A midstream transmission group asked GSI® Energy to look at an urgent slide on this large cross-country natural gas transmission line. The slope appeared to have been disturbed by landowner excavation activities, causing a large landslide. The earth movement caused nearly four feet of horizontal deformation of the line spanning more than 175 linear feet, putting the 24 inch high pressure line in danger of imminent rupture. GSI® Energy completed a field survey along with other measurements and photographs. This data was used to produce field sketches, then developed into an estimate, and eventually turned into a global stability model to verify the field observations, and initial conceptual design approach. GeoStabilization’s engineers accomplished their site visit, all modeling, and design within three days at no cost. The initial design called for multiple rows of up to 40 foot long Self-Drilling SuperNails™ and a reinforced shotcrete panel both above and below the active pipeline. During construction, GeoStabilization’s crews encountered bedrock at shallower than expected depths in some locations, allowing GeoStabilization’s engineers to re-model and revise the design to include shorter SuperNails™. The refined design saved the client nearly 30% over the original proposal.
When a portion of Sunset Road on Vashon Island in King County experienced a landslide with previous surficial erosion issues, GeoStabilization International ® provided a design/build/warranty solution. To restore the approximately 70-foot length of damaged road, GSI installed an array of SuperNails ™ to stabilize the slope and faced it with galvanized high-strength mesh.