光纤传感技术在地下工程中的应用

研究目的光纤传感技术是一种新型的监测技术。新建北京地铁5号线崇文门站需要从既有运营地铁下穿过,为控制开挖引起的土层沉降,需要对施工中采用的超前大管棚的应变进行测试,传统的测试手段难以满足要求,因此采用了光纤传感技术。研究方法在大管棚施工前在其上预埋光纤传感器,并对光纤传感器进行相应的保护措施,以保证其工作正常,管棚施作时附带光纤传感器一起顶入土层中,因为光纤传感器是附着在管棚上的,应变可以通过光纤传感器反映出来。研究结论通过测试,可以看出光纤传感技术能够测试管棚应变,精度较高;光纤传感器能够在复杂的环境下测试管棚的应变,比电阻片测试更具有耐久性和适应性,光纤传感技术可以在地下工程中推广应用。

APPLICATION OF OPTICAL FIBER SENSING TECHNOLOGY IN THE UNDERGROUND PROJECT

Research purposes:Optical fiber sensing technology is a new technology of monitor supervise. The newly built Chongwenmen station of Beijing Subway Line 5 goes under the already running line. In order to control the displacement of soil layer, it is needed to test the strain of the pre-braced major diameter pipe umbrella in the construction. The traditional test methods can not satisfy with the requests.Therefore, optical fiber sensing technology is adopted. Research methods: The optical fiber sensor should be buried before the construction of the pre-braced major diameter pipe umbrella, and some corresponding protective measures should be taken to guarantees that the optical fiber sensor can work well. The pre-braced major diameter pipe umbrella goes against into in the soil layer with optical fiber sensor together, and the strain can be reflected through the optical fiber sensor because it is attached in the pre-braced major diameter pipe umbrella. Research conclusions: It is proved that the strain of pipe umbrella can be examined with optical fiber sensor with high precision in the test, and it is more durable and compatible compared to the resistance gages under complex environment. Therefore, the optical fiber sensor technology could be applied in the underground project.