<p><p><strong>References:<br></strong><em>Chu and Yan (2005a, b, c)<br>Chu et al. (2006)<br>Schaefer et al. (2016)<br>ISSGME (2008)<br>SHRP 2 Phase I Technology Assessment (2008)<br>Yan and Chu (2003a,b)</em></p><p><strong>Method Summary</strong></p><p>Piezometers are used to measure and monitor pore water pressures before, during, and after vacuum preloading. Once installed, the piezometer should be read on a regular schedule. Piezometers provide a good indication of the degree of consolidation. By assessing the excess pore water pressures before, during, and after vacuum preloading, the degree of consolidation can be determined. Interpretation of piezometer data requires knowledge of the loading history of the site and excess pore water pressures that may exist before vacuum preloading.</p><p><strong>Accuracy and Precision</strong></p><p>Piezometers provide a good assessment of pore water pressure. Readings can be influenced by the location of the water pressure transducer. An advantage of using piezometers is that the readings are not greatly influenced by the operator.</p><p><strong>Adequacy of Coverage</strong></p><p>Piezometers provide a limited area of coverage. Multiple piezometers are required laterally and to varying depths to provide a site profile of pore water pressures.</p><p><strong>Implementation Requirements </strong></p><p>Installing piezometers requires a drill rig and the necessary materials to construct a piezometer. After installation, the process to read piezometers is simple.</p><p><strong>General Comments </strong></p><p>Piezometers provide a good indication of the progress and final product of a vacuum preloading project. By assessing the excess pore water pressures before, during, and after; the degree of consolidation can be determined. Understanding the pore water pressure before and after vacuum preloading will help to confirm settlement data and the rate of consolidation. Interpretation of piezometer data requires knowledge of the loading history of the site and the pore water pressures existing before vacuum preloading and fill preloading. According to Schaefer et al. (2016), “Piezometers are used for both calculation of achieved consolidation rate and excessive build-up of pore pressure that is an indication of potential failure.”</p></p>