This paper studies the bearing characteristics of different types of cast-in-place piles, with or without grouting, based on a bridge construction in Wuqi-Dingbian Expressway. Manual digging piles (MDPs), rotary drilling piles (RDPs), and impact drilling piles (IDPs) are investigated, and an in-situ static load test is carried out on each type of hole-forming method. The post-grouting results show that the grouting quantity of RDP is the largest, which is 3.15 t, and the IDP is the smallest, which is 1.5 t. According to the static load test, the ultimate bearing capacity of IDP is the largest and increases the most after grouting, while MDP has the smallest increase in ultimate bearing capacity. The IDP also displays the most significant increase of pile side resistance and largest proportion of pile end resistance to the total load, showing obvious characteristics of the end bearing friction pile. The calculation method of ultimate bearing capacity of the post-grouting pile recommended by Chinese code is also verified in this work, illustrating that it is necessary to study the upper return height of slurry in post-grouting. The obtained research results provide an increased understanding of the post-grouting mechanism and reference for the rational calculation of the bearing capacity of post-grouting pile and hole-forming method selection.

本文基于吴起-定边高速公路的桥梁工程，研究了不同类型的有无灌浆灌注桩的承载特性。对手动挖掘桩（MDP），旋转钻桩（RDP）和冲击钻桩（IDP）进行了研究，并对每种类型的成孔方法进行了现场静载荷测试。注浆后结果表明，RDP注浆量最大，为3.15t，IDP注浆量最小，为1.5t。根据静载荷试验，灌浆后IDP的极限承载力最大，增加最多，而MDP的极限承载力增长最小。IDP还显示出桩侧阻力增加最明显，而桩端阻力占总载荷的比例最大，表现出端承摩擦桩的明显特征。本文还验证了中文规范推荐的后注浆桩极限承载力的计算方法，说明有必要研究后注浆的上部回浆高度。所得研究成果为后注浆机理的理解提供了更多的依据，为后注浆桩承载力的合理计算和成孔方法的选择提供了参考。