A distributed fibre optic monitoring method for ground subsidence induced by water pipeline leakage

After a water supply pipeline experiences leakage due to damage, the surrounding soil is prone to erosion, leading to the formation of underground voids. As the voids gradually expand, there is a high possibility of triggering ground subsidence accidents. Monitoring ground deformation is the simplest and most effective method for capturing the process of ground subsidence development. Among various methods of ground deformation monitoring, distributed optical fibre sensing has advantages such as real-time performance, distributed measurement, and ease of networking. This paper investigates the monitoring effectiveness of distributed optical fibre strain sensing technology on ground subsidence induced by underground voids under different conditions through indoor model experiments. To convert the measured strain of the optical fibre into ground subsidence, this paper proposes a strain-displacement conversion method based on the sequence-to sequence (Seq2Seq) model. The method is validated using data from indoor model experiments. The research results indicate that distributed optical fibre sensing technology can effectively monitor the strain distribution of soil during the subsidence process. It can identify the development location of ground subsidence and reveal the deformation evolution patterns. The strain-displacement intelligent conversion model based on Seq2Seq can convert the strain monitored by the optical fibre during the ground subsidence process into ground subsidence. Compared to traditional methods, this conversion model exhibits higher accuracy.