TBM双滚刀间距及入岩次序对破岩效果影响研究

TBM滚刀位置布置对于TBM掘进效率极为重要,为研究TBM双滚刀间距及入岩次序对破岩效果的影响,利用二维离散元颗粒流软件(PFC2D)建立TBM双滚刀破岩模型,对TBM破岩过程中裂纹的扩展、岩石破坏形式、岩片面积、破岩比能、滚刀推力等变化进行了模拟分析。结果表明:(1)滚刀间距对于破岩效果具有较为明显的影响。间距过小时,滚刀间形成的岩片过于粉碎,滚刀间距过大,相邻滚刀形成的裂纹无法贯通,滚刀之间形成岩脊。间距不同破岩比能不同,存在最优滚刀间距现象。(2)滚刀入岩次序影响破岩效果。前后滚刀对于岩石的损伤深度和范围不同,同时破岩时左右滚刀所需垂直力较为接近,顺次破岩时后滚刀所需垂直力平均值小于前滚刀。相同滚刀间距下顺次破岩比能高于同时破岩时的比能,破岩效果将低于同时破岩情况。研究成果可为TBM滚刀布置设计提供一定参考。

Study on influencesfrom spacing between dual-disc cutters and rock-penetrating sequence of TBM on rock-breaking effect

In order to study the influences from the spacing between the dual-disc cutters of TBM and the rock-penetratingsequence on rock-breaking effect，a rock-breaking model for the TBM with dual-disc cutters is established with the 2 － D particle flow code ( PFC2D) ，and then the changes of fissure expansion，rock failure mode，rock-fragment area，rock-breaking specific energy，disc cutter thrust，etc. during the rock-breaking process of TBM are simulated. The result shows that ( 1) the spacing between the disc cutters has a more significant influence on the rock-breaking effect. When the spacing is too small，the rockfragments formed between the disc cutters are over-crushed，while if the spacing is too large，the fissures formed by the adjoining disc cutters cannot be broken through and a rock ridge is to be formed between both of them. If the spacing is different，the rockbreaking specific energy is different too，thus a phenomenon of optimal spacing between the disc cutters exists there. ( 2) The rock penetrating sequence of the disc cutters influences the rock-breaking effect. The rock damage depths and ranges of the front and the rear disc cutters are different，while the vertical forces necessary for the left and right cutters are more approximate during rock-breaking and the mean value of the vertical force necessary for the rear disc cutter is less than that for the front one during the rock-breaking in sequence. The rock-breaking specific energy of the rock-breaking in sequence is higher than that of the simultaneous rock-breaking under the condition of the same spacing between disc cutters，but the rock-breaking effect is to be lower than that from the simultaneous rock-breaking. The study result can provide a certain reference for the design of the layout of disc cutters for TBM.