引大济湟长距离引水隧洞安全监测设计研究

Study on Safety Monitoring Design of Long-Distance Diversion Tunnel of Datong-to-Huangshui Water Diversion Project

根据引大济湟工程引水隧洞的工程特点,在充分考虑安全监测技术发展现状,并方便监测自动化系统组建的前提下,永久监测仪器选用了新型光纤光栅传感器,以适应信号长距离传输需要。在隧洞内钻孔埋设仪器对主体土建施工影响很大,因此将施工期监测和永久监测分开考虑,施工期监测根据开挖揭露的地质缺陷随机布置,以表面安装设施为主,尽量不影响主体土建施工;永久监测根据结构设计及地质条件按断面法布置,以钻孔埋设仪器为主,待隧洞贯通后再集中进行埋设,尽量不占用土建直线工期。监测自动化系统在通水前一次性建成,主要采集设备全部设在隧洞外,以确保系统能长期可靠运行。

According to the engineering characteristics of the water diversion tunnel of Datong-to-Huangshui Water Diversion Project and taking full account of the development status of safety monitoring technology and facilitating the establishment of automatic monitoring system, a new type of fiber Bragg grating sensor was selected as permanent monitoring instrumentation to meet the needs of long-distance signal transmission. Drilling and installing instrumentation in the tunnel had great impacts on the main civil construction. Therefore, the monitoring during the construction and permanent operation periods were treated separately. The monitoring during the construction period was randomly arranged according to the geological defects exposed by the excavations and the surface monitoring facilities were mainly used to minimize the impacts on the main construction. Permanent monitoring was arranged mainly by boring and installing instrumentation the cross-sections according to the structural design and geological conditions. After the tunnel transfixion, the permanent instruments would be installed in a short time, so as not to occupy the civil construction period. The automatic monitoring system would be built at one time before that the water flows through the tunnel and the main acquisition equipment would be all set up outside the tunnel to ensure that the system could run reliably for a long time.