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可压缩性软土地基中,为了在确保基桩竖向承载力的前提下,有效降低地面堆载引起的负摩阻力对基桩承载力的影响,提出了一种现浇扩底楔形钢筋混凝土桩。简要介绍了扩底楔形桩的设计思路和施工工艺。基于FLAC3D有限差分软件,建立了扩底楔形群桩数值模型;通过针对具体模型试验实例的模拟分析,验证了本文所建立的数值模型的可靠性;继而研究了桩间距、楔形角、桩–土模量比、摩擦系数以及土层模量比等因素对扩底楔形群桩下拽力和下拽位移特性的影响,并与等截面桩进行了对比分析。研究结果表明,与等截面桩相比,楔形角的存在对降低桩顶下拽位移非常有效:小角度楔形角(0.4°～1.0°)对桩顶下拽位移量的减少率可以达到16%～20%。
In order to reduce the effect of negative friction caused by ground loading on the bearing capacity of piles under the premise of ensuring the vertical bearing capacity of the pile, a kind of cast-in-situ wedged reinforced concrete pile. Briefly introduces the design concept and construction technology of wedging piles. Based on FLAC3D finite difference software, a numerical model of wedged pile grouping is established. The reliability of the numerical model established in this paper is validated by simulation analysis of concrete model test examples. Then the relationship between pile spacing, wedge angle, pile-soil Modulus ratio, friction coefficient and soil modulus ratio on the drag force and drag-pull characteristics of the wedging group piles were compared with those of the equivalent section piles. The results show that the existence of wedge angle is very effective in reducing the downward displacement of piles when compared with that of the equivalent cross-section piles. The reduction rate of the downward displacement of piles can be reduced by 16% at the angle of 0.4 ° -1.0 °, ~ 20%.