Performance evaluation of distributed strain sensing nerves for monitoring ground collapse: A laboratory study

Abstract

Ground collapse events frequently lead to significant economic losses, catastrophic injuries and fatalities. There is a growing need for sensitive monitoring technologies to locate and predict potential ground collapses. This study aims to evaluate the performance of fiber optic (FO) cables for ground collapse monitoring. A model test was conducted in laboratory, and the optical frequency domain reflectometry (OFDR) and particle image velocimetry (PIV) techniques were combined to monitor the whole collapse process. The strain profiles measured by FO cables under different soil failure mechanisms were analyzed in detail. In the case of shallow sinkholes, the soil failure surfaces emanate from the edges of sinkholes and eventually propagate to the ground surface, and the shape of failure surfaces gradually changes from curvy to vertical. Micro-anchors significantly enhance the interface bonding between cables and surrounding soil. Moreover, the settlements calculated based on strain measurements match well with actual settlements.