Investigations of material discharge caused by groundwater flow during the installation of bored piles
Investigations of material discharge caused by groundwater flow during the installation of bored piles
Bored piles are often installed below the groundwater level. During installation, it has to be ensured that groundwater flow does not lead to a reduction of the pile integrity from pouring until the concrete has stiffened. The European Standard EN 1536, the German Recommendations on Piling “EA-Pfähle” (2013) and international guidelines refer to possible problems resulting from groundwater flow. However, no information is given as to which groundwater flow velocity is critical in which ground. In order to be able to estimate the risk of cement particle removal or redistribution, model piles were installed with the tremie method at the University of Wuppertal in a joint research project. These piles were exposed to several water flow velocities during installation. The created flow velocities were substantially higher than the groundwater flow velocities which occur in field. In a first series of tests, the focus was on test piles made of tremie concrete which were placed in sandy soils. In a second series of tests, a variation of concrete mix design and surrounding soil was performed to obtain a more general statement. In summary, it could be shown that no critical flow velocity could be reached which lead to a “washing-out effect” of cement on the pile surface within the scope of both series of tests.
H. Nissen; Claudia Fierenkothen; E. Dornecker; Markus Herten
18th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE2024)
D - Current and new construction methods
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