海岛环境条件下超长灌注桩温度光纤监测研究∗

Study on the Temperature of Super Long Cast-in-place Pile on the Island Using Optical Fiber Sensing Technology

摘要:

为了弥补传统监测手段的不足，更好地掌握海岛环境条件下超长灌注桩温度分布规律，采用了布里渊光时域反射（BOTDR）技术，在海岛环境条件下将光纤温度传感器安装在灌注桩上，对气温变化下 116 m 长的灌注桩进行了长期温度监测试验。监测结果表明：本次用于超长灌注桩桩体温度测量的光纤传感器均存活，说明传感器布设工艺的合理性，同时从测试结果来看，光纤温度传感器基本上没有受到外力的干扰；采用 DB5 小波对光纤测试数据进行降噪；从桩体温度变化曲线来看，海岛环境条件下的超长灌注桩桩体温度变化非常复杂，桩头位置温度变化量最大，随着深度增加，温度变化量逐渐减小，至 18 m 深度处温度基本不发生变化；桩体温度场的变化存在时间效应。

Abstract:

In order to make up for the shortcomings of traditional monitoring methods and understand the temperature distribution of super long cast-in-place piles on the island， the Brillouin optical time domain reflectometer technology （BOTDR） is used， the optical fiber temperature sensor is fixed on the cast-in-place pile， and the temperature of the 116m long cast-in-place pile under the air temperature fluctuation is measured by long-term monitoring in this paper. The monitoring results show that： the optical fiber sensors used for the temperature monitoring of the super long cast-in-place pile all survived， indicating the rationality of the sensor layout method. It can be inferred from the monitoring results that the optical fiber temperature sensor is not disturbed by external forces； the DB5 wavelet is used to reduce the noise of the optical fiber data. From the pile temperature curve， the temperature change of the super long cast-in-place pile on the island is very complex， the temperature change at the pile head is the largest， and it decreases gradually with the depth. At a depth of 18 m， the temperature does not change， the pile temperature has a time effect.