Tunnel convergence deformation distribution fiber monitoring method and system thereof

Abstract

A tunnel convergence deformation distribution fiber monitoring method is disclosed. A setting method of a distributed fiber convergence deformation monitoring sensor is adopted. The method is characterized in that: a sensing fiber is arranged on a matrix sheet material surface which has a same shape with an inner-side curved surface of a shield tunnel concrete segment so as to form a distributed fiber convergence deformation sensor and two ends of the sensor are respectively fixed on the inner side of the concrete segment; a cross section is in shapes of a rectangle, a U shape, a semi-circle or an arc or a circular ring; the sensing fiber has two parallel paths; one path is tight buffer fiber, which is used to measure strain alonga radial direction of the sensor; the sensing fiber is arranged on the surface of the sheet material sensor; using Brillouin optical time domain analysis (BOTDA) method, through calibrating correlation between a sensor gauge length convergence value and sensing fiber strain variation, convergence state change information of the tunnel section can be converted and measurement of the tunnel section convergence value can be performed. By using the invention,monitoring and measuring precision of the convergence state of the any representative section of the tunnel is high.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering monitoring, and relates to a method and system for detecting convergence deformation of a shield tunnel section based on distributed optical fiber sensing technology. Background technique [0002] The tunnel lining structure will be deformed during construction and operation. To ensure the safety of the tunnel, it is particularly important to monitor the convergence deformation of its section. At present, distributed optical fiber sensing technology has two optical fiber arrangement methods in the tunnel convergence measurement system, the first is full-contact type, and the second is fixed-point contact type. Using the first method, the optical fiber should be pasted on the inner wall of the tunnel segment with adhesive materials such as epoxy resin, and the obtained change law of the strain of the optical fiber along the tunnel section should be reversed to show that the converg...

AI Technical Summary

Problems solved by technology

However, after the cable is tensioned and fixed for a long time, relaxation and creep often occur, and this part of the deformation is often difficult to consider quantitatively, so it will affect the actual measurement results and cause misjudgment

Therefore, the above two application methods of distributed optical fiber sensing technology have certain disadvantages, and new methods and means need to be studied in the aspect of tunnel convergence deformation monitoring

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