分布式传感光纤测量疏浚土大型充填袋变形

港工建设中采用航道疏浚土作为新型筑堤材料的关键技术研究,对于解决资源短缺和环境制约等问题具有重要意义。由于无法应用传统点式监测技术测量充填袋充填、加载中袋体的受力及变形过程,针对高含泥量疏浚土大型充填袋袋体受力及变形监测等工程实践问题,通过室内标定试验和现场原型试验,开展了传感光纤选型、胶结固定及保护方式、测量精度及误差分析、工程原型应用测试等分布式光纤传感技术应用于高含泥量疏浚土大型充填袋受力及变形测量的可行性研究。试验研究表明,疏浚土大型充填袋袋体受力及变形监测中应选用柔性护套应变传感光纤,以柔性胶固定;选择合适的传感光纤能够使袋体受力及变形的测量精度达到±30με,监测空间分辨率0.1 m,最大应变测量范围30 000με;分布式光纤传感技术是疏浚土大型充填袋袋体受力及变形监测的可靠新型测量方法。

Experimental studies of distributed optic fiber sensor for measuring deformation of large filling bag with dredged soil

It is very significant to study the key technology in taking the dredged soil as new construction material in the port engineering considering the resources shortage and environmental restriction. The traditional point-supporting measurement technology could not be utilized to measure the deformation of a large filling bag in its filling and loading process. The engineering practical problems such as measuring the deformation of large filling bag with dredged high clay content soil have received much concern at the present stage. Based on the laboratory calibration tests and filed prototype tests， the selection of the optic fiber sensor， cemented fixation and protection， measurement accuracy and error analysis， and application testing studies in the filed works have been carried out. The application feasibility of the distributed optic fiber sensor to measure the deformation of the large filling bag with dredged soil is discussed. The research results show that the optic fiber sensor with flexible sheath should be adopted for measuring the deformation of the large filling bag with dredged soil. And the measurement accuracy would be up to ±30 με with the apposite optic fiber sensor, the monitoring spatial resolution could be 0.1 m, and the maximum strain measurement range could be within 30 000 με. The distributed optic fiber sensor could be adopted as a new reliable method to monitor the deformation of the large filling bag with dredged soil.