A method and system for rapid detection of grouting voids after tunnel lining

Abstract

This invention discloses a rapid detection method and system for grouting voids after tunnel lining. It belongs to the field of non-destructive testing technology in civil engineering. The method includes: deploying a DAS fiber optic sensor array along the tunnel lining; exciting artificial seismic sources at fixed intervals and receiving signals at fixed offset distances; generating equidistant profiles; calculating the theoretical travel time of reflected waves from the grouting layer interface; extracting the interface reflection amplitude from the profile to generate a CBL curve, and simultaneously extracting the reflected wave travel time to generate a grouting travel time curve; and rapidly identifying areas of cementation anomalies and locating grouting voids by analyzing the amplitude anomalies and travel time deviations of the two curves. The system includes corresponding functional modules. This invention uses distributed fiber optic sensing to achieve continuous coverage across the entire tunnel section, combined with a hyperbolic joint interpretation mechanism, offering advantages such as high detection efficiency, strong anti-interference capabilities, and intuitive on-site interpretation. It solves the problems of low efficiency and reliance on complex inversion methods in traditional approaches.

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