钢-混凝土复合桩轴压试验及力学性能分析

Axial Compression Test and Mechanical Property Analysis of Steel-Concrete Composite Pile

为提高钢管桩在浅覆盖层区的承载能力,采用钢管桩钻芯内嵌工字钢的桩基锚固措施,以广东清西大桥临时钢栈桥为工程背景,设计并进行钢-混凝土复合桩模型试验,分析了外钢管应变、内嵌工字钢的轴力与侧摩阻力、复合桩的轴心受压性能与承载机理,提出了复合桩承载力计算公式。试验结果表明:在轴压荷载作用下,钢管、核心混凝土与内嵌工字钢三者协同受力,荷载传递性能良好,提高了复合桩的承载能力;内嵌工字钢在钢混段与嵌固段交界处出现轴力集中现象;破坏特征为内嵌工字钢屈服后钢管表面发生外鼓变形破坏,钢管与核心混凝土出现相对滑移并分离。选取更高规格工字钢或增加工字钢的嵌入根数,有利于提高复合桩的承载力,承载力公式计算结果与试验结果吻合较好。

To improve the bearing capacity of the steel pipe pile in the shallow overburden zone,the pile foundation anchoring measures of the steel plate pile core embedded with the I-beam are adopted.Based on the temporary steel trestle bridge of Qingxi Bridge in Guangdong Province,the steel-concrete composite pile model test was designed and carried out.The axial strain of the outer steel tube,the axial force and side friction resistance of the embedded I-beam,and the axial compression performance of the composite pile were analyzed.With the bearing mechanism,the calculation formula of bearing capacity of composite pile was proposed.The test results show that under the axial compression load,the steel tube,core concrete and embedded I-beam are co-stressed,the load transfer performance is good,and the bearing capacity of the composite pile is effectively improved;the embedded I-beam is in the steel mixing section.The axial force concentration occurs at the junction with the embedded section;the failure characteristic is that the outer drum deforms and deforms after the yield of the inlaid I-steel steel,and the steel pipe and the core concrete appear to be relatively slipped and separated.Selecting the higher specification I-beam or increasing the number of embedded I-beams is beneficial to improve the bearing capacity of the composite pile.The calculation results of the bearing capacity formula agree well with the experimental results.