GTA provided geotechnical explorations, laboratory testing, geotechnical evaluations and reports, environmental consulting, and construction observation and testing services (COTS) for this 100-acre, 1.2 million-SF residential, retail, and commercial development, located at the site of a former sand and gravel mine reclaimed with fly ash. Site issues encountered included: fly ash fill, loose fly ash, uncontrolled fill, a stump dump (methane), a deep mined hole, a tall retaining wall on uncontrolled fill, an existing deep sewer with poor backfill, and a proposed deep sewer close to a building.
GTA researched and developed recommendations for low permeability asphalt pavement to provide a permeability of 10-7 cm/sec or less. GTA also performed test strips, obtained core samples, and performed laboratory testing to verify mix design and assess constructability of the asphalt pavement. Low permeability concrete was also used at the site. The new site development forms an impermeable cap to reduce surface water infiltration into underlying fly ash fill.
GTA’s COTS included monitoring of earthwork (portions of which were performed within fly ash fills) including construction of stormwater management facilities, mass grading, and underground utilities. Also responsible for observation of construction of a low permeability cap including clay soils, low permeability asphalt and concrete, and construction of foundations, structural steel framing, and masonry.