Dock-wall structural design: a dock wall treated as a gravity retaining wall must be checked against which critical actions and loading conditions?

Introduction / Context:
Dock walls act as gravity retaining structures. They must be safe for combinations of earth and water pressures and operational live loads. Comprehensive checks ensure stability against overturning, sliding, bearing failure, and structural strength.

Given Data / Assumptions:

• Dock wall retains soil when the basin is empty.
• When the basin is full and the outside is exposed, hydrostatic pressure acts inward with little counter-pressure from soil.
• Operational loads include vehicles, cranes, or rail traffic near the edge.

Concept / Approach:
Design envelopes key load cases: (1) empty dock with backfill pressure, (2) full dock with water pressure but no backfill, (3) superimposed live loads. Each governs different stability checks and reinforcement needs.

Step-by-Step Solution:
Enumerate load case 1: earth pressure outwards; check sliding/overturning.Load case 2: hydrostatic pressure inwards; ensure stability in reverse direction.Load case 3: add surcharge effects from vehicles/trains to earth pressure case.Design foundation bearing and section capacity accordingly.

Verification / Alternative check:
Codes for port structures list these as primary design cases.

Why Other Options Are Wrong:

• Each individual load case is real; omitting any could lead to unsafe design.

Common Pitfalls:

• Ignoring reversed load case when the dock is flooded after dredging outside.
• Underestimating live load proximity effects (impact factors, wheel loads).

Final Answer:
all of the above.