Using geopolymer coated and uncoated geotextile as a hybrid method to improve uplift capacity of screw piles in cohesionless soil

In this research, experimental studies and numerical analyses were carried out to investigate how the usage of geotextile and geopolymer coated geotextile as a hybrid method changes the uplift behavior of the screw piles in cohesionless soil. In this context, traditional pile behavior, the effect of different number of helixes and embedment depths on screw piles, the mechanism of geotextile and the effects of geopolymer coating process were investigated. In addition, experimental studies were modeled by using Plaxis 3D and parametric studies were carried out after verification between the results of experimental study and numerical analysis. In the numerical analysis, a segmented helix model consisting of four 90-degree slices was developed instead of the planar helixes commonly used in the literature. For further investigation of the effectiveness of hybrid method, parameters such as improvement ratios and breakout factors were calculated. When the results obtained within the scope of the study were evaluated, the geopolymer coating process increased the bearing capacity of the geotextile by 24 % at 27 % less elongation. It was also seen that uncoated and geopolymer coated geotextile increased the screw pile performance in terms of improvement ratios by 294 % and 364 %, respectively.