MECHANICALLY STABILIZED EARTH EMBANKMENT DESIGN AND CONSTRUCTION QUALITY ASSURANCE
Modern Landfill, Inc.
Lewiston, New York
The initial design of an optimum landfill footprint on the owner's property required demolition of an existing operating Material Recovery Facility (MRF) and relocation of high-pressure natural gas pipeline that traversed the site. After the initial design was approved, the landfill owner acquired adjacent properties, prompting redesign of the footprint to avoid demolishing the MRF and relocating the pipeline.
DE was retained to prepare the investigations, designs and application documents necessary for regulatory approval of a “Footprint Swap” that would maintain the permitted total acreage and solid waste volume. The project included an environmental impact assessment, relevant site-specific investigations and studies, and the engineering design of the reconfigured landfill.
The Right of Way for the high-pressure gas line constrained the area available to achieve the permitted landfill acreage, requiring a perimeter embankment with outside slopes ranging between 0.5H:1V and 3H:1V. For outside slopes between 2.7H:1V to 1H:1V, a geosynthetic wrapped near face open mesh bi-axial geogrid reinforced slope and a vegetated surface soil layer was specified. For slopes steeper than 1H:1V, a wire-formed, geogrid reinforced stone-faced retaining wall system was called out.
The design of the Mechanically Stabilized Earth (MSE) embankment:
Provides a stable subgrade surface for the placement of the landfills double composite liner system;
Incorporates a top of embankment roadway for construction equipment and maintenance vehicles;
Promotes surface water drainage from the landfill slopes and maintenance roadway surface to the site wide surface water management facilities;
Provides the necessary grade separation between the limit of waste and the existing ground surface along the alignment of the high pressure gas line; and,
Addresses the geotechnical requirements of the regulations governing the design and performance of landfills.
DE provided construction bid documents and provide third party Construction Quality Assurance (CQA) services during the construction of the embankment.