Design, Installation and Performance of Earth Retention System to Limit Ground Movements Around Sensitive Structures in Washington, DC-Video

Video Transcription

Video Summary

The presentation described a temporary earth-retention and micropile project behind Washington, D.C.’s historic House of the Temple. The site’s urban fill and dense Potomac Formation soils contained cemented sands, gravels, cobbles, and boulders, complicating pile and tieback installation. Excavations reached about 40 feet, with nearby sensitive structures including the Temple, a carriage house, and a townhouse.<br /><br />The team designed a stiff soldier-pile-and-tieback system, adding tieback levels near adjacent buildings and carefully controlling vibration and ground loss. Extensive monitoring and coordination helped protect the structures. Cemented sands initially prevented piles from reaching depth; after groundwater softened the layers, installation succeeded. The team later installed 28 permanent micropiles using casing, regrouting, and a preliminary bond test.<br /><br />The system performed well: wall settlement was under a quarter inch, adjacent movement was negligible, and no structural damage occurred. The micropiles were successfully installed in the dense soils and became permanent foundation elements.

Keywords

earth-retention

micropiles

soldier-pile-and-tieback

Potomac Formation soils

groundwater monitoring