掌子面超前岩体挤出变形量测新技术及其应用
A New Technology and Its Application in the Measurement of Tunnel Front Rock’s Extrusion

掌子面超前岩体挤出变形是判断隧道掌子面是否稳定的重要指标，因此，掌子面超前岩土体挤出变形的量测技术的研发十分重要。目前国内外所用的传统的多点位移计技术和专用的滑动伸长计技术都存在缺点：前者监测寿命短，成本高；后者价格昂贵，维护困难。本文介绍了一种基于磁感应原理的掌子面超前核心岩体挤出变形的量测新技术。这种新技术采用磁环作为埋设元件，磁感应仪作为感测仪表，可以随掌子面推进连续进行前方核心岩体的挤出变形量测，其优点是：成本低，效果好。文章最后介绍了它在浙江省奇坑隧道新意法试验段的应用情况，应用结果表明其性能和效果很好，值得推广使用。
Front rock’s extrusion is an important index for determining whether the workface is stable or not. Therefore, the research and development of measuring technology for extrusion become increasingly important. From home to abroad, present used measuring technologies, which can be classified as traditional multi-point extensometer and sliding extensometer, all have their shortcomings: the former has short service life span and is expensive while the latter is both expensive and fragile. This paper introduces a new technology based on magnetism, in which the magnetic rings are measuring cells and the graduated rod is the measuring tool. This technology makes the measured cells long-lived and can remain until the workface being excavated. Its significant advantage is cost-effective and quality-reliable. In the end, this paper has displayed an application of this new technology in the tunneling of NITM trial section of Qikeng tunnel, which is located in Zhejiang Province, and the application has showed that this new technology has reaped good effect and is recommendable for other projects.