提出了一种基于布里渊散射光时域反射监测技术(BOTDR)的基坑锚杆(索)分布式检测方法,包括:适用于锚杆(索)检测的金属基索状应变感测光缆和紧包护套感测光缆,感测光缆铺设方法,数据采集,锚杆(索)轴力与侧摩阻力计算,锚固性能评价。最后以南京某基坑为例,利用该方法对3种不同锚杆(索)进行了现场拉拔测试。结果表明该方法可以获得沿锚杆(索)各点的应变值,实现全分布式测量,方法可行,结果准确。
In this paper,we propose a Brillouin optical time domain reflector( BOTDR)-based method for testing the foundation anchor. This method is composed of the followinge steps. First,we choose appropriate strain sensing cables suitable for anchor detection. Then,we introduce a laying method of the sensing cable and a data collection method. Finally,we calculate the tensile stress and lateral friction,and evaluate the performance of the anchors. Taking a foundation pit in Nanjing as an example,we use this method to measure the strain distribution along the anchors during field pullout tests. The results show that we can obtain the strains along the whole anchor length,hence realizing truly the distributed test of anchors,and the method is feasible while the results are accurate. The method may provide a new technique for testing the foundation anchors.