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Landslides - The frictional resistance of rock and debris is supposed to induce stress anisotropy in the unsteady, non-uniform flow of gravitational mass flows, including debris flows. Though... 相似文献
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Collins M.D. Ali H.B. Authement M.J. Nagl A. Uberall H. Miller J.F. Arvelo J.I. 《Oceanic Engineering, IEEE Journal of》1988,13(4):235-244
The effects of refracting sediments on low-frequency sound propagation in range-dependent oceans are studied with parabolic equation models. The predictions of three sediment sound-speed models for low-frequency propagation are compared. Two factors that result in sediment sound-speed gradients are considered. Variation in static pressure due to the variation in the weight of overlying material causes sediment sound speed to increase with depth. The thermodynamic influence of the ocean results in large sound-speed gradients in a boundary layer in the uppermost layer of the sediment. The associated affects of attenuation on propagation are also considered. Both time-domain and frequency-domain results are presented 相似文献
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The internal deformation within debris flows holds essential information on dynamics and flow resistance of such mass-wasting processes. Systematic measurements of velocity profiles in real-scale debris flows are not yet available. Additionally, data on basal stresses of the solid and the fluid phase are rare. Here, we present and analyse measurements of vertical velocity profiles in two debris flows naturally occurring in the Gadria Creek, Italy. The method is based on cross-correlation of paired conductivity signals from an array of sensors installed on a fin-shaped wall located in the middle of the channel. Additionally, we measure normal stress and pore fluid pressure by two force plates with integrated pressure transducers. We find internal deformation throughout the flows. Only at the very front was some en-bloc movement observed. Velocity profiles varied from front to tail and between flows. For one debris flow, pore fluid pressure close to normal stress was measured, whereas the other flow was less liquefied. The median shear rates were mostly less than 5 s−1 and Savage numbers at the basal layer ranged from 0.01 to 1. Our results highlight the variable nature of debris flows and provide quantitative data on shear rate and basal stress distribution to help guide model development for hazard assessment and landscape evolution. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. 相似文献
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