灌注桩检测中BOTDR温度补偿试验研究

Experimental Study on BOTDR Temperature Compensation in Bored Pile Detection

运用基于布里渊光时域反射计(简称BOTDR)的温度自补偿方法,采用特殊封装的温度传感光纤,检测了灌注桩在混凝土养护期内由温度变化引起的应变变化量和静载荷试验过程中的温度变化。结果表明:混凝土养护末期由温度引起的应变变化量很小,说明在混凝土养护末期,其水化热已消散;在灌注桩静载荷试验过程中,由温度补偿光纤所测的温度变化引起的应变量值也很小。因此,在灌注桩光纤分布式检测中,由温度引起的光纤应变检测误差可忽略不计。

Based on the temperature compensation method of Brillouin Optical Time-Domain Reflectometer （BOTDR）, specially packaged fibers of temperature sensing were used to detect temperature variations in static load test and strain changes caused by the change of temperature during concrete curing period of bored pile. The research results show that the strain changes due to temperature are small at the end of curing period, indicating that hydration heat has been dissipated; and the same conclusion holds as well in the static load test process. As a result, the strain detection error caused by temperature can be ignored in the distributed fiber optic sensing detection of bored pile.