Project:
Nu-Way, Live Oak, and Arrow Pits – Inert Debris Fills – Geotechnical Investigations and Design of Engineered Fill Cap Using FLAC Analyses
Overview
The City of Irwindale has multiple gravel pits that were mined for construction materials resources to depths of up to 150 feet and had been backfilled with inert construction debris fills containing oversize materials up to 5 to 10 feet in maximum size. Development of these inert debris fill sites to commercial/industrial development projects presented economic challenges for the pit owners/developers as they will require complete removals of these materials and backfilling with controlled compacted fills to meet the static and seismic settlement criteria of governing agency, Los Angeles County Public Works.
Location:
Irwindale, California
Owner / Client:
Confidential
Performance Period:
2012-2021
Services:
- Solid Waste Engineering
- Permitting and Regulatory Compliance
- Post-Closure Land Use and Development
Scope of Services Provided by AES
AES performed geotechnical services and FLAC modeling for three inert debris landfills backfilled with construction and demolition debris to depths of 150 feet. The field and laboratory investigations and modeling included:
- Geotechnical investigation and characterization of existing fill materials, involving 80-foot-deep test excavation and large-scale in situ density and grain size distribution testing; hydrocollapse tests on specially fabricated laboratory equipment to test oversize materials; geotechnical laboratory testing of finer portions fills; and construction of test pads and large-scale density testing to determine maximum achievable density.
- Evaluation of debris fill properties from the results of field and laboratory tests.
- Estimate of settlement potential under seismic shaking and hydrocollapse.
- FLAC modeling to design compacted fill cap to mitigate surface manifestation of differential settlement of inert debris fill left in place below the compacted fill cap. The differential settlements had to meet LA County Grading Code requirements of 1 inch in 30 feet.
- Permitting the site for commercial development per LA County Public Works guidelines.
Accomplishments / Commendations
AES’ state-of-the-art geotechnical investigation techniques and advanced software tools converted substandard inert debris fill sites info successful high-value industrial projects meeting agency approvals and providing huge savings for developers/pit owners.
AES published a technical paper by Suji Somasundaram, Kris Khilnani, T. Shenthan, and Jamie Irvine, “Characterization and Settlement Modeling of Deep Inert Debris Fills,” which was presented at the 18th International Conference on Soil Mechanics and Geotechnical Engineering in Paris in 2013.