Constructing a Landfill in a Former CCR Basin

Kory Anstead, AECOM

Description

Design and Construction Challenges with Construction of a Landfill in a Former CCR Basin Authors Mr. Kory Anstead - United States - AECOM Abstract Utilizing best engineering practices and discussing lessons learned associated with challenges encountered during construction of a landfill for CCR materials in a former CCR basin. Challenges encountered included higher than anticipated groundwater conditions, presence of rock at higher elevations, not feasible to construct one of the sediment basins due to ash excavation sequence, softer subgrade conditions, and storm water management. These challenges were mainly the result of limitations in access to investigate future landfill area located inside the CCR basin. These challenges impacted ongoing construction. Mitigation included re-design of a leachate basin and associated lessons learned involving investigation activities and early indicators in construction. Design of an underdrain system was added during construction. Discussion of lessons learned associated with the engineering design and knowledge of how the schedule impacts of this could be avoided in the future. Discussions of general saturated soil management throughout construction as well as specific encounters with the final stages of base construction involving lime/cement mixture to help stabilize subgrade soils. This presentation addresses several specific construction-related aspects based on the above challenges described as well as the lessons learned. The presentation will also discuss general construction considerations involving the rock surface encountered in unexpected areas and mitigation with engineering considerations and approaches. The presentation will also discuss engineering considerations for stages of the spillway modifications between the two units and management of the regulatory requirements involved. This presentation addresses several specific construction-related aspects based on the above challenges described as well as the lessons learned.

 
May 14th, 11:00 AM May 14th, 11:30 AM

Constructing a Landfill in a Former CCR Basin

Grand Rapids, Michigan

Design and Construction Challenges with Construction of a Landfill in a Former CCR Basin Authors Mr. Kory Anstead - United States - AECOM Abstract Utilizing best engineering practices and discussing lessons learned associated with challenges encountered during construction of a landfill for CCR materials in a former CCR basin. Challenges encountered included higher than anticipated groundwater conditions, presence of rock at higher elevations, not feasible to construct one of the sediment basins due to ash excavation sequence, softer subgrade conditions, and storm water management. These challenges were mainly the result of limitations in access to investigate future landfill area located inside the CCR basin. These challenges impacted ongoing construction. Mitigation included re-design of a leachate basin and associated lessons learned involving investigation activities and early indicators in construction. Design of an underdrain system was added during construction. Discussion of lessons learned associated with the engineering design and knowledge of how the schedule impacts of this could be avoided in the future. Discussions of general saturated soil management throughout construction as well as specific encounters with the final stages of base construction involving lime/cement mixture to help stabilize subgrade soils. This presentation addresses several specific construction-related aspects based on the above challenges described as well as the lessons learned. The presentation will also discuss general construction considerations involving the rock surface encountered in unexpected areas and mitigation with engineering considerations and approaches. The presentation will also discuss engineering considerations for stages of the spillway modifications between the two units and management of the regulatory requirements involved. This presentation addresses several specific construction-related aspects based on the above challenges described as well as the lessons learned.