GeoStabilization International® was contracted to provide emergency design-build services for a failed rock slope in NW Portland for Multnomah County, Oregon. The scope of work required stabilization of the lower fractured rock slope and upper mantle of overburden soil. The scarp regressed back into private property approximately 5 feet. A soil nail wall was constructed at the top and backfilled with controlled low strength material to regain the lost property. Approximately 60 rock anchors and 2,200 SF of high strength galvanized rockfall mesh was installed on the fractured rock face. Anchor installation was completed from the bottom and top of slope without the need for intermediate benches.
A variation of karst sinkhole grouting is the grouting of mined coal seams and workings located below existing infrastructure that exhibit the potential to propagate to the surface and cause sinkholes and/or subsidence.