Mining-induced subsidence monitoring via horizontally deployed fiber optic sensing nerves: integrated laboratory and field investigations

Monitoring mining-induced ground subsidence is critical for geotechnical safety, yet conventional borehole-installed sensors in aeolian sand areas are prone to burial and damage. This study employs an integrated monitoring system combining Brillouin optical time domain reflectometry (BOTDR), global navigation satellite system (GNSS), and interferometric synthetic aperture radar (InSAR) to evaluate mining-induced subsidence. A 1-km horizontally deployed fiber optic sensing nerve (FOSN) was implemented to capture the spatiotemporal evolution of subsidence troughs. To enhance cable-soil coupling in the field, specialized T-shaped anchors were designed and deployed. The distributed strain results were combined with GNSS and InSAR measurements to provide a coordinated point-line-plane characterization of mining-induced ground subsidence and its impact on critical surface structures such as high voltage towers (HVTs). Furthermore, laboratory experiments were conducted to analyze deformation patterns under uneven subsidence using fiber optic strain data. Based on the experimentally obtained datasets, a transformation model was developed to quantitatively estimate ground subsidence from distributed strain measurements. This work highlights the effectiveness of horizontal FOSN for ground subsidence monitoring and provides practical guidance for optimizing anchor layouts in aeolian sand regions.