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首页> 外文期刊>Tunnelling and underground space technology >Numerical study of the effect of confining pressure on the rock breakage efficiency and fragment size distribution of a TBM cutter using a coupled FEM-DEM method
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Numerical study of the effect of confining pressure on the rock breakage efficiency and fragment size distribution of a TBM cutter using a coupled FEM-DEM method

机译：有限元-DEM耦合法研究围压对TBM刀具破岩效率和碎块尺寸分布的影响

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Confining pressure is an important factor that affects the rock breakage efficiency of Tunnel Boring Machines (TBMs). This study analyses the influence of the confining pressure on the rock breakage process, rock breakage efficiency and fragmentation distribution after crushing using a coupled FEM-DEM method. First, the parameters of the rock numerical model are calibrated using numerical uniaxial compression tests and Brazilian tests. Second, the rock breakage by the cutter is simulated under different confining pressures, and the influence of the confining pressure on the rock breakage process is determined. Third, using a post-processing program developed for extracting the induced fragments, the distribution of fragments after rock fragmentation is obtained, which accurately provides the fractured area of the rock to determine the variation of the specific energy (SE) with confining pressure. Finally, the equivalent length distributions of the fragments are analysed using the fractal method. The results show that the confining pressure has a significant inhibitory effect on the propagation of median cracks. The angle of the lateral crack increases with increasing confining pressure, and the length of the crack first increases and then decreases. The maximum normal force and the maximum indentation distance also increase first and then decrease with increasing confining pressure. The SE first increases with increasing confining pressure; however, when the confining pressure reaches the first critical value, the SE begins to decrease with increasing confining pressure and then continues to increase after the confining pressure reaches the second critical value. The variation of the fractal dimension with the confining pressure is similar to the variation of the SE with the confining pressure.
机译：围压是影响隧道掘进机（TBM）碎石效率的重要因素。这项研究使用耦合有限元-DEM方法分析了围压对破碎过程，破碎效率和破碎后碎石分布的影响。首先，使用数值单轴压缩试验和巴西试验对岩石数值模型的参数进行校准。其次，模拟了刀具在不同围压下的破岩情况，确定了围压对破岩过程的影响。第三，使用开发用于提取诱发碎片的后处理程序，获得岩石碎裂后碎片的分布，从而准确地提供岩石的破裂区域，以确定围压下比能量（SE）的变化。最后，使用分形方法分析片段的等效长度分布。结果表明，围压对正中裂纹的扩展具有显着的抑制作用。横向裂缝的角度随围压的增加而增加，并且裂缝的长度先增大然后减小。最大法向力和最大压痕距离也随围压的增加先增大，然后减小。 SE随着围压的增加而首先增加。但是，当围压达到第一临界值时，SE随围压的增加而开始减小，然后在围压达到第二临界值后继续增大。分形尺寸随围压的变化与SE随围压的变化相似。

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