<p><p><strong>References:<br></strong><em>Byrne et al. (1998)<br>Collin and Cowell (1998)<br>Lazarte et al. (2015)<br>Porterfield, Cotton, and Byrne (1994)<br>Rogbeck et al. (2003)</em></p><p><strong>Method Summary</strong></p><p>This method tests the strength of an individual soil nail by applying a specific load to a nail and measuring deflections and strain of the nail. The verification test typically loads a sacrificial nail until failure (ultimate test) or to at least 200% of the design load thus verifying the pullout resistance. Lazarte et al. (2015) defines failure as “the inability to further increase the test load while there is continued pullout movement of the test nail.” The proof test loads a certain percent of the nails (typically 5%) to a load that is usually 125% or 150% of the designed load according to Porterfield, Cotton, and Byrne (1994). Proof testing can be performed on production nails. Verification tests occur prior to installation of production nails whereas proof tests are conducted concurrently with production nail installation. A hydraulic jack is used to load the nail while the load is measured with a load cell or pressure gage, and deflections of the soil nail are measured with a dial-gage. An exact description of the testing process can be found in Lazarte et al. (2015).</p><p><strong>Accuracy and Precision</strong></p><p>This is an accurate and precise test, which is frequently relied on for screw-in soil nailing.</p><p><strong>Adequacy of Coverage</strong></p><p>A small percentage of nails tested in each soil type encountered provide adequate coverage. Depending on the site conditions, more or less tests are required. Typically 5% of installed nails are proof tested and two nails are subject to verification testing for every different soil strata encountered. In Rogbeck et al. (2003), a chart is provided to determine the amount of tests necessary based on number of nails and area covered.</p><p><strong>Implementation Requirements </strong></p><p>The tests should be performed by an individual with experience in pullout testing. The tests require a significant amount of time.</p><p><strong>General Comments</strong></p><p>Verification tests assist in producing final design values and proof tests ensure that the installed nails have adequate pullout capacity. However, the test can be expensive, time consuming, and limited in its coverage. Pullout and verification tests are used for both method and performance approach specifications.</p></p>