【摘要】 长径比对组合后压浆钻孔灌注桩的承载性状有着重要影响，基于宁梁高速京杭运河特大桥试桩静载数据，分析组合后压浆、长径比和桩端持力层对钻孔灌注桩荷载传递特性的影响。在此基础上，基于荷载传递法和球面扩散理论，构建了综合考虑长径比和桩端扩大头影响的组合后压浆桩沉降计算方法，通过工程实例验证了方法的合理性。结果表明：组合后压浆工艺在实现桩长优化的同时，可以有效提升灌注桩承载力；组合后压浆桩的荷载传递特性受长径比和持力层种类影响大，不同长径比组合后压浆桩的桩侧荷载传递曲线初始斜率最大相差幅度达380%;相较于已有预测方法，所提计算方法能较好地预估不同长径比组合后压浆桩的荷载沉降特性，在预估结果偏安全的情况下，为组合后压浆桩的科学优化设计提供参考。更多还原

【Abstract】 The length-diameter ratio has important influences on the bearing behavior of combined grouting bored piles. Based on the field test data of bored piles in the Jinghang Grand Canal Bridge on Ningliang Expressway, the effects of combined grouting, length-diameter ratio and bearing layer on the load transfer characteristics of bored piles were analyzed. On this basis, the calculation method for settlement for combined grouting bored piles based on the load transfer method and spherical permeation grouting theory was established, considering the influences of length-diameter ratio and an enlarged pile tip, and the rationality of the calculation method was varified by an engineering example. The results show that combined grouting effectively improves the ultimate bearing capacity of bored piles under the premise of pile length optimization. The load transfer characteristics of the combined grouting bored pile are greatly affected by the length-diameter ratio and the type of bearing layer. The initial slope of the side load transfer curve of the combined grouting bored pile with different length-diameter ratios can vary by up to 380%. Compared with existing prediction methods, the proposed calculation method can better predict the actual load-settlement characteristics of the combined grouting bored pile, which provides a reference for the scientific optimization and design of the combined grouting bored pile while ensuring the safety of the prediction results.更多还原