A new look at the phenomenon of offshore pile plugging |
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| Authors: | Samuel G Paikowsky Robert V Whitman Mohsen M Baligh |
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| Institution: | 1. Department of Civil Engineering , University of Lowell , Lowell, MA, 01854;2. Department of Civil Engineering , Massachusetts Institute of Technology , Cambridge, MA, 02139 |
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| Abstract: | Abstract Open‐pipe piles are widely used for offshore structures. During the initial stage of installation, soil enters the pile at a rate equal to the pile penetration. As penetration continues, the inner soil cylinder may develop sufficient frictional resistance to prevent further soil intrusion, causing the pile to become plugged. The open‐ended pile then assumes the penetration characteristics of a closed‐ended pile. The mode of pile penetration significantly alters the soil‐pile interaction during and after installation. This affects the ultimate static bearing capacity (mainly in granular materials), the time‐dependent pile capacity (in clays), and the dynamic behavior and analysis of the piles. Following a summary demonstrating the effects of pile plugging, a review of the common view of offshore pile plugging is undertaken. The interpretation of plugging by referring to the average plug length has led to the erroneous conclusion that in most piles significant plugging action does not occur. Establishment of an analogy between soil samplers and open‐ended piles enabled correct identification of plugging by referring to the incremental changes in plug length. Examination of case histories of plugging of offshore piles revealed that beyond a certain penetration depth‐to‐diameter ratio, most piles are plugged. |
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| Keywords: | Offshore piles pile plugging open‐ended piles closed‐ended piles pile installation pile driving soil samplers |
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