Lchya Gebre2025-09-292025-06-02https://repository.mu.edu.et/handle/123456789/937Pile group foundations are widely used to support heavy structures where individual piles cannot provide adequate bearing capacity or settlement control. This study focuses on the numerical analysis of pile group bearing capacity under axial loading using PLAXIS 3D v. 2013 a finite element software for geotechnical applications. The analysis investigates the load settlement behavior of pile groups embedded in clay, considering homogeneous and layer soil profiles, using the Mohr Coulomb constitutive model to represent soil behavior. To analyze the influence of a group of piles on bearing capacity and load transfer mechanism among them, the research includes the use of different pile configurations such as changes in the pile spacing, geometry, and even material properties. In behavior of the structures tested, contact elements have been used to model the integration of piles with soil whereas the model boundary conditions are properly placed so as to avoid displacement that is deemed arbitrary. Numerical results obtained from the simulations are validated against results obtained from traditional analytical methods like Meyerhof’s and Vesic’s equations. The key findings state that the pile group bearing capacity is highly associated with the multiplier of pile spacing, and interaction between the pile and soil. The investigation also underlines the necessity to employ modern numerical methods, like PLAXIS 3D, to solve complex interaction of soil and structure that is common place in the analytical approach. This research offers some crucial information to the geotechnical engineers as aid in development and analysis of pile foundations to be more precise and more reliable. The results highlighted the importance of combining classical techniques with numerical ones in order to achieve more secure and more competitive design concepts for the foundation.enPile bearing capacityPLAXIS 3Dfinite element analysisSoil-pile interactionDeep foundationsThesis