الفهرس 
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Abstract
Negative skin friction on piles is a common phenomenon that represents a severe problem when piles were installed in soft clay due to consolidation process. When piles are horizontally loaded the response process is to carry the horizontal load to the surrounding soil by soil lateral resistance. The upper part of piles tends to move horizontally in the same direction of load. This resulted in developing rotation and bending moment or complete shift of the piles. The piles will push soil ahead of their surface in the direction of load which creates a compression stress and shear stress inside the soil layer that will resist the pile shift. Hence the equilibrium condition should be between the applied horizontal loads against the resistance of soil developed on full piles surfaces. This thesis was dedicated to study the influence of the horizontal loading at the pile top on the induced negative skin friction and drag loads along the pile surface utilizing FEM ABAQUS software on single pile and pile groups. Results showed that horizontal loads substantially reduced the NSF and drag loads compared to piles not subjected to horizontal loads due to reduction of soil settlement caused by horizontal movement of pile and soil. Then a numerical study was made to scrutinize the influence of two new geometries of piles were thought that they could decrease the settlement of soil adjacent to pile. As it is known the piles are used in groups so the study is heading to the effect of the new shapes of on single piles then piles in groups. The results of numerical analysis showed large decrease in the soil settlement and in consequence large reduction of negative skin friction on piles and drag load. The group effect shielding effect was substantially increased when modeling pile groups. The new shapes of piles (Ridged pile and grooved pile) provided acceptable results decreasing the negative skin friction values of piles when they were subjected to horizontal loads at the top. The comparison between square piles and circular piles showed that square piles developed large enhancement on the behavior of NSF induced on single piles and pile groups. Parametric study for both square and circular piles indicated that geometry of piles plays an important role in the behavior of pile when subjected to consolidation process. Furthermore, when lateral loads influenced on the piles, they significantly changed the results of NSF