Deposition characteristics of debris flows in a lateral flume considering upstream entrainment

Zheng, Hongchao; Shi, Zhenming; Hanley, Kevin J.; Peng, Ming; Guan, Shenggong; Feng, Shi-Jin; Chen, Kunting

doi:10.1016/j.geomorph.2021.107960

Cited by 16 publications

(12 citation statements)

References 59 publications

(89 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In recent years, the occurrence and scale of debris flows have increased significantly due to frequent earthquakes, severe wildfires, volcanic eruptions, and climate change (e.g., Dowling & Santi, 2014; Fan et al., 2019; Gregoretti et al., 2018; Houghton et al., 2001; Pierce et al., 2004; Stoffel et al., 2014). Debris flows can cover floodplains, block rivers and deteriorate the regional ecological environment in the transportation processes (Shi et al., 2018; Takahashi, 2007; Zheng et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

Erosion Mechanisms of Debris Flow on the Sediment Bed

Zheng

Shi

Shao

et al. 2021

Water Resources Research

Self Cite

View full text Add to dashboard Cite

Debris flows are common geological hazards in mountainous regions worldwide. The scale of debris flows can be significantly enhanced by basal erosion and bank collapse in the transportation process, resulting in an increase in casualties and property losses. However, the mechanisms of this growth are largely unclear. Here, we conduct a series of experiments to investigate the erosion of two different bed sediments (coarse‐grained and widely graded) by released flows with three different densities and two different volumes. The erosion mechanisms of bed sediments are revealed by comparing detailed sensor data for flow level, pore pressure and total normal stress. A flow nose develops on the coarse‐grained bed sediment, resulting in a high flow depth and low velocity, while a tabular flow develops on the widely graded bed sediment, leading to a low flow depth and high velocity. The mean erosion rates of the coarse‐grained bed sediment are generally higher than those of the widely graded bed sediment due to significant pore pressure developed in coarse‐grained bed sediment. The feedback effect of bed sediment on the erosion process strongly influences the flow depth and velocity, which in turn affects the mean erosion rate of bed sediment. The interaction between the overlying flow and sediment bed controls the erosion pattern: coarse‐grained bed sediment is eroded by a layer of mass movement whereas widely graded bed sediment is progressively scoured. The interaction between debris flow and bed sediment during erosion is principally attributed to pore‐pressure transmission.

show abstract

Section: Introductionmentioning

confidence: 99%

Erosion Mechanisms of Debris Flow on the Sediment Bed

Zheng

Shi

Shao

et al. 2021

Water Resources Research

Self Cite

View full text Add to dashboard Cite

show abstract

“…Impulse releases of an opaque material from behind a rapidly opening gate have been performed by the USGS (e.g., Iverson et al, 2010) on a large scale with a laterally unconfined runout area or at laboratory scale (e.g., Baselt et al, 2022;Hürlimann et al, 2015). Flows may also be triggered by moving water (e.g., Hotta, 2012;Lanzoni et al, 2017;Lyu et al, 2017;Tsubaki et al, 1983;Zheng et al, 2021). A recirculating flume was used by Armanini et al (2005) to host a long-duration debris flow from which grain-scale measurements of volume fraction and velocity could be taken.…”

mentioning

confidence: 99%

Influence of Pore Fluid on Grain‐Scale Interactions and Mobility of Granular Flows of Differing Volume

et al. 2022

View full text Add to dashboard Cite

The presence of a pore fluid is recognized to significantly increase the mobility of saturated over dry granular flows. However, the mechanisms through which pore fluid increases mobility may not be captured in experimental flows of small volume typical of laboratory conditions. Here we present the results of dry and initially fluid saturated or “wet” experimental flows of near‐monodisperse coarse‐grained ceramic particles in a large laboratory flume for five source volumes of 0.2–1.0 m3. Measurements include flow height, velocity profile, pore pressure, and evolving solid volume fraction, as well as the final deposit shape. The dry experiments constrain the frictional properties of the common granular material and comparison with wet flows permits an independent evaluation of the interstitial fluid effects. These results demonstrate that flow dilation and strong variation in the velocity profile are directly linked to a greatly increased mobility for wet granular flows compared to dry, and a significant influence of scale as controlled by source volume on flow behavior. Excess pore pressure need not be present for these effects to occur.

show abstract

“…The beds composed of silty sands have a stronger tendency to be entrained by debris flow than those of gravels due to the higher frictional resistance of gravels indicated by Eq. ( 17) (Zheng et al, 2021a). By contrast, the reverse tendency holds for unsaturated BeSs.…”

Section: Correlation Between Pore-pressure Evolution and Erosion Typementioning

confidence: 94%

Pore pressure evolution in bed sediment overridden by debris flow: A general formulation

Zheng

Shi

Hanley

et al. 2023

Earth Surf Processes Landf

Self Cite

View full text Add to dashboard Cite

Debris flows can grow dramatically in volume and mobility as they override bed sediment due to the reduction in bed-friction resistance caused by high pore-fluid pressure (PP). However, the mechanisms that control PP evolution in overridden bed sediment are still unclear. Here, a new mathematical model clarifies how diverse styles and magnitudes of PP evolution can result from regulation of the flow diffusion and shear contraction of bed sediment. Normalization of the model equations shows that the propensity for PP generation depends on timescales of PP diffusion and deformation of the bed grains. The PP of saturated bed sediment under immobile conditions is equal to the fluid pressure at the bottom of the flow due to a non-flux basal boundary. However, the PP of unsaturated bed sediment is lower than that of the overlying flow. PP diffusion from a debris flow into an unsaturated bed increases with the bed's permeability and water content. The shear deformation behavior changes from undrained to drained with increasing permeability or decreasing shear velocity of the saturated bed sediment, leading to a reduced magnitude of pore pressure. By contrast, the shear deformation transitions from drained to undrained behavior with increasing permeability and water content of unsaturated bed sediment. The entrainment rate and erosion pattern of bed sediment are closely related to the PP evolution and liquefaction ratio of the bed sediment due to Coulomb-friction shear tractions. Our models can be used to interpret the feedback of PP on the flow momentum during debris-flow entrainment.

show abstract

Deposition characteristics of debris flows in a lateral flume considering upstream entrainment

Cited by 16 publications

References 59 publications

Erosion Mechanisms of Debris Flow on the Sediment Bed

Erosion Mechanisms of Debris Flow on the Sediment Bed

Influence of Pore Fluid on Grain‐Scale Interactions and Mobility of Granular Flows of Differing Volume

Pore pressure evolution in bed sediment overridden by debris flow: A general formulation

Contact Info

Product

Resources

About