首页|How strain- and strain-rate- weakening of rupture-surface strength affects rapid landslides explored through numerical models of the 2009 Jiweishan rock avalanche
How strain- and strain-rate- weakening of rupture-surface strength affects rapid landslides explored through numerical models of the 2009 Jiweishan rock avalanche
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NSTL
Elsevier
? 2022Rapid sliding in a rock avalanche may occur from strain- and strain-rate- weakening of the rupture-surface strength. However, existing research on rock-avalanche dynamics pays little attention to rupture-surface weakening. In this paper, we used high-speed-friction tests on limestone and shale of the Qixia Formation to determine strain- and strain-rate- weakening of the rupture surface of the Jiweishan rock avalanche. The strain- and strain-rate- weakening model inferred that the friction coefficient of the rupture surface decreased rapidly to a residual value of <0.1 within a short interval after rock-avalanche failure, which was collectively determined by shear rate and shear displacement. We used this rate-weakening in a numerical model to investigate the dynamics of the rock avalanche, and compared it with another model that used a constant value of friction. Our model results suggested that rupture-surface weakening could cause the disintegration of the sliding body and influence the post-failure motion of the Jiweishan rock avalanche. With strain- and strain-rate- weakening, a larger sliding-out velocity (~ 13–27 m/s) of the rock mass was modelled due to reduction of frictional energy consumption causing by rupture-surface weakening. Hence a strain and strain-rate- weakened rock mass could both fly farther in the air and strike the ground at a lower angle maintaining more kinetic energy. The transport distance of such a sliding rock mass would have been ~50–500 m longer than in a model without weakening. Our study suggested that strain- and strain-rate- weakening behavior of a rupture surface would significantly increase the rock-avalanche transport distance. Use of such a model might provide more accurate prediction of the disaster reach of rock avalanches.
NSTL
Elsevier
