大口径混凝土顶管具有脆性大、易开裂、运输吊装难等问题,高性能纤维混凝土(HPFRC)的出现为解决上述问题提供了可能,但目前相关研究匮乏,工程应用困难。基于国内外高性能混凝土的研究成果,提出HPFRC顶管配筋设计方法,并基于三点加载足尺试验对HPFRC顶管承载能力和配筋方法进行研究。结果表明:HPFRC顶管在配筋设计时,应考虑钢纤维的作用,不可忽视混凝土受拉区的影响;HPFRC顶管采用C150强度等级,与C50混凝土顶管相比,能有效减小混凝土壁厚和配筋量,配筋量基本由最小配筋率控制;HPFRC顶管在足尺试验中,抗裂性能较好,结构位移-荷载曲线呈现强化特征,体现了良好的延性;试验管节外径2.86 m,壁厚仅180 mm,较C50混凝土顶管的壁厚和配筋量均减小20%以上,达到III级管水平。

Large-diameter concrete pipe jacking faces issues of brittleness, susceptibility to cracking, and difficulties in transportation and hoisting. The emergence of high-performance fiber-reinforced concrete (HPFRC) offers a new possibility for addressing the above problems. However, the related research is scarce, and the engineering applications are still challenging. Based on the research results of high-performance concrete at home and abroad, this paper puts forward the design method of HPFRC pipe jacking reinforcement, and studies the bearing capacity and reinforcement method of HPFRC pipe jacking based on three-point loading full-scale test. The research shows that the effect of steel fiber should be considered in the reinforcement design of HPFRC jacking pipe, and the influence of concrete tensile zone should not be ignored. Compared with C50 concrete pipe jacking, HPFRC pipe jacking can effectively reduce the wall thickness and reinforcement amount of concrete, and the reinforcement amount is basically controlled by the minimum reinforcement ratio. In the full-scale test, HPFRC jacking pipes exhibited excellent crack resistance, and their load-displacement curves demonstrated strain-hardening behavior, indicating superior ductility. The outer diameter of the test pipe section is 2.86 m, and the wall thickness is only 180 mm. Compared with the wall thickness and reinforcement of the C50 concrete jacking pipe, the wall thickness and reinforcement are reduced by more than 20%, reaching the level of Class III pipe.