Tunnel Health Monitoring Using Seismics

Abstract

In this thesis a new approach, called THEAMTM, is presented. The THEAMTM methodology is a non-invasive tunnel health monitoring method using active seismic. The method incorporates geophysical seismic analysis methods and geotechnical engineering with available wireless technologies. The fundamental idea of the THEAMTM procedure is to artificially generate a controlled seismic signal at the tunnel wall, and to record the response from the tunnel surrounding system at fixed receivers attached to the tunnel surface. The change in seismic signatures overtime are used as a precursor about the tunnel rock wall conditions, such as, new emerging cracks or any structural changes.

The THEAMTM procedure was applied at Oslofjord tunnel. The results of this study suggest that the THEAMTM methodology is a robust and potentially very applicable procedure for long-term monitoring of the tunnel rock wall conditions before any hazardous collapse. This method is more powerful compared to conventional method like visual inspection, because it provides fast and continuous reliable information about the geological rock wall conditions in the tunnel. Furthermore, the THEAMTM method is easy to accomplish because once system is instrumented the data is acquired by remote control from office.