Numerical analysis on negative skin friction of pile group with cap
| Autor: | HAO-SHIANG HSU, 許皓翔 |
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| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Since 1960, negative skin friction (NSF) is one of the common problems in the design of pile foundations. In the past, several literatures reports can be found regarding the NSF on single pile and group piles in a compressible clay. NSF induces additional vertical load on the pile and pile settlement. it must to reduce the safety of the structure. The objective of research is to investigate the dragload and downdrag on friction and end-bearing single pile with the finite different package FLAC3D. The simulation results of FLAC3D were compared with the results of FLAC2D to examine their difference. Group piles analysis considers the influence of various parameters including pile group configuration, position of piles in the group, surface loading and pile cap. The group effect are significantly influenced axial force and soil settlement. Finally, using FLAC3D to simulate the NSF of bridge foundations at High Speed Railway when the ground water was dropdown from the ground table to the lower elevation. Based on the results and the comparisons from the analysis for group piles the following conclusions can be drawn: (1)Group effect causes reduction of soil settlement and dragload significantly on pile groups for the relatively small surcharge. The maximum reduction of dragload is obtained in central pile. (2)The magnitude of surface loading increases the group effect decreases. (3) Additional vertical load on friction corner piles was caused by fix-head cap.(4) In the THSR analysis case, when the ground water table was dropdown from the ground table to the depth of 52 meters, NSF would be limit stated to cause the maximum dragload on group piles. It might reduce the bearing capacity of the pile foundations seriously. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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