射流联合盾构切削钢筋混凝土仿真与试验
Simulation and experiment on cutting reinforced concrete with jet combined shield method
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摘要: 针对传统盾构刀具直接切削钢筋混凝土所产生的弊端,进行磨料水射流联合盾构刀具切削钢筋混凝土研究。通过仿真和试验探究了磨料水射流在不同横移速度下对钢筋和素混凝土的切削效果和切割机理并确定了切割钢筋混凝土的最佳横移速度。研究结果表明:磨料水射流对钢筋和混凝土的切割机理存在差异性,水射粒子对钢筋的切割贡献十分有限;混凝土的切口深度和宽度大于钢筋,对横移速度变化的敏感性小于钢筋;在高横移速度下混凝土切口损伤宽度得到扩大但并不显著、钢筋出现切割残余;切割深度随着横移速度的增加而减小,下降速度由陡变缓;10 mm/min的横移速度较好满足切割C55钢筋混凝土的要求。基于前期研究成果开展模拟盾构切削试验,分析了磨料水射流联合盾构刀具破除C55钢筋混凝土的效果、刀具损伤和参数特征。试验结果表明:磨料水射流联合盾构刀具切削能有效解决盾构刀具直接切削所产生的钢筋缠绕问题,减少了刀具损伤,控制了扭矩峰值。Abstract: The research of abrasive water jet combined with shield cutting tools in the cutting of reinforced concrete is carried out because of the disadvantages of the traditional shield cutting tools in the direct cutting of reinforced concrete. The cutting effect and mechanism of abrasive water jet on reinforced concrete and plain concrete under different moving speed are explored, and the best moving speed of cutting reinforced concrete is determined through simulation and experiment. The results show that the cutting mechanism of abrasive water jet is different from that of concrete. The contribution of water jet particles to steel cutting is limited. The depth and width of concrete incision are greater than those of steel. The sensitivity of concrete to the change of transverse velocity is less than that of steel bar. The damage width of concrete notch is enlarged but not obvious, and the cutting residues occur in the reinforcement under high transverse velocity. The cutting depth decreases with the increase of the traverse speed. The descending speed slows down. The transverse velocity of 10 mm/min can meet the requirements of cutting C55 reinforced concrete. The cutting experiment of the simulation shield machine is carried out based on the previous research results. The effect, tool damage and parameter characteristics of the abrasive water jet combined shield machine tool to break C55 reinforced concrete are analyzed, and the results are compared with those of the shell knife direct cutting. The results show that the abrasive water jet combined with shield cutter cutting can effectively solve the problem of steel winding caused by the direct cutting of shield cutter, reduce the cutter damage and control the peak torque.