<p><p><strong>References:<br></strong><em>Schaefer et al. (2006)</em></p><p><strong>Method Summary</strong></p><p>Calculating the displacement ratio, D_R, is a method of evaluating the stability of sites where, in addition to the vacuum preload, a fill preload is utilized. The displacement ratio is measured along and transverse to the perimeter of the fill. The displacement ratio is defined as “the maximum cumulative horizontal displacement of the inclinometer divided by the cumulative settlement determined from an adjacent settlement plate” (Schaefer et al. 2016). The displacement ratio should be measured during and after placement of the fill to monitor inward and outward lateral movements. A significant increase in the displacement ratio indicates site stability concerns. In general, a displacement ratio of 0.2 or less indicates a stable site.</p><p><strong>Accuracy and Precision</strong></p><p>The calculated displacement ratio is as reliable as the settlement plate and inclinometer readings.</p><p><strong>Adequacy of Coverage</strong></p><p>The adequacy of coverage depends on the number of settlement plates used.</p><p><strong>Implementation Requirements </strong></p><p>The calculation to determine the displacement ratio is straightforward and simple.</p><p><strong>General Comments </strong></p><p>The displacement ratio is typically only calculated for sites requiring the use of fill preload. According to Schaefer et al. (2106), if the fill is placed quickly a displacement ratio approaching 0.4 might be measured. Figure 2-11 in Schaefer et al. (2016) shows a typical plot of the displacement ratio versus time measured for a multi-stage fill.</p></p>