TBM滚刀破岩过程的声发射特征

Acoustic Emission Characteristics of Rock Fragmented by TBM Cutter

为了研究隧道掘进机(tunnel boring machine,TBM)滚刀破岩试验过程中的声发射特征,采用北京工业大学自主研制的大型机械破岩试验平台并结合声发射监测技术进行试验。试验中利用常截面盘形滚刀,对北山花岗岩进行不同贯入度下的线性切割破岩试验,并采集试验过程中的声发射信号。分析声发射能率与能量特征,对信号进行小波去噪处理后,利用Geiger算法给出岩石损伤的声发射定位。研究发现:声发射能率与滚刀法向力具有相近的变化趋势;声发射能量随贯入度增大而增加,可用于表征滚刀切削岩石所消耗的能量;声发射定位点大致描述损伤的分布范围,较好地反映出岩石在滚刀切割作用下损伤积累到形成岩片的过程。

To study acoustic emission(AE)characteristics of rock fragmentationed by tunnel boring machine(TBM)cutter,a mechanical rock fragmentation experimental platform of Beijing University of Technology was used,and the acoustic emission system was employed for real-time monitoring.In the experiment,the disc cutter with a constant cross section was used and the test granite rock sample was taken from Beishan,Gansu Province of China.A series of tests with different penetrations were conducted and AE signal was collected during the process.AE energy and AE energy rate were analyzed,and AE location calculated with Geiger algorithm was demonstrated after signal de-noising using wavelet transform.Results show that AE energy rate has the similar change trend with the normal force.AE energy increases with the growth of penetration,and can be applied to representation of the energy consumed in rock fragmentation.An approximate description of damage zone that was obtained by AE location shows the whole process of crack accumulation and propagation during rock fragmentation.