EXPERIMENTAL ANALYSIS OF GEOTEXTILE ENCASED COLUMNS USING LAPONITE
Granular columns, Transparent soil, Soft clay, Laponite RD®, PIV, Experimental model
Granular columns inclusions in soft clays emerged as a solution to improve the bearing capacity and accelerate the settlement by consolidation in this type of soil. However, due its low resistence, the material doesn’t provide sufficent confinement to the granular element, that may collapse when loaded. Thus, the geotextile encased granular columns (GEC), semi rigid elements, arised as an alternative to solve this problem. This work propose the development of experimental scale models using Laponite RD®, a type of transparent clay, and the PIV (Particle Image Velocimetry) technique, in order to non-intrusively study the effect of executive tube penetration and the loading on conventional and encased granular columns. So far, five experimental models (5) have been executed where, in addition to the presence or not of a geosynthetic case, the relative density of the granular material in the individual column was varied. It was captured images during the penetration and loading process. The parcial results showed that the column executive process can laterally move the clay up to distance of 7R, with a magnitude close to 0.1R, wich can result in a displacement and deformations on previously excuted columns. Nevertheless, both the load x displacements curves and PIV analysis showed the effectiveness of including a geosynthetic case, as there was an increase in the load capacity associated with a reduction in deformations. The columns with lower relative density showed larger final displacement values and, when considered the encased column, it was observed a bending process that resulted in the collapse of the element