The construction of embankments on soft saturated soils can be a challenge due to the low shear strength and high compressibility of these soils. The same may be true for constructions on porous collapsible soils, because the collapse of the soil structure can lead to large foundation soil deformations leading to damage to the embankment, particularly in the case of bridge abutments. Conventional piles and granular columns have been used to stabilize such embankments when there are limits for embankment settlements. More recently, geosynthetic-encased granular columns have been increasingly used as an alternative solution. This study examined the performance of geosynthetic-encased columns for the stabilization of embankments on porous collapsible structured unsaturated soil. Field load tests were performed on conventional sand and gravel columns and on geotextile-encased sand columns and on geogrid-encased gravel columns. During testing, the collapse of the surrounding soil was induced by water injection through the granular column top to investigate the influence of the casing on the column performance. The results obtained show that significant increases on pile load capacity can be obtained depending on the materials used and construction conditions. The effects of foundation collapse can also be reduced with the use of a geosynthetic casing in the granular column.

Geosynthetics have proven to provide sustainable solutions for geotechnical and geoenvironmental problems when used with natural materials. Therefore, the expected benefits to the environment when geosynthetics are associated with unconventional or alternative construction materials will be even greater. This paper addresses the use of geosynthetics with wasted materials in different applications. The potential uses of alternative materials such as wasted tires, construction and demolition wastes, and plastic bottles are presented and discussed considering results from laboratory and field tests. Combinations of geosynthetics and alternative construction materials applied to reinforced soil structures, drainage systems for landfills, barriers, and stabilisation of embankments on soft grounds are discussed. The results show the feasibility of such combinations, and that they are beneficial to the environment and in line with the increasing trend towards a circular economy and sustainable development.