关键词: 塔柱;外观检测;熵值法;综合评价;三峡升船机;

Abstract: Now available layout of optical fiber sensors has defects of single deployment, which could not meet demands of various projects. For this reason, according to the requirements of horizontal displacement monitoring of practical engineering pile, we develop a new single-U shaped and a multi-U shaped layout. Meanwhile, a simple supported beam of PVC pipe is designed, and its bending deformation and strain were measured by using distributed optical fiber sensor. The deflection of the pipe is calculated by different combination of strain, and the errors of each combination are analyzed. Finally, the above two optical fiber layout methods were applied to the actual engineering pile horizontal displacement monitoring, and the effect of optical fiber sensor monitoring data were compared. The experimental and practical engineering analysis show that when the distributed fiber is used to calculate the pile displacement, the double-axis strain being perpendicular to excavation face should be firstly used to calculate the pile displacement, and then the other axial strains can be converted into the lateral strain of the foundation pit, and further the double-axis strain can be used to calculate the pile displacement, while the multi-axis strain calculation will cause redundant errors. In practical engineering application, the monitoring effect of distributed optical fiber sensor is better than that of inclined pipe.

Key words: foundation pit monitoring; envelope structure; optical fiber sensor; layout method of optical fiber; displacement calculation