利用空气冲旋钻井技术进行钻进时,易出现钻齿脱落、折断以及磨损严重等失效问题。针对该问题,应用岩石力学试验机和S H PB试验装置,开展了花岗岩动态劈裂拉伸、单轴压缩和围压下的压缩性试验,为数值模拟提供了必要的岩石材料模型参数。数值模拟选用 H-J-C动态本构模型,结合试验结果确定了材料模型参数,选择花岗岩的拉应变作为失效准则。在此基础上,对钻齿的齿形参数和破岩的钻齿侵入深度、破碎体积进行了数值模拟。研究表明,相同工况下锥形中心齿的破岩效率最高,边齿角度取30°可显著提高岩石的破碎体积。在此基础上,对齿面布齿进行选配研究,发现“中心球形齿+周围锥形齿”的破岩效率最高,“中心球形齿+周围球形齿”组合的破岩效率最低。
To investigate frequent failures of drill bit teeth in air hammer drilling like teeth falling ,breaking and severe wear ,laboratory experiments of dynamic splitting tensile ,uniaxial and triaxial compression and compression with granite samples were conducted with the SHPB and material test system to obtain mechanical properties of the rock for numerical simulation .H-J-C dynamic constitutive model was adopted for in numerical simulation ,the material model parameters were determined from experiment ,and tensile strength of granite was selected as failure criterion .Drill bit tooth parameters ,the bit teeth sinking depth ,crushing volume were simulated numerically ,which showed that the cone tooth has the highest efficiency in rock breaking under the same conditions and heel tooth in 30° can increase the rock crushing volume significantly .In addition ,the configuration of tooth surface was examined ,which showed that the pat-tern of“ball teeth in the middle and cone teeth in the peripheral”has highest rock breaking efficiency ,but the pattern of“ball teeth in the middle and peripheral”has lowest in rock breaking efficiency .