الفهرس 
CHAPTER 1Only 14 pages are availabe for public view
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Abstract
Structural skirts are vertical or inclined walls that encircle the soil mass beneath the footing. They improve shallow footing load-settlement behavior by restricting the soil and containing the soil plastic flow. Limited studies comparing the load-settlement behaviors of skirted foundations of different shapes are available. Therefore, this study highlights the effects of skirts on the load-settlement behavior of shallow footing through a comparative study of the behavior of square and circular footing. Various small-scale physical models were developed on a circular and square footing with different skirt depths to investigate the effect of skirt depth, skirt cell shape, footing shape, and footing width. 3D finite element models were conducted through experimental findings using PLAXIS 3D software. These models were conducted to highlight the effect of the skirt side roughness, the skirt thickness, the soil compressibility, foundation size, number of skirts, and the skirt depth on the load-settlement behavior of the skirted foundation. Moreover, a comparison of the behavior of skirted foundation and pier foundation was developed. Results of small-scale laboratory models show that using the aforementioned skirted foundations improves the load-settlement behavior of loose sandy soil more effectively than compacted soil, making them a good alternative to deep foundations for soft soil at the surface. Under the current study conditions and variables, such skirts increase the ultimate load by up to 5.67 and 8.97 times for square and circular footing having a skirt depth ratio of 1.50, respectively. Furthermore, the reduction in settlement for the shallow footing is found to be >38.0%. This study illuminated the effect of skirt cell shape, where the improvement in the load-settlement behavior was greater for the circular skirted footing than for the square when both had the same width and skirt depth. The finite element results of the load-settlement curves and bearing capacities were in close agreement with the experimental findings. The 3D finite element model results highlighted the most affecting parameter on the load-settlement behavior of the skirted foundation. As the improvement in the load-settlement behavior becomes much greater for the rough side interface of the skirts, for small internal friction angles, for small footing sizes, and greater skirt depths. While the thickness of skirts and the number of skirts increase the foundation system rigidity but have almost no effect on the load-settlement behavior. This study illuminated the effectiveness of using a skirted foundation instead pier foundation as the results of the bearing capacity for the pier foundation are too close to the skirted foundation.