不同双向侧压作用下TBM滚刀侵入破岩特征及效率研究

A study on rock breaking characteristics and efficiency with TBM cutters in a biaxial state

为研究不同双向围压条件下TBM滚刀破岩特征及效率,基于真三轴试验平台进行了滚刀顺次侵入试验,并利用形貌扫描仪对滚刀侵入后形成的破碎坑形态及体积进行了分析。结合裂纹发育及滚刀破岩效率分析,结果表明:当较小围压(Sig_1)一定时,随着围压差的增大,虽然TBM滚刀侵入过程中的侵入能量逐渐增大,但其形成的破碎坑体积也随之增大,进而导致其破岩效率的增大。当较大围压(Sig_2)一定时,随着较小围压的增大,其侵入能量也随之增大,但其破碎坑体积随之减小,进而导致其破岩效率降低。

To investigate rock breaking mechanisms induced by cutters of tunnel boring machine （TBM） under a biaxial state, TBM indentation tests were conducted on granite specimens using a triaxial testing platform. Then, detailed morphological measurement was carried out to analyze the morphology and volume of the fractured surface using a surface profilometer. It is found that the increase of differential stress results in the increase of consumed energies, the growth of groove volumes and the efficiency of indentation when the Sig_l （i.e., the smaller confining pressure） was fixed. The energy of indentations increases as the differential stress decreases, but the groove volumes are decreased, and thus the indentation efficiency is restrained by the decline of the differential stress when the Sig_2 （i.e., the bigger confining pressure） was fiXed.