Home / Standards / GB/T 41056-2021 GB/T 41056-2021 Active Full face tunnel boring machine—Double shield hard rock tunnel boring machine 全断面隧道掘进机 双护盾岩石隧道掘进机 Standard Type GBT ICS 91.220 CCS P97 Status 现行 Issue Date 2021-12-31 Implementation 2022-07-01 Responsible Dept 中国机械工业联合会 Drafting Unit N/A