The Application of Compaction and Jet Grouting for Sinkhole Remediation-Video

Video Transcription

Video Summary

In 2016, a 28-by-40-meter sinkhole, about 30 meters deep, severely disrupted Ottawa’s LRT construction, swallowing vehicles, utilities, and part of a tunnel-shaft shoring system. After the area was filled with low-strength concrete, contractors undertook remediation to stabilize disturbed ground and allow tunneling to resume.<br /><br />The work combined compaction grouting beneath the sinkhole and jet-grouted headwalls near the tunnel. Pre-drilling and hydrovac excavation helped identify obstructions and avoid utilities. Crews surveyed borehole verticality and monitored grout volumes, pressures, and installation parameters to map treatment and adjust methods. Jet-grout column diameters were checked in real time using an acoustic system.<br /><br />Because the site was confined and urban, a centrifuge separated jet-grout spoils into solids and water for disposal or reuse. The project faced complex, heterogeneous ground, buried debris, tight access, and an urgent schedule, requiring modified equipment and round-the-clock work.

Keywords

Ottawa LRT sinkhole

compaction grouting

jet grouting

ground stabilization

tunnel remediation