Experimental analysis of geocell effects in road infrastructure applications

Depending on the project traffic on highways, the total thickness of the foundation and sub-base layers can reach 70 cm. In addition, if the CBR of the pavement base is less than 8%, the pavement base must be excavated and a protective layer built of selected granular material. In summary, depending on the project traffic and the bearing capacity of the pavement base, the layers to be constructed from unbound granular materials in a flexible pavement section can be of very large thickness in total. Manufacturing in large thicknesses undoubtedly prolongs the project duration and also causes high project total costs. In this study, the efficiency of geocell elements placed between low bearing capacity silty clayey sand (SM) sub-base layer and well-graded gravel (GW) type stabilized plantmix foundation layers were evaluated. In addition to the reference experiment without geocells, 4 large-scale plate loading experiments with geocells were performed. Under the axial stress of 200 kPa, which is accepted as the standard load, and 1750 kPa, which is considered as the overload, the settlement reductions due to the horizontal and vertical distances with the central region were investigated. Compared to the reference section, the settlement reduction, which reaches 78% under 25 kPa, decreases to 55% at 200 kPa levels. With the increase in vertical stress, there is a serious decrease in the recovery levels from 500 kPa and it becomes completely unusable when 1000 kPa is exceeded. The most effective behavior was obtained in large geocells with a size of 660 mm. Reinforced soils resist tensile stresses and the amount of settlement is significantly reduced when geocell material is used in the underground layers. Thus, the service life of the roads is increased and the maintenance-repair costs are reduced.