<p><p><div><h2>Project Summary/Scope:</h2>Helical (screw-in) soil nails were used to support a temporary excavation for a year up to 40 feet high for the construction of a new reservoir. The soil nail wall is on the west side of the site and a county road is about 10 feet back from the face of the cut. The wall was approximately 120 feet long and 40 feet high. A triangular pattern was used for the layout of the nails. The computer programs SLOPE/W and Caltrans SNAILWin4.1 were used to analyze design and slope stability.</p><p>Subsurface Conditions: Primarily weathered basalt, towards the surface there was medium stiff to very stiff silt varying from trace clay to clayey.</p><p>The temporary cut performed satisfactorily.<br><h2>Alternate Technologies:</h2>Conventional soil nails.<br><h2>Performance Monitoring:</h2>Two nails were tested to failure (verification tests) and 5% of all the nails installed were tested to 150% of the design load (proof tests).<br><h2>Cost Information:</h2>An exact cost was not available but the helical soil nails were less expensive than conventional drilled nails.<br><h2>Case History Author/Submitter:</h2>Personal communication, T. Kimball, Project Engineer, 2009.<br><h2>Date Case History Prepared:</h2>November 2012</p><p></div></p></p>