الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Steel tube piles have been increasingly used as deep foundations for offshore structures or onshore structures in weak soil formations. These piles are usually open-ended and installed to their final level using suitable hammers or vibrators relying on the subsurface conditions. Meanwhile, soil plug (SP) forms inside the employed tube pile during driving or installation; moreover, it affects the bearing behavior and the total pile resistance. The forming of plug relies on different factors, e.g., pile thickness, diameter, length, and soil condition. The experimental tests have been performed on a single pile and also pile groups. All tube piles were tested using the well-graded sand collected from the Egyptian desert, and the sand was prepared at medium density (Dr=55%) using a raining technique in lap. Different parameters are considered: different pile thickness, different pile diameter, different pile length/diameter ratio (L/D), and soil condition. Also, a study of the influence of pile length/diameter ratio (L/D) and submerged state on group efficiency ().
Additionally, single pile resistance has been studied using numerical simulations and analytical approaches and an assessment between the mentioned techniques and the experimental results. The model pile tests showed that the value of plug resistance in open-ended tube pile is typically in the order of 50% to 70% the ultimate load capacity of open-ended tube piles. And is influenced by pile thickness, pile diameter, pile length, and submerged conditions. Simultaneously, the plugging influence of open-ended tube piles increased with increasing pile thickness and embedded pile length. But, the plugging influence decreased with increasing pile diameter.
The ultimate load capacity of open-ended tube piles increased with increasing the embedded pile length. It must be noted that the influence of pile length on the ultimate pile capacity is greater than the influence of pile diameter; this refers to the pile length has a significant effect on ultimate pile capacity. This is due to an increase in the influence of SP. The ultimate load carrying capacity for tube pile under dry conditions is almost more significant than those of submerged conditions. It must be noted that the influence of the submerged state decreases the ultimate pile capacity to equals from 50% to 60% of ultimate pile capacity in the dry state for the same pile diameter and pile length. This means that the submerged state has a significant effect on the ultimate group capacity. The ultimate group capacity is increased with increasing the pile embedded length, and the group efficiency () is decreased with increasing the pile embedded length. It may be due to an arching action effect of sandy soil on the piles.