COLUMBIA, Md. — The Delaware Chapter of the American Society of Civil Engineers (ASCE) recently named Geosyntec Consultants' project, the Cherry Island Landfill Expansion in Wilmington, Del., "Outstanding Civil Engineering Project" for 2010.
The Cherry Island Landfill is located at the confluence of the Delaware and Christina Rivers. The project, which began in 2001 and is still ongoing, initially presented various challenges. One of these involved the existing landfill, which was constructed over an area partly reclaimed from the Delaware River and was used for many years as a dredged material disposal site by the U.S. Army Corps of Engineers. As a result, the subsurface characteristics at the site consist of very soft and extremely compressible materials.
Geosyntec's design approach involved a foundation improvement technique, using prefabricated vertical drains (PVDs), combined with a mechanically stabilized earth (MSE) berm. The MSE berm plays a dual role, compressing and consolidating foundation soils while providing new disposal space. The PVDs drain water from the dredged material/alluvium to an underlying sand deposit, thus allowing the dredge/alluvial soils to dissipate excess pore water pressures.
Geosyntec designed the MSE berm to be 60 feet high, almost two miles in length, and to consist of two million cubic yards of fill. When completed in late 2010, it will be one of the highest and most massive reinforced structures constructed over soft soils built in the United States. The expansion will provide 19 years of additional solid waste disposal life for Geosyntec's client, the Delaware Solid Waste Authority (DSWA).
Geosyntec provides engineering services on the Cherry Island Landfill Expansion project. The project is owned by DSWA, and the general contractor is Sevenson Environmental Services, Inc., based in Niagara Falls, N.Y.
"We are honored to be part of the team that won this award from ASCE," said Tom Ramsey, PE, Geosyntec project manager and lead designer. "The Cherry Island Landfill is one of the most challenging projects of its kind in the country, and we continue to appreciate a close working relationship with Sevenson and the DSWA as the construction nears an end."