考虑桩顶与土表加载顺序的桩基负摩阻力模型试验研究
doi: 10.13204/j.gyjz201506020
MODEL TESTS ON NEGATIVE SKIN FRICTION ON PILES CONSIDERING SEQUENCE LOADED ON PILE HEAD AND SURCHARGE AROUND PILES
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摘要: 对于承受负摩阻力的桩基,桩顶和土表的承载一般存在先后的次序,但针对承载顺序对桩身负摩阻力影响的研究相对匮乏。通过开展不同加载顺序下砂土中单桩负摩阻力模型试验,测得了不同加载作用下桩身轴力、桩顶位移以及土体分层沉降。研究结果表明:砂土中加载顺序对桩基负摩阻力具有明显影响。先施加土表荷载的组次较先施加桩顶荷载的组次,桩身中性点位置更靠近桩底。先施加土表荷载后,桩顶荷载作用下的桩顶沉降明显小于先施加桩顶荷载的情况,而不同加载顺序下,土表荷载作用下的桩顶沉降的变化规律基本一致,且桩顶沉降增长随土面荷载趋缓。Abstract: As for piles under negative skin friction,there exists a sequence loaded on pile head and surcharge around piles. However,the influence of the loaded sequence on negative skin friction is less studied. Aiming at researching the influence of the loaded sequence,the indoor model tests for negative skin friction on single pile in sand were carried out. The axial force of pile shaft,settlement of pile top and each soil layer were measured. The results showed that the influences of the loaded sequence were obvious on the negative skin friction of the pile in sand. When the surcharge around piles were loaded first,the neutral plane were closer to piles tips. Settlement of piles loaded on surcharge around piles first were significantly smaller than that of piles loaded on the tops first. The pile head settlements under the action of surcharge load were basically identical with the different loaded sequence,and the increase amplitudes of pile head settlements slowed down gradually with the increasing of surcharge load around piles.
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Key words:
- loaded sequence /
- pile /
- negative skin friction /
- model test /
- neutral plane /
- dragload
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