基于BOTDR的锚杆拉拔试验研究

对锚杆应力分布状态的监测一直是岩土锚固工程中的难题之一。针对基于布里渊光时域反射计分布式光纤传感技术的特点设计了传感光纤的布设方案及安装工艺;结合锚杆拉拔试验,分析了这一技术用于锚杆应力状态监测的可行性。结果表明:基于BOTDR的分布式光纤传感技术具有结构简单、易于布设安装和测量范围大的优点,可以直观地得到锚杆在各级荷载下锚杆的通体应力、应变分布特征,试验中获得的多项测试数据的规律性都较好,该技术在锚杆应力应变分布状态的长期监测中具有广阔的应用前景。

BOTDR-based pull-out tests on anchor bolts

Monitoring of the stress distribution along anchor bolts is a critical issue for ground anchorage engineering.Considering the characteristics of distributed fiber optic sensing technology—Brillouin optical time-domain reflectometer(BOTDR),the layout and installation of the sensing fiber on anchor bolts were designed.Combining the pull-out tests on anchor bolts,the feasibility of this method was discussed.The test results demonstrated that BOTDR-based distributed fiber optic sensing technology had some unique advantages,such as easy installation and large measurement range.It could veritably detect the axial strain and stress distribution of the anchor bolts under different levels of load.Thus the conclusion could be drawn that BOTDR-based distributed monitoring technology had wide application prospect in geotechnical engineering.