Description:
Developed at Loughborough University – in collaboration with the British Geological Survey – Slope ALARMS is a novel landslide detection system. Its patented, award-winning technology measures acoustic emissions caused by soil movement – offering life-saving, real-time monitoring of unstable hillsides.
The Challenge
Landslides world-wide cause thousands of deaths and extensive damage to infrastructure. Current systems are technologically limited and expensive – Slope ALARMS offers a revolutionary alternative.
The Concept
Slope ALARMS is a real-time AE slope displacement rate sensor. It is comprised of the following elements: transducer, pre-amplifier, filters, an integrated signal processing, data storage and communication device, power supply and a secure, acoustically insulated chamber. The integrated signal processing, data storage and communication device performs the following functions: measurement and quantification of detected AE as Ring Down Count (RDC) rates; conversion of RDC rates into displacement rates; comparison of these with trigger values and generation of alert communication. The sensor is located on an active waveguide. Deformation of the slope results in straining of the active wave guide system (i.e. deforms the granular backfill surround) leading to generation of AE. In real-time, acoustic emission RDC rates generated by the active waveguide are recorded at pre-defined time intervals and using a relationship between acoustic RDC rates and displacement rates, derived through a laboratory calibration process, quantitative information on slope displacement rates can be obtained. RDC rates are recorded and are compared to pre-determined trigger/action values based on both magnitude and changes in rate. If the trigger values are exceeded, an alert message that includes measured AE rates is sent using a wireless communication system to a nominated person(s) to enable relevant action to be taken.
The Slope ALARMS sensor is highly sensitive and can detect displacement rates as low as 0.01 mm per minute. It is designed to detect changes in soil slope displacement rate for orders of magnitude (for example, 0.01, 0.01, 0.1 and 1 mm per minute), which is consistent with established slope displacement rate classification and monitoring procedures, and it can detect changes in soil slope displacement rate within a few minutes of the change occurring. The sensor design can be configured for any length of the waveguide (i.e. including backfill type, sensor specification and cover system). Measurements can be made at continuing large magnitude displacements (>>100mm), as the interaction between granular backfill and waveguide will continue to generate AE proportional to displacement rates at the shear surface. The sensor can be re-used on other waveguides of the same design without the need for re-calibration or modification as the design is independent of the soil materials that form the slope being monitored and the slope geometry (i.e. slope height, length and slope angle). Monitoring is of subsurface slope deformations for the depth of the waveguide using one Slope ALARMS sensor located at the surface. Alerts obtained from continuous measurements are real-time therefore providing the possibility of a timely response to reduce consequences of slope failures and hence reduced risk.
The Slope ALARMS system has been re-engineered in 2012 by the British Geological Survey to produce improved performance. This includes a lower power requirement that means sensors can operate in remote locations for periods in excess of 12 months without the need to replace batteries or provide battery charging facilities. These new sensors are being used in extensive field trials.
Technology Uses
• Natural Slopes
• Coastal Slopes
• Infrastructure Cutting Slopes
• Rock Slopes
• Transport Infrastructure Landslides
Benefits
Landslides cause significant disruption to transport infrastructure and property around the world, and several technologies exist to provide monitoring and warning. However, the cost of these sensors limits the number of sites that can be effectively instrumented.
In the developing world, many thousands of people are killed by landslides. Increasing population, urbanisation, rapid changes in land use and the changing climate are placing communities increasingly in danger from landslides. The majority of these communities are in low and middle income countries located in Central and South America, Africa, the Indian sub-continent and South East Asia, where development is rapid and extremes of climate (e.g. rainfall) are common.
Slope ALARMS is a low-cost sensor that can warn of impending landslides and be deployed extensively to protect vulnerable infrastructure and communities.
Slope ALARMS detects the early signs of a landslide and raises the alarm so that timely action can be taken to avoid disaster and loss of life.
Commercialisation
Granted UK Patent
Significant on site testing around the world for over 4 years
Seeking licensees and end users around the world
Field trials are underway across the globe. If you would like to collaborate with us or find out more about Slope ALARMS, please visit our website.