Dynamic Compaction: A Proven Ground Improvement Method for Landfill Sites

During the past 40 years, ground improvement has become a valuable tool for the geotechnical community, as the number of sites with suitable bearing soils becomes fewer and farther between. Similarly, as time moves on, more sites come into focus for development that have received any number of various landfill materials, be it municipal solid waste (MSW) from households, construction and demolition (C&D) debris from construction activities, or simply soil materials exported from another site. As a result, the challenges to engineers and contractors to design and construct new developments within budget and on time continue to increase. Dynamic compaction is a ground improvement technique that has been used more frequently to improve in-place landfill materials to a point where vertical construction can proceed without excessive long-term settlements. On sites where dynamic compaction is used, alternative methods of post-improvement evaluation have become more common, given the number of below-grade obstructions at a site that typically prohibit standard drilling approaches. Embankment load testing, plate load testing, and where applicable, post-improvement drilling are all techniques that have been used successfully to evaluate the effectiveness of dynamic compaction programs, as outlined by the three case studies discussed herein.