Experimental Study of the Premonitory Factors for Internal Erosion and Piping Failure of Landslide Dams
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Abstract
Description
ydrodynamics is prerequisite for a better understanding of the complex mechanisms of
internal erosion and piping failure of landslide dams. To this end, a series of large-scale
(outdoor) physical experiments were conducted to evaluate the premonitory factors and the
critical conditions for piping failure of landslide dams. The experimental facility comprises
a horseshoe-shaped trapezoidal barrier of length 8 m and height 2 m, with an open end for
the construction of the dam models. Internal deformations associated with the onset of
internal erosion were monitored with four strain gauges inserted into a PVC pipe and
laid *0.5 m above a 0.2 m-wide artificial drainage channel comprised of uniformly-sized
pebbles and gravel. The rate of internal erosion and piping was measured with a turbidity
sensor installed near the potential exit point of the seepage water to record the changes in
turbidity of the fluidized sediments. Transient variations in the upstream reservoir were
monitored with a 50 kPa capacity pore-pressure transducer while the hydrodynamic
changes that occurred during the onset of internal erosion and piping were monitored with
three pore-pressure transducers. The deformation behaviour of the dam models was
monitored with two multi-function analog laser displacement sensors while self-potential
measurements were made to track the development of the piping hole under steady-state
flow conditions. The experimental results indicated that the emergence of an effluent
seepage of high turbidity at the downstream face of the dam models coincided with high
negative self-potential anomalies. This was also found to correlate with the development of
high pore-water pressures (4–8 kPa) which subsequently led to a gradual decrease in the
dam height (settlement). These large-scale (outdoor) physical experiments provide
important information which may be useful in estimating the breaching process of
landslide dams as triggered by piping.
Keywords
T Technology (General), TA Engineering (General). Civil engineering (General)