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负摩阻力引起的基桩下拽力和下拽位移是桩基础设计中必须考虑的重要问题之一,楔形桩中的倒楔形角是一种有效减少基桩下拽力和下拽位移的结构形式;但是针对楔形角在减少负摩阻力效果方面的研究却相对较少。结合工程实例,建立单、群桩负摩阻力特性分析的三维数值模型,并通过与现场试验结果和已有文献分析结果的对比分析,验证所建模型的准确性和可靠性。对比分析4种不同楔形角组合形式对基桩负摩阻力的减少效率以及是否考虑土体固结形式对基桩负摩阻力特性的影响规律。研究结果表明,桩体上部分楔形角对基桩负摩阻力特性影响较显著;桩体下部分楔形角的影响相对不明显;小角度范围内,楔形角增加1度,最大基桩下拽力减少约20%。
The negative drag force and the pull-down displacement of piles are one of the most important issues that must be considered in pile foundation design. The inverted wedge angle in wedge piles is a kind of structure that can effectively reduce the drag force and pull-down displacement of piles. However, the research on the effect of wedge angle on reducing negative skin friction is relatively few. Combined with engineering examples, a three-dimensional numerical model of single-group and group-pile negative skin friction characteristics was established. The accuracy and reliability of the proposed model were verified by comparison with the field test results and the existing literature analysis results. The effects of four kinds of wedge angle combinations on the negative friction reduction of foundation piles and whether the influence of soil consolidation forms on the negative skin friction characteristics of the foundation piles are analyzed. The results show that the influence of the wedging angle of the lower part of the pile is not obvious. The wedge angle increases by 1 degree and the maximum piling drag Reduce by about 20%.