Geotextile Encased Columns as a Foundation System: basic concepts, experience, and perspective
As foundation for Earth structures as embankments and dikes on soft soils geotextile encased columns can be used. This technology was introduced some 20 years ago and is now considered State-of-the-art in Germany and step by step worldwide. The GECs consist of compacted granular fill similar e.g. to common gravel columns with one decisive difference: they are confined in a high-strength woven geotextile "cylinder" (encasement). As a result, a structure with clearly defined parameters is constructed, whose behaviour is controlled by the geotextile encasement. Consequently, it works properly even in extremely soft soils and a wide range of fills including sand. Huge technological and design experience is available and design methods have been verified. The paper focuses in the presentation of this system in Colombia, where this kind of solution has not yet been applied. The principles and the main topics are explained. Additionally, some important conclusiones from studies are presented.
Until 2002 the activities in terms of research, measurement programs, design procedures and so on were concentrated mainly in Germany. Since about 2002-2003 international theoretical and practical research, measurement programs etc became more intensive because of the increasing worldwide application of GECs and the efforts to study additional aspects and applications of the system or to optimize design. Due to brevity all the publications in this context cannot be cited herein. Useful compact overviews can be found in e.g. Tandel et al. (2012a) and Tandel et al. (2012b). Generally some basics from the late 90ies were so far confirmed (e.g. Murugesan and Rajagopal (2007)). An interesting research is under run dealing with the behaviour, possible benefits and specialized design procedures in the case of seismic impact (Guler et al. 2013).