管桩-塔脚机械型连接接头及其轴向性能分析

为解决传统桩-塔脚现浇型连接接头存在的受拉性能差、施工周期长等问题,提出了一种新型预应力混凝土高强管桩(precast high-strength concrete pile,PHC)管桩-塔脚机械型连接接头。先通过理论分析对新型连接接头中的圆筒和腹板最小厚度进行确定,再利用ABAQUS软件对其进行轴向性能有限元分析,并将其与传统现浇型连接接头进行对比。研究结果表明:当圆筒厚度为10 mm、腹板厚度为10 mm时,其能满足单项承载力要求、整体承载力要求及经济性要求。在受压荷载下,传统现浇型连接接头最终因塔脚全域受压屈曲而破坏;机械型连接接头最终因连接主体中的圆筒和腹板全域屈服而破坏,其可满足同型号管桩-塔脚的受压设计承载力要求,且可选择增大圆筒厚度和腹板厚度来提高整体受压承载力。在受拉荷载下,现浇型连接接头最终因预埋件中锚筋与混凝土锚固力不足而发生拔出破坏,拉伸位移均为预埋件刚体位移,连接接头具有很差的延性。机械型连接接头最终因啮合式连接接头中的连接销受拉变形过大而破坏,其受拉承载力远大于现浇型受拉承载力且具有较好的延性。

Pipe Pile-Tower Foot Mechanical Connection Joint and its Axial Performance Analysis

To solve the problems of poor tensile performance and long construction period of traditional pile-tower foot cast-in-place joint, a new type of Precast high-strength concrete pile (PHC) pile-tower foot mechanical joint is proposed. The minimum thickness of cylinder and web in the new joint is determined by theoretical analysis, and then finite element analysis of axial performance is carried out by ABAQUS and compared with the traditional cast-in-place joint. The results show that when the thickness of the cylinder is 10 mm and the thickness of the web is 10 mm, it can meet the single load capacity requirement, the overall load capacity requirement and the economic requirement. Under the compressive load, the traditional cast-in-place joint will be damaged by buckling in the whole area of the tower foot; the mechanical joint will be damaged by buckling in the whole area of the cylinder and web in the main body of the joint, which can meet the compressive design bearing capacity requirements of the same type of pipe pile - tower foot, and can choose to increase the thickness of the cylinder and web to improve the overall compressive bearing capacity. Under the tensile load, the cast-in-place joint eventually breaks due to the lack of anchoring force between the anchor bar and concrete in the pre-built parts, and the tensile displacement is all rigid displacement of the pre-built parts, and the joint has very poor ductility. The mechanical connection joint is eventually damaged by the excessive tensile deformation of the connection pin in the engagement type connection joint, and its tensile bearing capacity is much larger than the cast-in-place tensile bearing capacity and has better ductility.