Cutoff Walls for Groundwater Containment and Corrective Action.pdf

Dale Evans, RECON
Paul Schmall, Keller
Jeff Bean, Keller

Description

Cutoff Walls for Groundwater Containment and Corrective Action Authors Mr. Dale Evans - United States - RECON Dr. Paul Schmall - United States - Keller Mr. Jeff Bean - United States - Keller Abstract With years of pond closure work already completed, there is a recent shift of focus that has been drawing significant attention to perimeter groundwater barriers for corrective action or for containing deep saturated ash below historic groundwater levels. The implementation of perimeter cut-offs is particularly challenging for CCR ponds because of the lack of space outside of these sites, the sensitive environment in which this work is occurring, and in some cases the need for these cut-off walls to be installed through ash. The available techniques (that the authors have extensive experience with) are conventional slurry trenches, deep soil mixing with either single or multiple axis equipment (DMM), the TRD method of “chain saw” soil mixing, Cutter Soil Mixing (CSM), slurry diaphragm walls, and jet grouting. Each of these methods have advantages and disadvantages with accessibility of equipment, penetrability of the method through ash, difficult ground and rock, and cost. This paper will discuss the pros and cons of each of the barrier wall methods and examples of perimeter cutoff walls implemented on CCR projects and other environmental containment projects.

 
May 15th, 11:00 AM May 15th, 11:30 AM

Cutoff Walls for Groundwater Containment and Corrective Action.pdf

Grand Rapids, Michigan

Cutoff Walls for Groundwater Containment and Corrective Action Authors Mr. Dale Evans - United States - RECON Dr. Paul Schmall - United States - Keller Mr. Jeff Bean - United States - Keller Abstract With years of pond closure work already completed, there is a recent shift of focus that has been drawing significant attention to perimeter groundwater barriers for corrective action or for containing deep saturated ash below historic groundwater levels. The implementation of perimeter cut-offs is particularly challenging for CCR ponds because of the lack of space outside of these sites, the sensitive environment in which this work is occurring, and in some cases the need for these cut-off walls to be installed through ash. The available techniques (that the authors have extensive experience with) are conventional slurry trenches, deep soil mixing with either single or multiple axis equipment (DMM), the TRD method of “chain saw” soil mixing, Cutter Soil Mixing (CSM), slurry diaphragm walls, and jet grouting. Each of these methods have advantages and disadvantages with accessibility of equipment, penetrability of the method through ash, difficult ground and rock, and cost. This paper will discuss the pros and cons of each of the barrier wall methods and examples of perimeter cutoff walls implemented on CCR projects and other environmental containment projects.