A state Department of Transportation in the Northeast had been monitoring a failing fill slope along a rural road that served as the only access for a group of residents (and a large sod farm) since 2000. Traditional repair methods including sheet piling, slope flattening, a reinforced soil slope, and an MSE wall either involved temporary road closure, right of way acquisition, encroachment onto an easement maintained by the state’s Society for the Protection of Forests, or were beyond the designated project funding levels. Over Mother’s Day Weekend in 2006, the area received over 10-inches of rain in a 24-hour period, causing the slope to drop more than six inches. GeoStabilization International® visited the site and presented a design that would not require easements, right of way acquisition, would maintain traffic in one lane throughout the repair, and could be completed in a fraction of the time and for a fraction of the cost of the “traditional” options.
GeoStabilization installed over 200 galvanized perforated launched soil nails faced with high capacity galfan-coated wire mesh. Topsoil was installed over the wire mesh and seeded. By completing all the work from the roadway platform, disturbance to the forest below was completely avoided.
The site had been monitored by state’s Geotechnical staff using inclinometers for over 8 years and has shown no movement.
Gonowabie Road is a historic logging road now serving vacationers and homeowners who enjoy the beauty and tranquility of Crystal Bay in Lake Tahoe.