Problem
RaiseRite was brought in to investigate subgrade issues beneath a section of a highway ramp after visible settlement of the highway shoulder was observed near a recently installed underground culvert. The signs of movement in the shoulder raised concerns about the stability of the underlying soils, prompting the need for a detailed assessment and a long-term solution.
To get a clear picture of the subgrade conditions, RaiseRite performed Dynamic Cone Penetrometer (DCP) testing at five locations – four along the culvert path and one in an undisturbed area to serve as a control. The results helped pinpoint areas of weakened or disturbed soil, particularly in the upper layers of the embankment.
Solution
Based on the findings, RaiseRite recommended a project-specific remediation strategy using HF402 polyurethane foam. The foam was injected into the subgrade to densify loose soils and beneath the highway slab to underseal and fill any hidden voids. Injection points were spaced in a 4-foot grid to ensure even coverage and full support. The process was fast, non-invasive, and required little disruption to traffic.
RaiseRite’s combined testing and repair plan delivered a clear path to restoring subgrade integrity – ensuring the highway ramp is now stabilized and ready for long-term performance without the need for major reconstruction or ongoing maintenance.
