Jacking pipe joint inner wall concrete stress monitoring method based on optical fiber sensing

Abstract

The invention discloses a jacking pipe joint inner wall concrete stress monitoring method based on optical fiber sensing, and the method comprises the following steps: S1, cleaning a pipe joint ring,making an optical cable laying indication line, and brushing epoxy resin glue; S2, laying an optical cable, and pressing the compact optical cable by using a roller; S3, coating the upper part of theoptical cable with a layer of epoxy resin glue again, temporarily fixing the optical cable with a cloth-based adhesive tape, and curing the epoxy resin glue; S4, enabling the optical cable to be connected with data acquisition equipment, calculating the dependent variable of the optical fiber by measuring the frequency drift amount and the reflection wavelength drift amount of the back natural Brillouin scattering light in the optical fiber, and measuring the stress change of the concrete on the inner wall of the pipe joint. The annular glass fiber composite base optical cables are arranged onthe three sections of the pipe joint, the frequency drift amount and the reflection wavelength drift amount of back natural Brillouin scattering light in the optical fiber are measured through the data acquisition equipment, and then the dependent variable of the optical fiber is calculated and used for representing concrete stress changes.

Description

technical field

[0001] The invention relates to the field of pipe jacking stress monitoring, in particular to a method for monitoring concrete stress on the inner wall of pipe jacking joints based on optical fiber sensing. Background technique

[0002] As a trenchless technology, pipe jacking technology has the advantages of fast construction speed, high degree of automation, saving human resources, and harmonious coexistence with the environment. It has been increasingly used in the construction of underground tunnels. In order to achieve long-distance pipe jacking, the friction between the pipe and the surrounding soil or surrounding rock should be reduced and overcome as much as possible. Common measures include reducing the jacking distance between the relays, increasing the jacking force, and injecting lubricating materials, etc. However, under complex geological conditions, long-distance pipe jacking still often encounters the situation that the jacking is blocked, an...

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