Three-dimensional finite element analysis of end-bearing pile groups for negative skin friction estimation

---

Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2023

Tezin Dili: İngilizce

Öğrenci: MEHMET İLÇİOĞLU

Danışman: Nabi Kartal Toker

Özet:

Negative skin friction (NSF) is a phenomenon which occurs when soil surrounding the piles settles more than piles due to consolidation. NSF may result in dragload and engineering problems such as: differential settlements, damage on the piles and foundation failure. Three-dimensional finite element analysis of end-bearing pile groups for negative skin friction estimation The conventional analytical methods assume that NSF fully mobilizes above a neutral plane where settlement in the pile and soil are equal; leading to overestimation of dragload. Although there are numerous studies in the literature to investigate the behavior of single piles under the influence of NSF, there are very limited investigations on the behavior of pile groups and more specifically end-bearing pile groups. The presence of adjacent piles complicates the evaluation of the effects of soil-pile interaction. In this study a 3D finite element analysis (FEA) is initially conducted on a single pile based on a reference case study and model is validated against field measurements. Further FEA were performed to conduct parametric studies on pile and soil properties to understand the magnitude and distribution of NSF, dragload and the influence of group effect. The results of FEA were compared with a conventional analytical method and tributary area method. Finally, a new equation is proposed for accurate predictions of the NSF without a need to perform FEA during challenging and rushed working conditions in the industry.