Settlement Mitigation of Large Manufacturing Operation Using Low Mobility Grout-Paper

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A 31,500-square-foot manufacturing facility in Golden, Colorado, was built over landfill material extending to bedrock. Settlement became evident in 2010, raising concerns about structural performance and methane intrusion from the landfill.<br /><br />The owner evaluated micropiles and low-mobility grouting (LMG). Micropiles offered rigid support but required large openings through the floor and methane barrier, creating construction and operational risks. LMG required only small penetrations, was less disruptive and less costly, but its effectiveness in the site’s variable landfill conditions was uncertain.<br /><br />In 2015, LMG was trialed beneath eight heavily loaded center columns. Thirty injection points were installed, placing 84.4 cubic yards of grout. Monitoring showed settlement slowed from nearly 2 inches per year before treatment to about 0.34 inches per year afterward. Based on these results, LMG was extended in 2020 to footings across the building’s western half and an office slab. The work used 142 injection points and 374 cubic yards of grout.<br /><br />The grout columns were intended to fill voids, reinforce weak landfill soils and reduce the effects of ongoing decomposition. The project team concluded that LMG substantially reduced settlement while limiting methane exposure and allowing manufacturing to continue without shutdown. The owner will continue annual settlement and crane-rail monitoring; localized additional treatment may be needed if movement warrants it.

Keywords

manufacturing facility

Golden Colorado

landfill settlement

methane intrusion

micropiles

low-mobility grouting

grout columns

structural performance

settlement monitoring

foundation remediation