Method for detecting tubular pile driven in soil layer by FBG-BOTDA (Fiber Bragg Gratting-Brillouin Optical TimeDomain Analysis) joint sensors

Abstract

The invention discloses a method for detecting a tubular pile driven in a soil layer by FBG-BOTDA (Fiber Bragg Gratting-Brillouin Optical TimeDomain Analysis) joint sensors. The method specifically comprises the following steps: arranging a plurality of F-B joint sensors on the surface of the tubular pile along the length direction, wherein the F-B joint sensors comprise FBG sensors and BOTDA sensors, the FBG sensors detect a strain change rule of a monitoring point in a driving process and a pipe connecting process so as to obtain dynamic and static data of the monitoring point, and the BOTDA sensors monitor the strain change characteristic of a pile body under the static state of the tubular pile so as to completely hold the strain development trend of the pile body. The FBG-BOTDA joint monitoring disclosed by the invention is capable of accurately acquiring the dynamic and static data of the monitoring point and completely holding the strain development trend of the pile body, thereby making up the defect of dynamic monitoring of a full-distributed sensing technology and making up the misjudgment of overgeneralization of a point sensor. Especially, with the mature of a demodulation technology, the FBG sensors and the BOTDA sensors are reused, and an FBG-BOTDA joint monitoring technology is wide in utilizing prospect.

Description

technical field [0001] The invention relates to a FBG-BOTDA combined sensor detection method for pipe piles driven into soil layers. Background technique [0002] As a foundation treatment method and pile foundation form, pipe piles have the advantages of short construction period, convenient construction, industrialized production, no pollution to the construction site, considerable economic benefits, and strong adaptability. However, during the construction of pipe piles, there are often problems such as broken pile head, bursting of pile body, and difficulty in penetration of pile body, which seriously affects the promotion and use of pipe piles. For example, the foundation of the first phase of Tianji Power Plant uses Φ600×110AB PHC pipe piles. In the process of driving chimney foundation piles in the early stage, 58 piles were driven in first, and when 13 piles were driven into the soil to a depth of about 20-24m, The pile body was damaged 4-6m away from the pile tip [...

AI Technical Summary

Problems solved by technology

The large strain method has relatively high requirements on the monitoring environment, sensor installation, pile top condition, hammer height, hammer weight, etc. It is difficult to meet the on-site conditions, and the measurement curve and the actual situation have large errors. Some regional quality supervision stations have not recognized it. The test

Due to its shortcomings such as poor long-term stability, low survival rate, complicated construction, and point type, the resistance strain gauge cannot well meet the monitoring needs of the driving process of pipe piles.

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