<p><p><div class="grayed-title"></p><p><figure id='attachment_7929' style='max-width:680px' class='caption alignleft'><img class=" wp-image-7929" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of pilecaps on Continuous Flight Auger piles for column-supported embankment." width="680" height="453" /><figcaption class='caption-text'> Pilecaps on CFA piles for column-supported embankment. From Brown et al. (2007).</figcaption></figure></p><p></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><div></div><h2>Project Summary/Scope:</h2><div>A new high-speed railway was constructed over alluvial soils with embankments 6 to 7 meters high. By supporting the embankments on CFA piles, applied loads were transferred to a less compressible stratum, removing the need for preloading/surcharging and PVDs to accelerate consolidation.</div><div>Subsurface Conditions: Silty clay ranging from soft to very compact. The soil had a unit weight of 19 kN/m^3, an effective cohesion value of 5 to 10 kPa, an effective friction angle of 25 degrees, and an undrained strength of 50 to 100 kPa.</div><div>For locations with embankments greater than 5 meters high, CFA piles were installed on a square grid of 2.5 meters by 2.5 meters; at some locations with shorter embankments, prefabricated vertical drains and surcharging were applied instead of CFA piles.</div><h2>Complementary Technologies Used:</h2><div>Column Supported Embankments, Prefabricated Vertical Drains and Surcharging.</div><h2>Alternate Technologies:</h2><div></p><p>Prefabricated Vertical Drains and Surcharging was considered for the project; however, the technology was only used at locations with shorter embankments.</p><p><figure id='attachment_8063' style='max-width:452px' class='caption aligncenter'><img class="wp-image-8063 " src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="A photograph showing a close up of grout at surface after auger removal in High Speed Railway, Italy." width="452" height="318" /><figcaption class='caption-text'> Grout at surface after auger removal (Brown et al. 2007).</figcaption></figure></p><p></div><div></div><div><h2>Performance Monitoring:</h2>Expected settlement was 600 mm without CFA piles, 220 mm with 23-meter long CFA piles, and 170 mm with 30-meter long CFA piles.<br><h2>Cost Information:</h2>Although CFA piles are initially more expensive than prefabricated vertical drains, they proved to be cost effective in a life-cycle cost analysis.</p><p></div><h2>Project Technical Paper:</h2><div>Pagliacci, F., Bertero, A., Sieipi, M., and Zuffi, P., (2003). “Recent developments on Continuous Flight Auger (CFA) pile: Technology, equipment and applications, Deep Foundations on Bored and Auger Piles.” Proceedings of the 4th International Geotechnical Seminar on Deep Foundations on Bored and Auger Piles.</div><h2>Date Case History Prepared:</h2><div>November 2012</div></p></p>