围压下掘进机多滚刀顺次破岩机理数值模拟研究

基于统计力学与细观损伤数值模型,运用RFPA^2D建立三把滚刀顺次侵入岩石的计算模型,并展开系列数值试验,模拟了岩石在不同围压、不同加刀次序下裂纹萌生、扩展以及破碎的全过程,并从能量的角度出发对刀间距的优化问题展开了探讨。研究结果表明,滚刀相位角的存在对岩石的破碎模式和破碎效率有着重要的影响;滚刀顺次加刀优于同时加刀;围压增大,裂纹向深部扩展能力降低。相同围压下顺次加载时存在最优刀间距。同时加载时,随着围压的增加,最优刀间距逐渐增加。研究结果可为地下工程岩石破碎理论与隧道掘进机刀盘布置提供依据。

Numerical Study of the Rock Fragmentation by Tunnel Borer Cutters under Confining Pressure

Based on statistical mechanics and micromechanical damage theory, a numerical code RFPA^2D was used to investigate the rock fragmentation by three tunnel borer cutters applied one after another. The fracturing process of the rock specimens with different confining pressure and cutting sequence was simulated. The effect of confining pressure and the bit cutting sequence was discussed from the view of consumed energy. To apply the cutters one by one with a certain phase angle is better than to apply them at the same time. It was harder for the cracks to coalescence as the confining pressure increased. There exists an optimum cutter spacing to obtain the smallest specific energy. The optimum cutter spacing increased when the confining pressure increased. The results can be useful to understand the interaction of rock and cutters and the cutter spacing design in tunnel engineering.