(a) Cross-sections illustrating loading arrangements for Uitdam tests 1, 2, 4, 5 and 6 involving combinations of reusable concrete slabs, controlled water tank loading and (in four cases) ditches with 1 : 1 slopes whose water levels could be controlled by pumping. (b) Photograph by C. Zwanenburg of instrumented Uitdam field test, showing case with water-filled excavated ditch