الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Rafts on piles are considered one of the most effective techniques used either when heavy loads of high-rise buildings are to be transmitted to the deeper soil deposits to fulfill the bearing capacity limits or to control the settlement of these heavy buildings by transmitting the loads into more stiff layers of soil. Hence, so many studies have been performed to help us understand the behavior of the group of piles under reinforced concrete rafts.
The main objective of this research is to investigate the behavior of the group of piles under reinforced concrete rafts in different soil types and the interaction between the group of piles and the surrounding soil clusters to compare that behavior with the single pile behavior in both terms of pile group action and pile group efficiency.
The research presents a numerical study adopting a finite element analysis method using three-dimensional modeling of the problem of the behavior of the group of piles in overconsolidated clayey soil. A case study reported at Alzey, Germany (1974) of a highway bridge rested on two pile caps each rested above 6 piles is undertaken and modeled in three-dimensional models with different constitutive laws and the results of the performed models are compared to the actual readings measured at the field during and after construction.
Finally, a parametric study is performed to study the effect of different factors affecting the behavior of the group of piles compared to the behavior of the single pile in both sides of bearing capacity and vertical deformation in overconsolidated clayey soil and very dense sand.
The thesis consists of these six chapters:
Chapter (1) is the introduction to this research; it discusses the importance, the scope and the main objectives of the research.
Chapter (2) is a literature review which briefly discusses through the past researches the behavior of the group of piles in the different soil in terms of pile group action (settlement of group of piles in comparison with it for the single pile) and also the pile group efficiency (the ultimate bearing load for group of piles divided by the number of piles compared to the load of a single pile).
Chapter (3) presents a brief discussion about the finite element method including analysis sequence and different types of elements that may be used in the analysis. Also, different constitutive laws in geomechanics are highlighted. In addition, the utilized material models’ formulations are provided. Finally, the finite element analysis program ”Plaxis”, which is used during this research, is briefly discussed.
Chapter (4) in this chapter a discussion of a case study description including the actual location, soil profile, soil parameters, number of piles, pattern of piles, and the applied loads. In addition, the monitored deformation values during the construction and the operation of the bridge are introduced. A set of three-dimensional numerical models were established to investigate the behavior of the group of piles in the defined soil and the resulted deformation and pile loads. Finally, the comparison between the monitored results and the numerically predicted response of the three-dimensional model is presented at the end of this chapter to confirm the ability of the numerical modeling three-dimensional program to simulate the reality with close results.
Chapter (5) a parametric study is presented with its results in this chapter as it was conducted to investigate the effect of different parameters on the load carrying capacity of the stone column. The effect of piles spacing, piles length, and type of soil on the pile group behavior in terms of ultimate load and settlement.
Chapter (6) the summary and the conclusions of this research are presented ended up with suggestions for future studies and research topics relevant to the subject.