الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
One of the most severe issues is building on soft clay soils, which exist in many areas throughout Egypt and the world. Most of the time, the applied vertical loads on foundations buried in soft clay are satisfied. However, soft clay soils typically cannot withstand large sideward loads. Thus, it is necessary to enhance the lateral behavior of the foundations to serve numerous practical problems. This dissertation employs tridimensional numerical analyses to assess the impacts of ground enhancement techniques on boosting the lateral behavior of rafts over piles buried in soft clays. Additionally, the effects of boosted soil area and location were also probed. Other approaches to assess the sideward behavior of piled rafts were probed in this dissertation, such as augmenting raft thickness, expanding pile diameter, increasing clay cohesion value, and applying compound sideways and vertical loads to rafts over piles. The numerical analyses were conducted by tridimensional finite element software (Plaxis 3D version 2013). The analyses comprise studies on a full-scale raft (14 ×12 m) with a thickness of 0.7m over 7×6 piles with 4Dp center-to-center spacing, diameters of 0.5m, and 20m length. To assess the influence of soil enhancement techniques on the sideward demeanor of pile rafts, series of FEA were run after enhancing a portion of authentic soft clay by substituting this portion with sand or gravel fill and using jet grouting to augment the soil’s shear strength and stiffness. The results revealed that using diverse ground enhancement techniques (jet grouting, gravel backfill, and sand backfill) have an essential impact on boosting the lateral demeanor of piled rafts buried in soft clays. In addition, extending the dimensions of enhanced clay soil boosts the piled raft’s sideward resistance. Nevertheless, upper-enhanced clays have more sideward resistance than deeper-enhanced clays. It was also found that the existence of vertical loads aids in enhancing the foundations’ sideward performance. Furthermore, as pile diameters and raft thicknesses enlarge, the lateral behavior of rafts over piles enhances.