全断面岩石掘进机滚刀最优刀间距计算公式研究

基于剪切与张拉破岩机制，提出拉剪综合失效机制假设；建立了非协同切削与协同切削体积模型，推导了协同切削模式的滚刀比能耗理论模型；通过离散元仿真得到滚刀侵入岩石裂纹长度与贯入度的映射关系；推导出滚刀最优刀间距理论公式；以全断面岩石掘进机（TBM）回转切削试验台为基础，水泥模拟料为切削对象，通过多次压痕试验得到滚刀贯入度和岩石裂纹长度的趋势曲线，验证了仿真结果；通过滚刀滚动破岩进行了12组不同贯入度与刀间距的物理切削试验，统计滚刀做功与岩石破碎体积，拟合得到比能耗关系曲线，验证了最优刀间距理论公式的结论。研究表明：TBM滚刀最优刀间距计算公式综合考虑了岩石特性与滚刀结构特性，适应性较广泛；刀间距超过滚刀协同工作距离时，滚刀破岩以剪切破碎为主；刀间距小于2倍岩石裂纹长度时，张拉破碎的影响更加明显；随着贯入度的增加，最优刀间距逐渐增大，而最优滚刀间距S与贯入度P之比（S/P）值则逐渐减小。

Study of calculation equation of TBM disc cutter optimal spacing

Based on tensile and shear failure mechanisms of rock breakage, a synthetic failure hypothesis has been proposed. With the establishment of the non-collaborative and collaborative cutting volume model, a theoretical model is deduced for the specific energy of tunnel boring machine (TBM) cutters working in the collaborative cutting mode. The relationship between the crack length and penetration is established by a discrete element model (DEM). A theoretical formula of optimal cutter spacing is then derived by the fitting method. Additionally, indentation experiments are conducted the cement simulation material as cutting objects using the TBM rotary cutting test platform. The relationship between the hob penetration and the crack length of the rock is obtained, and then the simulation results are verified by experimental results. The broken-rock volume is counted through 12 cutting experiments with different penetrations and spacings between cutters. Then the specific energy consumption fitting curve is obtained, which verifies the conclusion of optimal cutting spacing equation. The research results show that the characteristics of rock properties and the structure of the hob are comprehensively considered in the optimal cutter-spacing calculation formula of the full-face rock TBM, which potentially has wide applications. When the cutting spacing is greater than the collaborative spacing, the shear failure mechanism plays a dominant role in rock-breaking process. However, when the cutting spacing is less than the twice lateral crack length, the tensile failure mechanism has more significant effects on rock breakage. As the penetration increases, the optimal spacing increases while the optimal S/P decreases.