Alister Smith and Neil Dixon, School of Civil and Building Engineering, Loughborough University, Leicestershire, UK, Philip Meldrum and Edward Haslam, British Geological Survey, Keyworth, Nottinghamshire, UK. This paper was first published in GE’s October 2014 edition.
The paper details the concept of retrofitting inclinometer casings with active waveguides in order to provide subsurface instrumentation that can monitor the stability of slopes continuously and in real-time. The operation of the active waveguide, the unitary battery operated Slope ALARMS acoustic emission sensor and warning communication system are described. A field trial previously reported by the authors demonstrates that acoustic emission rates generated by active waveguides are proportional to the velocity of slope displacements, and can therefore be used to detect changes in rates of movement (that is accelerations and decelerations) in response to destabilising (for example rainfall) and stabilising (for example remediation) effects.
The paper presents the results of a field trial of the acoustic monitoring system retrofitted inside an inclinometer casing in a reactivated landslide at Hollin Hill, North Yorkshire, UK. The study demonstrates that this approach can provide continuous information on slope movements with high temporal resolution. Converting manually and periodically read inclinometer casings into continuously monitored active waveguides using Slope ALARMS sensors is a cost effective solution to providing real-time information that could be used in the protection of people and infrastructure.