Method and device for a foundation by depression in an aquatic site

Claim 1

In an underwater foundation structure for controlled submerged depression in an aquatic site, including: a tank having an apron forming the bottom of said structure with a ridge projecting downwardly therefrom and digging into the ground, which ground comprises at least two stratified layers in the form of a surface layer of permeable sand resting on an impermeable layer of clay, the improvement comprising: said ridge having a height greater than the thickness of said sandy layer and extending continuously about the periphery of said apron to enclose the sandy layer within a confined space between said apron, the ridge and said clay layer after initial submergence of said tank, tubular funnels extending vertically through the tank from said apron to the top of said tank with said funnels being provided with closures at their upper ends to permit the removal of water trapped beneath said apron during initial submergence of said foundation structure, tubular drains extending through the tank and having their lower ends entering the sand layer and their upper ends projecting above the surface of the water of the aquatic site, filters provided at the lower ends of said drains where the drains enter the sandy layer to insure the removal of water, and pumps housed internally of the drains for pumping water through the drains to create said depression and for expelling water from the upper ends of the drains captured within the layer of permeable sand above the surface of said aquatic site.