SMITH, A. and DIXON, N., 2014. Quantification of landslide velocity from active waveguide generated acoustic emission. Canadian Geotechnical Journal, 52(4), pp. 413-425.
Acoustic emission (AE) has become an established approach to monitor stability of soil slopes.
However, the challenge has been to develop strategies to interpret and quantify deformation behaviour
from the measured AE. AE monitoring of soil slopes commonly utilises an active waveguide which is
installed in a borehole through the 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 and this
generates AE that can propagate along the waveguide. Presented in the paper are results from the
commissioning of dynamic shear apparatus used to subject full scale active waveguide models to
simulated slope movements. The results confirm that AE rates generated are proportional to the rate
of deformation, and the coefficient of proportionality that defines the relationship has been quantified
(e.g. 4.4 x 105 for the angular gravel examined). The authors demonstrate that slope velocities can be
quantified continuously in real-time through monitoring active waveguide generated AE during a
slope failure simulation. The results show that the technique can quantify landslide velocity to better
than an order of magnitude (i.e. consistent with standard landslide movement classification) and can
therefore be used to provide an early warning of slope instability through detecting and quantifying
accelerations of slope movement.