Geotextile encased columns

Another soil replacement method uses Geotextile Encased sand Columns (GEC). These columns can be installed in very soft soils. They can accelerate the consolidation process, increase the shear strength and reduce the settlements of soft subsoil. 

At first sight geotextile encased columns do not differ much from common sand drains. However, in contrast to sand drains, the geotextile encasing 

Lateral support of geotexdle encased sand column 

The resulting sand piles are usually 0.4-0.8 m in diameter and installed at typical grid spacings ranging between 1.5 and 3 m. 

With a geotextile encased column, the horizontal support of the soft soil can be much lower than for non-encased columns due to the radial supporting effect of the geotextile casing. The colunms act simultaneously as vertical drains, but the main effect is the transport of the load to a deeper bearing layer. To carry the high 

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Sand compaction piles (closed end casing) 7.6.5 Geotextile encased columns 7.6.6 Dynamic replacement ... 

Raithel, M., Kempfert, H.G. and Kirchner, A. Geotextile-Encased Columns (GEC) for Foundation of a Dike on Very Soft Soils, Wurzburg, 2002. 

The following sections provide a basic overview on modeling, design, and the corresponding requirements for geosynthetic reinforcement, with an emphasis on basal-reinforced embankments, geotextile-encased columns (GECs), and pded embankments. 

Vertical stability analysis of geotextile-encased columns... 

Geotextile encased sand columns clay, peat... 

Geotextile encased granular column 0 Soft soil Rrm bearing layer... 

The use of geotextiles to reinforce soft foundation soils has progressed from the earliest applications some 40 years ago to the current status of widespread use and success. This chapter presents three major application areas (1) basal reinforcement, (2) geotextile-encased granular columns, and (3) geosynthetic piled foundations. In addition to the descriptions, elements of design, and information on performance, a specific project example was given for each topic. Further advances can and should be made, but we beheve that the current state of the practice in the selected applications is properly reflected here. 

Alexiew, D., Kiister, V., Raithel, M., Detert, O., 2012. 15 years of experience with geotextile encased granular columns as foundation system. In Proceedings of International Symposium on Ground Improvement IS-GI, Brussels 2011, ISSMGE TC 211. 

Centrifuge model CT-C (Fig. 24.4) tests different configurations for the hybrid resistance measure initially tested in model CT-B, to evaluate the influence on the performance. As the figure shows, the geotextile extends in both cases to half the depth of the liquefiable deposit (9 m) while the narrow densified column encased in the geotextile extends to the bottom of the liquefiable layer, in one case, and to the same depth as the geotextile in the other. 

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