Environmental remediation projects carry a unique set of geotechnical challenges. When excavation work at the Eatonville Landfill in Pierce County, Washington required stabilization of the east flank of the excavation, GeoStabilization International was called upon to deliver a permanent engineered solution in a sensitive and demanding environment.
The east flank of the Eatonville Landfill excavation presented significant stability concerns. The combination of landfill materials, excavation-induced stress, and the seismically active Pacific Northwest environment required a system designed to perform under both static and dynamic loading conditions. With active remediation work underway nearby, construction sequencing and safety were paramount.
GSI designed and constructed a 156-foot-long permanent soil nail wall reaching a maximum height of 30 feet. The system featured 2,429 square feet of reinforced and sculpted shotcrete facing — providing both structural performance and a finished aesthetic appropriate for the project context. Up to five rows of hollow bar soil nails were installed to depths of 55 feet and secured with welded wire mesh, waler bars, and bearing plates. Construction was staged in carefully controlled 5-foot lifts at 2H:1V benches, with verification and proof testing conducted throughout each phase. The design followed FHWA GEC 007 standards, achieving factors of safety of 1.3 for static conditions and 1.0 for seismic conditions.
The completed wall successfully stabilized the excavation flank, allowing the broader environmental remediation program at the Eatonville Landfill to proceed safely. By integrating seismic performance criteria and rigorous testing protocols into the design-build process, GeoStabilization delivered a solution that will protect the site for decades to come.
