InSAR Monitoring for Tunnel Stability

Geofem
Sep 30, 2025
2 min read

Monitoring ground movement above tunnelling operations is crucial for ensuring the safety and stability of surrounding infrastructure. As tunnels are excavated beneath the Earth's surface, they can induce ground settlement or displacement, potentially leading to structural damage, land subsidence, or even surface collapses.

Why Visual Inspections and In-Situ Monitoring Alone Fall Short

Visual inspections and in-situ monitoring may not be sufficient for monitoring ground movement above tunnelling operations for several reasons. Firstly, ground movement can often occur gradually and may not be readily visible to the naked eye, especially in the early stages of deformation. Subtle changes in Surface displacement may go unnoticed until they reach a critical point. The main challenges lie in the identification of the affected areas, the severity of movement, and whether this activity predates or was induced by the construction.

Tunnelling in South Asia: A Unique Challenging

Tunnelling operations in South Asia present unique challenges due to the region's rugged terrain, seismic activity, and the presence of soft, unstable soils in some areas. In such a dynamic environment, monitoring ground movement becomes particularly crucial. As tunnelling operations in this area of South Asia were underway, stakeholders needed a way to monitor the stability of the surrounding ground with a higher level of accuracy than visual inspections allow. Using InSAR technology, Geofem monitored ground deformations along tunnelling alignments with millimetric accuracy. From these insights, stakeholders could detect areas of displacement requiring further remedial attention before critical failures occurred. Areas showing settlement not due to construction of the tunnel were also identified.

Addressing Ground Movement in London's Urban Environment

This project in London faced similar challenges. In a densely populated urban environment with extensive infrastructure networks, historical buildings, and variable geology. Many of London's structures are historic and heritage buildings, which may be more vulnerable to ground movement than modern constructions. Monitoring ground behaviour, therefore, is essential to the preservation of cultural assets, minimising service disruptions and costly repairs. The affected areas can be identified, and the magnitude of the settlements measured using InSAR analysis. Project managers could assess areas of accelerated displacement requiring further attention without needing to disrupt vehicular and pedestrian traffic in a busy city centre.

The Benefits of InSAR for Tunnelling Projects

InSAR technology is transforming how tunnelling projects monitor ground stability, particularly in challenging environments like South Asia and densely populated urban areas like London. With its ability to provide accurate, real-time data, InSAR enhances safety, protects infrastructure, and minimises disruptions. Whether dealing with seismic activity, unstable soils, or historical buildings, InSAR offers a reliable solution for ensuring the long-term stability of tunnelling projects.For more information on how InSAR can benefit your infrastructure projects, contact Geofem today.