Abstract: Concrete strength grade, thickness of steel pipe, diameter of the piles and yield strength of steel are the main factors to affect the bending strength of micro CFST members. In order to research the influence of the above four factors on the bending properties of micro CFST members, the finite element software ABAQUS was adopted and the numerical simulation was carried out. The research results show that: the bending strength of micro CFST members is increased with the increase of concrete strength grade, but the growth rate gradually decreases; the bending strength of micro CFST members is increased with the increase of the thickness of steel pipe, and their relation is almost linearly; the bending strength of micro CFST members is increased with the increase of diameter of the piles and the growth rate is increased with the increase of diameter of the piles; the bending strength of micro CFST members is increased with the increase of yield strength of steels. In addition, based on the results of finite element numerical calculation, the expression of ultimate flexural capacity of micro CFST members was proposed finally, and compared with the experimental results, they corresponded well. By comparing with the norms, the calculation method of flexural bearing capacity proposed in this paper is more suitable for micro CFST members.

Key words: geotechnical engineering, micro CFST members, bending strength, numerical simulation, concrete damageplasticity

摘要： 影响微型钢管混凝土构件抗弯性能的主要因素有混凝土强度等级、钢管壁厚、桩径、钢材屈服强度等4个因素，为了研究这4个因素对微型钢管混凝 土构件抗弯性能的影响，采用有限元软件ABAQUS，通过数值模拟的手段对其进行研究。研究结果表明：微型钢管混凝土构件的抗弯强度随着混凝土强度等 级的提高不断增大，但是增幅在逐渐减小；微型钢管混凝土构件的抗弯强度随钢管壁厚的增加而增加，两者几乎呈线性相关；微型钢管混凝土构件的抗弯 强度随桩径的增大而增大，且增长速率随着桩径的增大逐渐在增大；微型钢管混凝土构件的抗弯强度随钢材屈服强度的增大而增大。另外，基于有限元数 值计算结果，最后提出了微型钢管混凝土构件的极限抗弯承载力表达式，与试验结果进行对比，两者吻合良好。通过与各规程进行对比，提出的抗弯承载 力计算方法用于微型钢管混凝土构件更合适。

关键词: 岩土工程, 微型钢管混凝土构件, 抗弯强度, 数值模拟, 混凝土损伤塑性