مقاله انگلیسی رایگان در مورد رفتار پی گسترده شمعی در خاک رس – الزویر 2018

The piled-raft is a geotechnical foundation consisting of the three elements raft, piles and soil. Burland (1977) proposed that the piles can be used to reduce the settlement of the raft foundation. In piled-raft foundation, the total load of the superstructure is partly carried by the piles and the raft. The distribution of total load among the piles, raft and soil depends on their relative stiffnesses. Based on the dimensions of the raft and piles, the piled-raft has been classified as a small piled-raft (Br/Lp < 1) and large piled-raft (Br/Lp > 1) (Viggiani, 2001; Sanctis and Mandolini, 2006; Mandolini et al., 2013). In a small piled-raft, the flexural stiffness of the raft is usually high and the differential settlement does not represent a problem. Here, the primary reason to add the piles is to achieve a sufficient factor of safety against the bearing failure. However, in a large piled-raft, piles are added essentially to reduce the settlement. Poulos (2001) indicated that the 3-D numerical modeling is the most reliable method for the analysis of the piled-raft foundation in a clay soils. The maximum settlement, differential settlement, raft bending moments and shear force, axial loads and pile bending moments are considered as crucial parameter for optimum design of piled-raft foundation. Several researchers have been investigated the settlement (Prakoso and Kulhawy, 2001; Cho et al., 2012; Sinha and Hanna, 2016) and bearing behavior (Reul, 2004; Sanctis and Mandolini, 2006; Lee et al., 2010) of a piled-raft foundation on clay soils by numerical modeling. Oh et al. (2008) conducted a study on the piled-raft foundation in sandy soil by numerical modeling. They reported that with increase in raft thickness and pile spacing, the bending moment of the piled-raft increased. The different design aspects of the piled-raft foundation have been reported by Seo et al. (2003), and Reul and Randolph (2004). Ghalesari et al. (2015) suggested that the piled-raft foundation can be adopted as offshore foundation to reduce the settlement and to enhance the bearing capacity of the foundation. Furthermore, Poulos and Devdas (2005), Poulos and Bunce (2008), Poulos et al. (2011), Rabiei and Choobbasti (2016) indicated that the piled-raft can be used as an effective and economic foundation alternative for tall buildings to control the settlement and to enhance the bearing capacities. In addition to this, Nguyen et al. (2014) conducted a parametric study of large piled-raft foundations in sandy soil through finite element modeling. They indicated that the concentrated pile arrangement method can help to considerably reduce the settlements and bending moments of the raft. However, very few parametric studies by means of numerical modeling have been reported for the large piled-raft foundation on a clay soils. Therefore, the effect of different parameters on large piled-raft foundation needs to be investigated. The intended large piled-raft foundation can be used for the construction of residential or commercial buildings situated near onshore line where mostly undrained conditions prevail.