Research On Pile Integrity Detection Method Based On Distributed Optical Fiber

Pile foundation is the most widely used type of deep foundations. The number ofpiles is growing rapidly in China every year. The bad quality of piles seriouslyendangers the safety of structure and causes huge economic losses. Therefore, piletesting plays a very important role. This paper briefly describes the common method ofpile integrity testing, and then proposes a pile integrity detection method based ondistributed optical fiber.Two formation ways of strain field are describes in Chapter3: by using the modalanalysis method to identify structural strain modal and by using the concrete shrinkagecharacteristics to form the strain field. The strain detection technology based onBOTDR distributed optical fiber can achieve distributed measurement of all points inthe structure，so that the distribution of strain field could be obtained.The defect indicator approach based on the strain field is discussed inChapter4,aswell as the calculation method of the defect position indicators and defect levelsindicators in truss and entity structure, to determine the position and integrity of thedefect.A simply supported beam and a pile model in different conditions are establishedwith ANSYS in Chapters5and Chapters6. The distribution of strain field is obtainedby modal analysis and static analysis. Defect indicators are calculated by using theindicators method. The calculated results are compared with the actual defect to verifythe feasibility of the indicators method.