In-Ground Dynamic Stress Measurements for Geosynthetic Reinforced Subgrade/Subbase

This study documents field measurements from controlled test sections with in-ground piezoelectric earth pressure cells embedded above and below different polymer geosynthetic materials placed at the interface of soft clay subgrade and crushed limestone subbase. A control section with no geosynthetic layer was monitored for comparison. In-ground stresses were monitored during vibratory roller compaction and trafficking under a heavy loaded truck. One of the geogrids is a relatively new product for which there is less field performance data than the more traditional biaxial geogrids. Results from this study demonstrate better performance of the new geogrid test section compared to other test sections as verified using compaction and rut depth measurements. Improved performance is attributed to higher lateral restraint of the subbase layer and reduced horizontal stresses in the soft subgrade layer under loading.