Experimental Study On Distributed Optical Fiber Sensing Technology For Monitoring Of Engineering Deformation

Pavement diseases are usually caused by the ground settlement. Mastering theland subsidence trends accurately is very important for the road construction.Similarly, mastering the foundation pit deformation in time is the essential assurancefor successful construction of the project. As a direct reaction to the foundation pitdeformation, the horizontal displacement monitoring is very important.Due to the improved demand for structural health monitoring of subsidencemonitoring and horizontal displacement monitoring methods, this dissertation usingthe system fiber-optic strain basing on BOTDA Brillouin distributedstrain-temperature measurement system and combining with two simplifiedsimulation test models, to simulate and verify the application of distributed opticalfiber on the subsidence monitoring and horizontal displacement monitoring, whichincludes the research of the perceptual characteristics of Brillouin scatteringdistributed optic fiber and temperature compensation method. The main works andconclusions are as follows.1. The principle of optical Brillouin sensing technology has been introduced. Itsstrain-temperature coupling effect has been discussed in details and a noveltemperature compensation for strain measurement is put forward.2. Based on the BOTDA distributed optical fiber strain-temperaturemeasurement monitoring system, the flexure deformation of H-Beam combined withsettlement calculation model, the test of the simulation steel pile body settlementdeformation monitoring was carried out. The test results show this combination ofsimulation experiments and computational model is not feasible. The applicability ofthe method for long-distance linear settlement deformation monitoring can bevalidated further.3. Based on the BOTDA distributed optical fiber strain-temperaturemeasurement monitoring system, the flexure deformation of H-Beam combined withhorizontal displacement calculation model, the test of the simulation steel pile bodyhorizontal displacement deformation monitoring was carried out. The test resultsshow that the simulation test and the combination of the calculation model arereliable. This method realized the temperature self compensation, fundamentallysolved the problem of the environment temperature on the interference of the monitoring results in the practical engineering, And it can be used in the practicalengineering structure beam, column, oil pipelines and the pile deformationmonitoring.