Abstract: The material constitutive law of SFRC was established by the 3-point bending test on a notched beam, and plastic axial tensile strength was obtained. The full-scale SFRC segments with different steel fiber content and reinforcement configuration were used in the jacking test, and the failure process curve of shield segment under the jacking force was obtained. The failure mode, cracking load, initial crack location and crack propagation path of unreinforced and less reinforced SFRC segments were studied. Through numerical simulation, the mechanical response law of the jacking test was simulated, and the corresponding relationship between jacking load and segment stress was established. Then, taking the stress reaching the plastic axial tensile strength as the cracking criterion, the jacking control load obtained from the test was verified. The research results show that both unreinforced and less reinforced SFRC segments can meet the bearing capacity requirements under the reciprocating action of common construction jacking forces. Under the action of jacking load, the initial failure position of segment is in the tensile stress area on the opposite side of the loading point. The reinforcement configuration has a significant effect on the crack resistance toughness of SFRC segments under the action of jacking load. The ability of crack control of unreinforced SFRC segment is poor, so the crack load should be taken as the control load under the jacking condition.

Key words: tunnel engineering; steel fibre reinforced concrete; plastic axial tensile strength; jacking test; cracking and failure law; jacking control load

摘要： 以开口梁三点弯曲试验结果为基础，建立钢纤维混凝土材料本构模型，得到其塑性轴拉强度。选用不同钢纤维掺量和钢筋配置的全尺寸钢纤维混凝土管片进行顶推试验，得到管片在顶推力作用下的破坏过程曲线，对无筋和少筋钢纤维混凝土管片的破坏形式、开裂荷载、初裂位置以及裂缝展开路径进行了研究。采用数值仿真模拟了顶推试验所展现的力学响应规律，建立了顶推荷载和管片应力的对应关系，进而以应力达到塑性轴拉强度为开裂判据，对试验得到的顶推控制荷载进行了验证。研究结果表明：无筋和少筋钢纤维混凝土管片均可满足常用施工顶推力往复作用下的承载力要求；在顶推荷载作用下，管片的初始破坏位置均在加载点对侧的拉应力区；钢筋配置方式对顶推荷载作用下的钢纤维混凝土管片抗裂韧性影响显著；无筋钢纤维混凝土管片控制裂缝展开能力较差，应以开裂荷载为其顶推工况的控制荷载。

关键词: 隧道工程；钢纤维混凝土；塑性轴拉强度；顶推试验；开裂及破坏规律；顶推控制荷载