NUMERICAL AND EXPERIMENTAL ANALYSIS OF SINGLE PILE FOUNDATION BEHAVIOR IN EXPANSIVE ANKARA CLAY

Date

2025-7-2

Author

YILDIRIM, SEFA

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

351
views

0
downloads

Cite This

Ankara, Türkiye, has a semi-arid climate, where moisture content variations in expansive soils cause swelling movements, potentially damaging lightweight structures. Pile foundations are commonly used in expansive soils when superstructure loads need to be transferred to depths where moisture change is ignorable. To design safe pile foundations in such conditions, it is crucial to determine the necessary anchorage depth to counteract uplift forces. The soil surrounding the pile in expansive clays is typically unsaturated, and matric suction significantly influences the mechanical behavior of the pile. To achieve the objectives of this study, the Thornthwaite Moisture Index (TMI) was determined to classify the regional climate zone. Scanning Electron Microscope (SEM) images and X-ray Diffraction (XRD) results were analyzed to identify the soil mineralogy. The index properties of the soil were characterized through sieve and hydrometer analyses, specific gravity tests, Atterberg limits, compaction tests, free swell tests, and methylene blue tests. The mechanical behavior of the soil was investigated using direct shear, unconfined compression, triaxial, and one-dimensional consolidation tests. Additionally, the soil water retention curve (SWRC) was obtained using the axis translation, filter paper, and salt solution methods. The findings were then combined to derive the parameters of the Barcelona Basic Model (BBM) for numerical modeling. Furthermore, small-scale laboratory experiments were conducted to simulate the behavior of a single pile foundation in expansive clay. The displacement of the pile at varying anchorage depths was measured to determine the minimum required anchorage depth for a safe and stable design. According to the results of the experiments carried out in the laboratory, it was observed that if 3/5 of the total length of the single piles is placed in the anchor zone in the Ankara clay, there will be no movement of the pile. This study shows that Ankara-Cubuk clay, which is very difficult to predict the behavior and model because of the change in material properties depending on the water content, can be modeled using the BBM method.

Subject Keywords

Clay, Expansive Soil, Pile Foundation, SWRC, BBM, FEM

URI

https://hdl.handle.net/11511/115423

Collections

Graduate School of Natural and Applied Sciences, Thesis