分布式光纤传感技术在钻孔灌注桩检测中的应用

布里渊光时域反射计(BOTDR)是近年来国际上研发成功的一项新型的分布式光电传感技术,该技术已开始广泛地应用于结构体的温度、应变、应力检测。尝试将这一技术应用于钻孔灌注桩试桩中桩身轴力分布、侧摩阻力分布及桩端阻力等的检测;研发了一套传感光纤的埋设工艺;提出了一种基于小波分析和移动平均法的BOTDR检测数据频谱处理方法;通过一个工程实例对这一技术应用于钻孔灌注桩检测的可行性进行了论证。研究结果表明:基于BOTDR光纤传感技术的钻孔灌注桩桩基分布式检测是一个十分有效的方法,它与传统的钢筋计、土压力盒等点式检测技术相比,具有分布式、一端检测、不需回路、长距离、耐久性好、成活率高、抗干扰强和与被测物协调性能好等优点,可作为一种新型的分布式桩基检测技术加以推广。

Application of distributed fiber optic sensing techniques in bored pile detection

The Brilliouin Optical Time Domain Reflectometer(BOTDR) was a new distributed optical-electronic sensing technique successfully developed abroad.It had been widely applied in detecting temperature,strain and stress of the structures.BOTDR was employed to detect the distribution of strain,side friction and tip resistance of the bored piles.The technology embedded on the sensing optical fiber was developed,a spectral processing method of BOTDR detection data was presented based on the wavelet analysis and moving average method,and the feasibility of using BOTDR to detect the bored piles was demonstrated through a practical engineering project.It was indicated that the BOTDR-based distributed detection technique for the bored piles was quite effective.Compared with the traditional point-mode monitoring techniques such as strain gauge and earth pressure cell,there were obvious advantages for BOTDR such as distributing,single-end detection,long-distance,durability,high survival rate,strong anti-interference and better coordination,and it was a very potential technique for the pile detection.