Assessment of Landslides using Acoustic Real-time Monitoring Systems (ALARMS): Sensor Technical Development

Lead Research Organisation: British Geological Survey
Department Name: Geoscience Technologies

Abstract

Slope failures annually cause many thousands of deaths and damage built environment infrastructure world-wide. There is an urgent need for low cost instrumentation that can provide an early warning of slope instability to enable evacuation of vulnerable people and timely repair and maintenance of critical infrastructure. This project aims to design and assess field performance of a prototype acoustic slope displacement rate sensor. Sensors developed through research will be re-engineered and these new sensors will be installed at problem road and rail slopes to investigate how they perform compared to traditional more costly instrumentation.
 
Description This EPSRC grant has helped bring through the ALARMS instrumentation to the point where it can be routinely deployed at field sites following field trials of on active landslides it has proven that the technology works. It can provide an early warning of failure because it is sensitive to small displacement rates that occur prior to larger disruptive slope movements and it can provide continuous information on the rates of slope displacements. It has helped to establish an extensive field data set comparing behavior of ALARMS with both manually read and in-place inclinometers.

The ALARMS instrumentation works by measuring and analysing the acoustic emission behavior of soil and rock to establish when a landslide is imminent so that preventative action can be taken. Noise created by movement under the surface builds to a crescendo as the slope becomes unstable. Gauging the increased rate of generated acoustic emission enables warning of catastrophic slope collapse to be made. The detection system consists of one or more sensors installed across the slope that presents a risk of collapse. The sensors record the acoustic activity of the soil and rock as it deforms. Monitoring detects only high frequency sound so that background noise is not considered and hence false alarms are avoided.

The developed system monitors acoustic emission rates, created by inter-particle friction in soil and crack propagation and displacement on discontinuities in rock, are proportional to rates of movement and so increased acoustic emissions mean a slope is closer to failure. Once a certain emission rate is recorded, the system can send a warning, via a text message, to the authorities responsible for safety in the area. As well as the life-saving implications for countries prone to disastrous landslides, the technique can also be used in monitoring the condition of potentially unstable slopes built to support transport infrastructure.
Exploitation Route The developed research has highlighted the possibility of monitoring slope stability and slope failure through monitoring Acoustic Emissions which could be taken across to non Geotechnical areas to provide near real time assessment of stability within critical non-geological substrates.
Sectors Construction,Environment,Transport
URL http://www.slopealarms.com/index.php/publications/
 
Description As part of a Loughborough University collaboration with project partners INGLAS in April 2014, ALARMS provided a complementary component of the Sentinel for Alpine Railway Traffic (SART) project, jointly funded by the Austrian Railway (OeBB) and the Austrian Research Council at the research site located at Grossreifling (Styria, Austria. The site consists of a steep conglomerate slope that threatens a section of railway line. The trial site was set up with ground water flow linked to rainfall has been The system takes advantage of a dual approach: early warning of imminent rockfalls, given by acoustic emission generated within the rock slope, and detection of rock fall occurrence, provided by a light static catch fence instrumented with movement sensors that give information about the debris that detaches from the slope and impacts the fence. The AE monitoring system comprises three waveguides grouted into the rock slope, two horizontal and one vertical. A strong response to ground water flow linked to rainfall has been established. The critical time for slope stability is in the spring following snow melt. Monitoring will continue through spring 2016.
First Year Of Impact 2014
Sector Environment,Transport
Impact Types Economic
 
Description Loughborough University
Amount £20,000 (GBP)
Funding ID Enterprise Project Group 
Organisation Loughborough University 
Sector Academic/University
Country United Kingdom
Start 05/2012 
End 12/2012