Monitoring Preload Performance

Reconstruction of State Highway 29 (STH 29) in north central Wisconsin was complicated by two separate deposits of compressible peat and organic silt within the highway right-of-way. The deposits ranged from about 3 to 11 meters in thickness over about 900 meters of the reconstruction alignment. Excavation and removal of the peat and organic silt was evaluated, but was determined to be cost prohibitive. Preloading was determined to be a cost effective and environmentally friendly solution, and was implemented at both deposits to induce the expected consolidation and long-term secondary compression of the final highway embankment and pavement sections. This paper presents the design, instrumentation, and rheological modeling procedures used to complete the project.