<p><p><strong>References:<br></strong><em>Berg et al. (2009)<br>Christopher et al. (1990a)</em></p><p><strong>Method Summary: </strong></p><p>RSS is cost-effective soil retaining structures that can tolerate much larger total and differential settlement than other type of retaining structures. The facing elements and backfill materials would affect the RSS settlement magnitude significantly. Consolidation test is recommended to perform to predict the consolidation properties of backfill and foundation materials, such as magnitude and rate of consolidation, short and long term consolidation. Settlement criteria should be established at preliminary design stage, which can be used as reference that what type of backfill materials should be used.</p><p><strong>Accuracy and Precision </strong></p><p>The deformation and settlement analyses are obtained from conventional settlement computations, which to be refereed as reference for selection facing connections or backfilling sequences. In general, this settlement analyses tend to be conservative. Additionally, it is difficult and inaccurate to predict the horizontal deformation.</p><p><strong>Adequacy of Coverage </strong></p><p>This QC/QA procedure may require a large number of measurements to determine the performance of the system, which detailed outlined in specifications and depend on specific project requirements.</p><p><strong>Implementation Requirements </strong></p><p>A series of testing experiments are recommended to perform to obtain the engineering properties for in-situ and backfill soil including unit weight and dry weight as well as consolidation parameters.</p><p><strong>General Comments</strong></p><p>By performing both laboratory and in-situ testing, the consolidation properties of in-situ and backfill materials can be obtained, and settlement analyses including total and differential settlement is one of the important steps involved in the evaluation of static external stability, which can help to select the performance criteria.</p></p>