新意法在软弱围岩超大断面隧道掘进施工中的应用

The Application of NITM in Full Face Excavation for Tunnel of Super-Large Cross-Section through Weak Rock

摘要: 在软弱围岩的介质环境中，采用新意法可以实现大断面隧道的全断面开挖。为了探讨新意法应用的关键技术，依托于浙江某山岭隧道工程，选取了20米作为试验段，进行了新意法技术的应用试验研究。本项试验研究的结果表明：实施新意法的关键在于掌子面超前岩体的加固、掌子面挤出变形的实时量测和实时施工反馈。试验研究证明采用玻璃纤维锚杆对掌子面超前岩体进行加固可改善其刚度和强度，研究还提出了实时量测掌子面前方岩土体挤出变形的新技术——基于磁环感应的掌子面超前岩土体挤出变形量测技术，并取得成功。研究的成果可供类似工程借鉴。

Abstract: New Italian Tunneling Method (NITM) can achieve full-face excavation when tunneling through weak rocks. To study the key technology of NITM, a research project is performed in Zhejiang Province, selecting a portion of 20 m from a tunnel as test for the application of NITM. The test shows that the core technology of NITM is the solidation technology of tunnel front rock, as well as the monitoring and control of extrusion of the workface. The test study also shows that fiber glass bolt can improve the stiffness and strength of the front rock. During the research, a new method of extrusion measurement of tunnel front—a method based on magnetic induction technology has been introduced and succeeded. It is believed that the test result shall be a good reference to similar projects.