Reinforced Soil structure for landfills
|Owner||APAC- Southeast Atlanta, GA|
|Site Consulting Engineer||Hodges, Harbin Newberry & Tribble,Inc.|
|Reinforced Structure Design||Schnabel Engineering Westchester, PA|
|Contractor||APAC Construction Atlanta, GA|
|Geogrid Type||StrataGridTM SG500 and SG550|
|Slope Geometry||Max. Height: 40 Feet, Max. Height: 40 Feet, Steep Slope|
The Donzi Lane Landfill in Atlanta, GA had been in use since the 1970's for construction and demolition waste disposal. The site was nearing its capacity and additional landfill space was urgently needed due to the accelerating population growth and waste stream generated by development. The owners of the Donzi Lane Landfill wanted an innovative way to expand the existing capacity of the landfill.
Since the lateral expansion was not possible, Strata recommended vertical expansion with a steepened slope. However, vertical expansion created an added complication.
High Tension Line Relocation - The existing high tension lines were mounted on transmission supports that traversed the center of the landfill. Height limitations were so severe that dump trucks could no longer lift their beds to discharge waste without interfering with power lines. The lines had to be relocated and raised to allow dump trucks to traverse the site. This was a critical-path activity due to the new power line foundation supports being located within the reinforced fill. The black bands on the power lines shown in Figure 3 indicate the maximum slope height.
Strata's Innovative Solution
After critical analysis of the site, Strata’s technical team of civil engineers designed an innovative and the most appropriate solution- the StrataSlope System (geogrid-reinforced steep slopes with wire-basket facing). This was the safest and highly engineered method of expanding the tightly- restricted landfill.
Vertical expansion Geotechnical design – An increase in usable landfill volume can be achieved when side slopes are steepened with geosynthetic reinforcement. A complete geotechnical analysis of the site structures, Stability analysis (that includes internal stability, compound stability, direct sliding, and Seismic stability analysis) was performed and 0.5H:1V (63º) reinforced steep slope with rock filled wire basket facing was advised. The planned finished height of the structures reached 40 feet.
The primary reinforcement layers consisted of StrataGridTM SG500 and SG550 with maximum embedment lengths of 26 feet. Vertical spacing of the primary reinforcement varied. The vertical spacing for the initial 6 feet of slope construction was 1.5 feet, while 3 feet vertical spacing was utilized for the remainder of the slope up to the maximum vertical height of 40 feet. The facing detail utilized StrataGridTM SG150 for secondary reinforcement and 90-degree welded wire baskets for facing support.
Strata's Value Addition
- Increased the total dumping capacity by 3 million cubic yards (~ 2.29 million cubic meters)
- Safe and robust to withstand differential settlements without distress
- Rapid construction with technically sound systems
- Long term erosion control and minimal maintenance due to the innovative technologies used
- Cost-effective by providing more storage revenue within the same land space