Location: Los Angeles, CA
Project Partner: Skanska USA Civil
Challenge: Installation of compaction grouting with confined access, overhead restrictions and limited work schedule.
Overview: A newly constructed embankment exhibited significant settlement. A geotechnical engineer designed a compaction grout program consisting of 198 points along each side of a railroad embankment. Each side of the embankment consisted of 100 vertical points, 49 – 15 degree angled points and 49 – 30 degree angled points for a total quantity of 396 compaction grout points to depths of 20 feet each. Additionally, work hours were initially limited to train off-hours (night work).
Results: Condon-Johnson installed a test program at night and settlements were measured during the test program. The movement was within tolerance and Condon-Johnson was allowed to change work to day shifts while the metro train was in operation. Condon-Johnson utilized a low head room TEI drill and worked off of a wood platform constructed on top with the rail ties on one side of the embankment and on a limited width bike path on the other side of the embankment. Condon-Johnson successfully drilled 8,293 LF and injected 12,135 CF of compaction grout ahead of schedule.