مقاله انگلیسی رایگان در مورد پیش بینی ظرفیت باربری بار محوری نهایی شمع ها – اسپرینگر 2017

Deep foundations are mainly used in situations that the underlying soil layer is not enough capable of bearing the applied loads where it is not possible to use shallow foundations. The main objective of using piles is to transfer structural loads to a strong layer which is able to support the applied loads. Thus, the safety and stability of pile supported structures depend on the behavior of piles. In order to ensure the stability of the foundation, it is necessary to make an accurate estimation of the pile bearing capacity, particularly for pre-design purposes. This problem has been challenging for many geotechnical engineers and not yet entirely been handled due to many factors and uncertainties affecting the system behavior including complicated behavior of piles in soil, soil disturbance due to pile installation and sampling, and pile load transfer mechanism (Kiefa 1998). Based on characteristics of load transfer to the underlying layer, the staticaxial load bearing capacity of the pile (Qu) can be generally considered as the sum of end-bearing capacity of the pile (Qt), i.e. the bearing capacity of the compact stratum or a stiff layer where applied loads are transferred onto and the shaft friction capacity (Qs) that loads are carried through friction of the surrounding soil along the shaft and can be represented as the equation as follows (Niazi and Mayne 2013): Qu ¼ Qt þ Qs ¼ qt: At þXn i¼1 fsðiÞ : Asi ð1Þ where qt is the unit end bearing capacity, At is the area of the pile at tip, fs unit shaft resistance of the ith soil layer through which the pile shaft is embedded; Asi is the area providing frictional resistance with the adjacent soil in the ith layer against axial displacement It is worth mentioning that the end-bearing capacity (Qt) plays the overriding role in granular soils, whereas in cohesive soils the shaft friction capacity (Qs) dominates. In this regard, considering the type of pile is an important issue for the design and analysis of piles (Tomlinson and Woodward 2014).