Abstract
Acoustic emission (AE) has become an established approach to monitor the stability of soil slopes. However, the challenge has been to develop strategies to interpret and quantify deformation behaviour from the measured AE. This paper presents the first comparison of continuous AE (measured using an active waveguide) and continuous subsurface deformation measurements. The active waveguide is installed in a borehole through a slope and comprises a metal waveguide rod or tube with a granular backfill surround. When the host slope deforms, the column of granular backfill also deforms, generating AE that can propagate along the waveguide. This paper presents results from a field trial at a reactivated soil slope in North Yorkshire, UK. The measurements confirm that AE rates generated are directly proportional to the velocity of slope movement (e.g. the AE rate versus velocity relationship determined for a series of slope movement events produced an R2 value of 0·8) and demonstrate the performance of AE monitoring of active waveguides to provide continuous information on slope displacements and displacement rates with high temporal resolution.
Highlights
AND BACKGROUND In soil, acoustic emission (AE) is generated by inter-particle friction and the detection of AE is an indication of deformation
The results prove that AE rates generated are directly proportional to the velocity of slope movement
N the acoustic emission (AE) rate response to first-time rupture failure, where the velocity of slope movement varies over several orders of magnitude
Summary
AND BACKGROUND In soil, acoustic emission (AE) is generated by inter-particle friction and the detection of AE is an indication of deformation. In order to monitor AE generated by deforming slopes formed of finegrained soils, Dixon et al (2003) devised the active waveguide. The active waveguide (shown in Fig. 1) is installed in a borehole that penetrates any shear surface or potential shear surface beneath the slope; it comprises a steel waveguide (to transport the AE signals generated at the shear surface to the ground surface with relatively low attenuation) and angular gravel backfill (to generate relatively high energy AE as the slope deforms, which can propagate along the waveguide). AE monitoring using active waveguides is most applicable to soil slopes that fail along a defined shear surface as the development of such a surface, or reactivation of an existing surface, will shear the waveguide granular backfill and generate high levels of detectable AE. An increasing rate of deformation (i.e. in response to increasing slope velocity) within the active waveguide
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
