 1 = A1 "+" M1 "+" R1 (factor actions, keep soil strength characteristic). Combination 2 = A2 "+" M2 "+" R1 (lower action factor, but soil strength reduced). Both must be checked — the more onerous governs for a given verification (structural vs geotechnical). Front-side surcharge is treated as favourable and left unfactored, per EC7 principle. These are the standard EN 1997-1 Annex A recommended values — verify against your copy of the Singapore NA to SS EN 1997-1 for any project-specific deviation.
Moments are taken about the base of the wall (the toe, at total depth H below the back ground surface) — the classic "Simplified Fixed Earth Support" idealisation used for cantilever embedded walls (soil resistance below the rotation point is lumped into the full passive pressure diagram acting up to the wall toe). ODF = ΣMresisting (passive) / ΣMoverturning (active + surcharge + water), each about the toe. Per the EC7 single source principle, the same permanent partial factor γG,dst is applied to the soil self-weight and water components of both the active and passive diagrams (Combination 1: γG,dst=1.35; Combination 2: γG,dst=1.0) — the back surcharge keeps its own action factor (γQ or γG per the type selected in panel 04b), and front surcharge is left unfactored (favourable). γR;e = 1.0 in both combinations.