Heavy Reinforcements: Stabilizing and Supporting a Stone Embankment with a Geogrid Reinforced Stone Load Transfer Platform-Video

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Video Summary

The presentation covered stabilization of the MBTA’s Charlestown bus facility shoreline along the Mystic River. A failing seawall, corroded drainage pipes, and soil loss threatened the facility’s roadway. Design was constrained by very weak river sediments, nearby buildings and piles, and critical 345-kV power lines that could not be disturbed.<br /><br />The solution used an earthen embankment to buttress the seawall, armored with riprap below the high-water mark and bioengineered treatments above. Jet-grout columns transferred loads through weak soils, while layered geogrid formed a load-transfer platform. Gabion baskets provided anchorage for the geogrid in the one-sided embankment. Construction required careful sequencing, water treatment, and protection of the river.<br /><br />Settlement plates, tubes, and inclinometers monitored performance. Reusing jet-grout spoils as a working platform effectively preloaded the organic soils, reducing later settlement. Key lessons included planning for construction tolerances, anchorage, and potential geogrid damage, with adequate design safety margins.

Keywords

MBTA Charlestown bus facility

Mystic River shoreline stabilization

seawall repair

jet-grout columns

geogrid load-transfer platform

riprap embankment