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Construction methods
Published in Emilio Bilotta, Renato Casale, Claudio Giulio di Prisco, Salvatore Miliziano, Daniele Peila, Andrea Pigorini, Enrico Maria Pizzarotti, Handbook on Tunnels and Underground Works, 2023
P. Grasso, A. Lavagno, G. Brino, M. Cardu, C. Martinelli, C. Todaro, A. Carigi, G. Cotugno, D. Peila, M. Concilia, S. Bechter, M. Bringiotti, D. Nicastro, V. Manassero, T. Peinsitt, S. Santarelli
Generally, piles are used to transfer the construction loads through soils with low bearing capacities or through free water into solid subsoil. With the development of concrete technology in the 20th century, driven piles made of reinforced concrete were implemented to a greater extent. For all these types of piles, the layers of soil are always displaced by the cross section of the pile. The displacement can be affected by impact driving (hammering), vibrating or drilling; in function of the system, it can be a full (as FDP) or a partial (as augered) displacement pile when just a proportion of the soil volume is brought to the surface through rotary drilling. A drilled pile is referred to when the volume of soil equal to the cross section of the pile is brought to the surface. According to the execution method another distinction is made between precast piles and cast-in-place piles (see EN 1536).
Design of axially loaded piles — United Kingdom practice
Published in F. De Cock, C. Legrand, Design of Axially Loaded Piles European Practice, 2020
J.D. Findlay, N.J. Brooks, J.N. Mure, W. Heron
The pile types in use in the UK have, of course, been influenced by the basic factors which affect the installation of piled foundations. Load transference to the soil or rock is achieved by a combination of both end bearing and shaft resistance and is dependent not only on the behaviour of the pile, but also on the characteristics of the chosen installation procedure. The selection of appropriate pile types is generally dependent upon the following: underlying soil conditions, including groundwater levelsthe nature and size of the loads to be supported by the foundationsproperties of the pile materials and characteristics of installation equipmenteffects of environmental and cost constraints
Deep foundations
Published in Jonathan Knappett, R. F. Craig, Craig’s Soil Mechanics, 2019
Jonathan Knappett, R. F. Craig
Static load testing is the most common form of pile testing, and the method that is most similar to the loading regime in the completed foundation. Figure 10.17 shows the set-up of a static load test. A hydraulic jack is used to push the pile under test into the ground (for a conventional compression test), using either the dead weight of kentledge (typically blocks of precast concrete or steel, Figure 10.17(a)) or a series of tension piles/anchors (Figure 10.17(b)) to provide the reaction. If kentledge is used, the weight must be at least equal to the maximum test load, though this is normally increased by 20% to account for variability in the predicted capacity. Other nearby working piles may be used as tension piles as long as they have been designed to sufficiently carry the maximum tensile loads that will be applied during the load test (see Section 10.5). An in-line load cell is used to measure the force applied at the pile head, while the displacement of the pile head should be measured using local displacement transducers and by remote measurement using precision levelling equipment. The former method is generally more accurate, though may be affected by any ground settlements around the test pile.
Evaluation of passive pile analysis methods using three-dimensional finite element analysis
Published in Geomechanics and Geoengineering, 2023
M. S. Morsy, Y.M. El-Mossallamy, A. Salah
Several factors that could affect passive pile performance were studied using numerical modelling. These factors include construction sequence, pile-soil relative stiffness, and pile group configuration. Higher pile-soil relative stiffness and/or slower load application resulted in less pile head displacement (Yang et al. 2017, Al-abboodi and Sabbagh 2019). Moreover, the value of lateral earth pressure induced by an adjacent surcharge acting on the piles row closer to the surcharge is higher than other rows (Zhao et al. 2008). Another factor that could affect a passive pile capacity is the contamination of the adjacent soft soil by a fuel oil, as indicated by Karkush and Kareem (2021). This contamination can result in a reduction of the soil strength and an increase in its compressibility and in subsequent an increase in lateral pile displacement and maximum bending moment.
Experimental and numerical study on the bearing capacity of single and groups of tapered and cylindrical piles in sand
Published in International Journal of Geotechnical Engineering, 2022
Ehsan Nasrollahzadeh, Nader Hataf
Piles are a kind of foundation which is used to transfer structural loading to deeper soil layers and to ensure structural safety. Piles are generally constructed in cylindrical shapes using different material and may be loaded axially or horizontally or under flexural moments. Tapered piles have usually a circular cross section which decreases from top to bottom and in comparison to cylindrical piles; they transfer a significant amount of load from their outer surface to adjacent soil. In the last 5 decades, numerous investigations have been conducted on tapered piles and their advantages to cylindrical piles have been proved, but as yet tapered piles are not considered as a widespread option in practice. Piles are commonly used in groups and therefore the pressure zone around piles skin and end overlap. If piles distances increase so that the pressure zone around piles did not overlap then each pile would act as a single pile, however, long piles distances are not practical.
Investigation the impacts of fuel oil contamination on the behaviour of passive piles group in clayey soils
Published in European Journal of Environmental and Civil Engineering, 2021
Mahdi O. Karkush, Zainab A. Kareem
Piles are slender elements used for transmitting the load from the superstructure through the water or through the weak compressible soil into stiffer layers or more compacted soil strata or into rocks (Tomlinson & Woodward, 2008). The laterally loaded piles can be classified into active piles and passive piles. The active pile is subjected to direct external horizontal force at the head of piles and then the load will transfer to the surrounding soil such as piles used to support offshore structures and transmission towers, while the passive pile is a pile subjected to the lateral thrust along its shaft resulted from the movement of surrounding soil and associated bending stress (Stewart, 1992). Karkush and Jafar (2015) investigated the effects of a nearby embankment on the behavior of pile foundation constructed in sandy soil. An incremental surcharge was applied at distances of 2.5 D, 5 D, and 10 D from the edge of the pile model, where D is the outer diameter of the model pile. Also, two embedded lengths of piles were investigated with 360 mm (rigid pile) and 420 mm (flexible pile). Based on the results of tests, it was concluded that increasing the distance between the embankment and pile reduces the effects of an embankment on the pile, also the axial loading on the piles reduces the effects of an embankment on the piles.