<p><p><strong>Reference(s):</strong></p><p><em>Dumas and Beaton (1992)</em><em>Elias et al. (2006a)</em><em>Lukas (1986)</em><em>Lukas (1995) </em><em>Mitchell (1981b)</em></p><p><strong>Method Summary<br></strong>Settlement measurements should be performed in a grid pattern over the area being compacted both during and after the compaction program. During the compaction program, an average settlement reading should be taken after each pass by leveling the ground and smoothing out the craters. They should continue for a length of time after the compaction has been completed to assess any additional time-dependent settlements. These settlement measurements can be done either by manual surveying or an automated system.</p><p><strong>Accuracy and Precision<br></strong>Surface settlement measurements are accurate but only provide a total estimate of the total settlement in an area. Specific information about the densification throughout the layer being compacted requires settlement markers at different depths beneath the ground surface.</p><p><strong>Adequacy of Coverage<br></strong>Surface settlement markers are inexpensive and the number of them needed to cover the entire compaction site is not prohibitive. However, deep settlement markers are more difficult and expensive to place. The time, cost, and number of readings required for deep settlement measurements is significantly greater than for surface measurements.</p><p><strong>Implementation Requirements<br></strong>Settlement measuring devices can be fairly inexpensive depending on the amount of automation, and placement can be done easily for surface settlement markers. Deep settlement markers are more difficult to place and require more extensive data analysis and interpretation, but can be done by most contractors.</p><p><strong>General Comments<br></strong>Settlement measurements can be used in any deep dynamic compaction program.</p></p>