Railroad Slope Stabilization Using Micropile A-frames-Video

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Video Summary

A railroad embankment in Virginia’s Blue Ridge Mountains had a history of movement dating back to the 1960s. In 2020, significant track deformation, leaning trees, toe bulging, and creek erosion indicated a global slope-stability problem. Geotechnical borings and slope inclinometers identified movement toward the creek along a deep failure surface.<br /><br />The project stabilized the embankment with a two-tier micropile A-frame system. The lower system used rock-socketed compression micropiles and post-tensioned tiebacks; the upper system used closely spaced, fully cased micropiles in softer soil. Construction took place beside an active railroad, requiring careful coordination and temporary shoring.<br /><br />Verification testing revealed that a contractor’s proposed pressure-grouted bond zone did not transfer loads as intended. Strain gauges helped guide an adjusted testing and acceptance approach. The project was completed successfully. Key lessons included verifying bond performance, using instrumentation to confirm load transfer and define failure surfaces, and maintaining close communication among the contractor, engineer, and railroad.

Keywords

railroad embankment

slope stability

micropile system

Virginia Blue Ridge Mountains

geotechnical instrumentation

creek erosion