Data on the soil beds of structures making up the Saint Petersburg flood-protection system and at test sites formed for field investigations of beds containing a thick layer of saturated clayey soils of highly plastic consistency are presented. Also cited are generalized results of multiyear measurements of strains, stresses, and pore-water pressure of the beds of the test sites during the installation of strip earth drains with subsequent loading by the layer-by-layer placement of sandy fills; these results are also analyzed.