Corps Invents Filter That Helps Sand Boils Plug Themselves

Two researchers with the Corps of Engineers have been granted a patent for a filter that helps sand boils plug themselves.

The patent application credits Isaac Stephens and Bryant Robbins with the invention. Both are research civil engineers with the Corps’ Engineer Research and Development Center. Stephens’ specialty is soil mechanics, seepage and erosion and site characterization and instrumentation. Robbins specializes in “geotechnical, hydraulic, and structural aspects of water resources infrastructure,” according to his Linkedin page.  His primary focus over the past few years has been research related to geotechnical failure modes for dams and levees.

A sand boil is “an eruption of a liquefaction of sediment (e.g., sand and water) through a bed of sediment due, for instance, to differences in water pressure on two sides of a levee” according to the application. Sand boils can require enormous amounts of labor to combat manually, usually by surrounding the boil with a ring of sandbags.

The application was filed in March 2018 and published by the U.S. Patent Office on September 5, 2019. It describes and illustrates a conical mesh filter that looks something like an upside-down furled mesh umbrella. Inserted and opened underground in the boil, again like an umbrella, it traps inrushing soil, gravel and sediment that forms a plug, while allowing water to flow through the mesh.