隧道拱顶下沉监测

为了保障隧道的安全施工,及时掌握隧道整体的稳定情况,需要进行隧道拱顶下沉监测.在介绍隧道内监测基准点、工作基点和监测点的建立方法的基础上,说明了精密水准测量方法和三角高程测量方法,重点讨论了隧道变形自动监测系统的应用.研究表明,精密水准测量方法和静力水准仪法精度可靠,但对于大断面隧道,操作相对不便;三角高程测量法可迅速测出相对拱顶下沉值和绝对拱顶下沉值,前者可以自由设站,后者可在控制点上设站,操作灵活方便,但不能实时连续观测;隧道变形自动监测系统无论巴赛特系统、全站仪动态监测系统或者断面仪动态监测系统,均可实现全天24小时无人值守、连续监测隧道拱顶下沉变形,但如果布置许多断面,硬件成本甚高.实践中,应相机抉择综合采用各种方法.

Crown Settlement Monitoring of Tunnels

To ensure the safety of tunnel construction, the establishment of standard benchmarks ,stations and monitoring targets is introduced, the principle of the traditional crown settlement monitoring method with levels and total stations is explained, mainly the application of automatic tunnel deformation monitoring systems is discussed. It is shown that the levels provide extremely repeatable and reliable measurements , but the operation is relatively inconvenient for large tunnel sections; the total stations are flexible and easy to operate, but neither real time nor dynamic observation can be realized; the automatic tunnel deformation monitoring systems including Bassett Convergence System .Total Station Monitoring System and Profiler Monitoring System can continuously monitor the deformation automatically, however the hardware would cost a lot when many sections are laid out. So they should be integrated reasonably in practice.