1
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Han Z, Ding H, Yan H, Zeng C, Li C, Xie W, Fu B, Li Y. Investigating the bearing performance of the foundation under the combined effects of flood scouring and soaking. Sci Rep 2023; 13:22823. [PMID: 38129679 PMCID: PMC10739836 DOI: 10.1038/s41598-023-50235-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 12/17/2023] [Indexed: 12/23/2023] Open
Abstract
Bearing capacity degradation of foundations under the impact of the flood is one of the major reasons responsible for the collapse and damage to the rural buildings, posing a serious threat to the local village societies. Based on a case study of a rural building foundation had been destroyed by flooding. This paper investigated the deterioration process of rural building foundations under the combined effect of dynamic scouring and static soaking caused by flooding. Using the two-dimensional shallow water equation, erosion depth was calculated for different flood velocities. Then, the bearing capacity degradation under the combined scouring-soaking effect was analyzed using the finite element method. Finally, investigating the influence of inflow direction and building group masking on the foundation's bearing capacity. The results indicate that under the combined effect, the bearing capacity of village building foundations decreases by 47.88%, with scouring slightly more impactful than soaking. Inflow angle has minimal effect on bearing performance, while the masking effect of the building group provides better protection for the foundation of rear buildings.
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Affiliation(s)
- Zheng Han
- School of Civil Engineering, Central South University, 68 Shaoshan Road, Changsha, 410075, Hunan, China
- Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structures, Changsha, 410075, China
| | - Haohui Ding
- School of Civil Engineering, Central South University, 68 Shaoshan Road, Changsha, 410075, Hunan, China
| | - Hongdi Yan
- School of Civil Engineering, Central South University, 68 Shaoshan Road, Changsha, 410075, Hunan, China
| | - Chuicheng Zeng
- School of Civil Engineering, Central South University, 68 Shaoshan Road, Changsha, 410075, Hunan, China
| | - Changli Li
- School of Civil Engineering, Central South University, 68 Shaoshan Road, Changsha, 410075, Hunan, China
| | - Wendu Xie
- School of Civil Engineering, Central South University, 68 Shaoshan Road, Changsha, 410075, Hunan, China
| | - Bangjie Fu
- School of Civil Engineering, Central South University, 68 Shaoshan Road, Changsha, 410075, Hunan, China
| | - Yange Li
- School of Civil Engineering, Central South University, 68 Shaoshan Road, Changsha, 410075, Hunan, China.
- The Key Laboratory of Engineering Structures of Heavy Haul Railway, Ministry of Education, Changsha, 410075, China.
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2
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Wu Y, Ji J, Qi S, Wang X, Li D, Li H, Yang X, Yao Q. Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully. Sci Rep 2023; 13:14894. [PMID: 37689777 PMCID: PMC10492852 DOI: 10.1038/s41598-023-41589-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 08/29/2023] [Indexed: 09/11/2023] Open
Abstract
In recent years, debris flows have frequently erupted in the narrow-steep gully of the earthquake-hit Wenchuan region, displaying high flow velocities and powerful scouring abilities. However, few scouring studies in the narrow-steep gully have been conducted. A model experiment simulated the debris flow scouring process in a narrow-steep flume, in which several important physical parameters, including the debris flow density (ρ), flume slope (θ), and grain size of the sediment (D), were varied to investigate their influences on the erodible strength. The experimental flows were composed of 50 L of water and grains, which scoured 2.3 m of erodible bed down a steeply inclined flume. A high-speed camera photographed the scouring processes, while a 3D laser device captured the final bed shapes. The experiments show that the debris flow first collides with the sediment at the head of the gully to form a pit, which is enlarged by continuous impact; the velocity of the debris flow out of the pit is significantly reduced due to the change in flow direction, resulting in a much lesser scouring effect after the pit; and finally, the gully bed presents the shape of a pit at the entrance and a groove in the middle and rear. The critical scour slope, where the gully bed shows scouring, increases with increasing debris flow density but decreases with increasing grain size of sediment. Following scouring, the maximum scouring depth is further positively correlated with the flume slope. In narrow-steep gullies, the gully bed is extremely susceptible to scouring by debris flow with a low density, and even headward erosion appears, at which the maximum scouring depth only increased from 148.04 to 149.97 mm, but the erosion amount had a significant increase of 36.9%. The research results have an important significance for revealing the disaster-causing phenomena and mechanisms of debris flows in the narrow-steep gully.
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Affiliation(s)
- Yu Wu
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, Sichuan, China
| | - Jiejie Ji
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, Sichuan, China
- Sichuan Water Development Investigation, Design and Research Co., Ltd, Chengdu, 610021, Sichuan, China
| | - Shunchao Qi
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, Sichuan, China
| | - Xiekang Wang
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, Sichuan, China
- Technology innovation center for risk prevention and mitigation of geohazard, Ministry of Natural Resources, Chengdu, 611734, Sichuan, China
| | - Dong Li
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, Sichuan, China
| | - Hongtao Li
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, Sichuan, China
| | - Xingguo Yang
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, Sichuan, China
| | - Qiang Yao
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, Sichuan, China.
- Technology innovation center for risk prevention and mitigation of geohazard, Ministry of Natural Resources, Chengdu, 611734, Sichuan, China.
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3
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Dynamics and runout distance of saturated particle-fluid mixture flow on a horizontal plane: A coupled VOF-DEM study. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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4
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Hierarchical Statistics-Based Nonlinear Vertical Velocity Distribution of Debris Flow and Its Application in Entrainment Estimation. WATER 2022. [DOI: 10.3390/w14091352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The vertical distribution of debris flow profile velocity is the key to studying debris flow, impulse and the sediment carrying process. At present, the linear distribution model based on flume test results cannot describe the vertical distribution of debris flow velocity effectively due to the limitation of measurement methods. In this paper, the smooth particle hydrodynamics (SPH) numerical model based on the Herschel–Bulkley–Papanastasiou (HBP) constitutive model is utilized to invert the three-dimensional dynamic process of debris flow based on a large-scale debris flow flume experiment. With a hierarchical statistical approach, a huge number of particle velocity data were analyzed and processed to obtain the vertical distribution law of velocity. We proposed a nonlinear vertical distribution model of debris flow velocity based on logarithm function accordingly. We also applied the proposed model to the existing debris flow entrainment estimation framework. A flume dam break test case was inverted to verify the performance of erosion calculations. The results show that the numerical simulation results of erosion depth are close to the experimental values. The error percentage of maximum erosion depth is 4.1%. The average error percentage of erosion depth simulation results is 15.5%.
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5
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de Haas T, Nijland W, de Jong SM, McArdell BW. How memory effects, check dams, and channel geometry control erosion and deposition by debris flows. Sci Rep 2020; 10:14024. [PMID: 32820204 PMCID: PMC7441160 DOI: 10.1038/s41598-020-71016-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/30/2020] [Indexed: 11/12/2022] Open
Abstract
Debris flows can grow greatly in size and hazardous potential by eroding bed and bank material, but effective hazard assessment and mitigation is currently hampered by limited understanding of erosion and deposition dynamics. We have collected high-resolution pre- and post-flow topography for 6 debris flows over a 3 km long unconsolidated reach of the Illgraben channel in the Swiss Alps with drone-based photogrammetry. We show that the spatio-temporal patterns of erosion and deposition in debris-flow torrents are highly variable and dynamic. Check dams strongly control the spatial patterns of erosion and deposition. We identify a memory effect where erosion is strong at locations of strong deposition during previous flows and vice versa. Large sediment inputs from subcatchments initially result in new channel erosion through the subcatchment deposits and simultaneous upstream deposition, likely as a result of backwater effects. It is generally believed that erosion increases with debris-flow magnitude, but we show that there is a limit to debris-flow bulking set by channel geometry. These findings provide key guidelines for flow volume forecasting, emphasizing the importance of memory effects and the need to resolve both erosion and deposition in predictive models.
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Affiliation(s)
- T de Haas
- Department of Physical Geography, Universiteit Utrecht, Utrecht, The Netherlands.
| | - W Nijland
- Department of Physical Geography, Universiteit Utrecht, Utrecht, The Netherlands
| | - S M de Jong
- Department of Physical Geography, Universiteit Utrecht, Utrecht, The Netherlands
| | - B W McArdell
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
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6
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Experimental Analysis of Velocity Distribution in a Coarse-Grained Debris Flow: A Modified Bagnold’s Equation. WATER 2020. [DOI: 10.3390/w12051415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Today, Bagnold’s theory is still applied to gravity-driven flows under the assumption of uniform sediment concentration. This study presents findings of flume experiments conducted to investigate the velocity and concentration distributions within the debris body by using high-resolution images. The analysis has shown that the concentration and mobility of grains vary along the depth. A linear law to interpret the grains concentration distribution, starting from the knowledge of the packing concentration and of the surface concentration, Cs, has been identified. By considering such a law, modified expressions of the Bagnold’s number and the velocity in stony-type debris flows are also presented. By using these expressions, three regimes of motion have been identified along the depth, and the velocity profile within the debris body is determined as a function of the parameter Cs. It has been verified that the velocity profiles estimated by using the modified equation compare well (mean square error less than 0.1) with the literature’s measured profiles when Cs is correctly measured or estimated. Results of cutting tests, conducted for a sample of the used material, have also allowed us to verify that Cs could be determined as a function of the static friction angle of the material.
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7
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Glacial Lake Inventory and Lake Outburst Flood/Debris Flow Hazard Assessment after the Gorkha Earthquake in the Bhote Koshi Basin. WATER 2020. [DOI: 10.3390/w12020464] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Glacial lake outburst floods (GLOF) evolve into debris flows by erosion and sediment entrainment while propagating down a valley, which highly increases peak discharge and volume and causes destructive damage downstream. This study focuses on GLOF hazard assessment in the Bhote Koshi Basin (BKB), where was highly developed glacial lakes and was intensely affected by the Gorkha earthquake. A new 2016 glacial lake inventory was established, and six unreported GLOF events were identified with geomorphic outburst evidence from GaoFen-1 satellite images and Google Earth. A new method was proposed to assess GLOF hazard, in which large numbers of landslides triggered by earthquake were considered to enter into outburst floods enlarge the discharge and volume of debris flow in the downstream. Four GLOF hazard classes were derived according to glacial lake outburst potential and a flow magnitude assessment matrix, in which 11 glacial lakes were identified to have very high hazard and 24 to have high hazard. The GLOF hazard in BKB increased after the earthquake due to landslide deposits, which increased by 216.03 × 106 m3, and provides abundant deposits for outburst floods to evolve into debris flows. We suggest that in regional GLOF hazard assessment, small glacial lakes should not be overlooked for landslide deposit entrainment along a flood route that would increase the peak discharge, especially in earthquake-affected areas where large numbers of landslides were triggered.
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8
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Berzi D, Jenkins JT, Richard P. Erodible, granular beds are fragile. SOFT MATTER 2019; 15:7173-7178. [PMID: 31490508 DOI: 10.1039/c9sm01372e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Geophysical flows that involve the transport of grains and the shearing of colloids and non-Brownian suspensions often take place above a substrate composed of the same particles that can be incorporated into the flow. Despite the importance of understanding such erodible beds to the phrasing of appropriate boundary conditions for the solution of continuum models, a rigorous definition of the erodible bed and the constitutive relations for the stresses within it are still lacking. Here, we use discrete-element simulations to show that the intense, intermittent forming and breaking of contact chains marks the transition to the erodible bed at a critical solid volume fraction, as in shear jamming of steady, homogeneous flows. However, the compressible, collisional flow that confines the bed is not strong enough to insure the stability of the contact network, resulting in a bulk stiffness that is three orders of magnitude less than in shear jamming.
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Affiliation(s)
- Diego Berzi
- Department of Civil and Environmental Engineering, Politecnico di Milano, 20133 Milano, Italy.
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9
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Paull CK, Talling PJ, Maier KL, Parsons D, Xu J, Caress DW, Gwiazda R, Lundsten EM, Anderson K, Barry JP, Chaffey M, O'Reilly T, Rosenberger KJ, Gales JA, Kieft B, McGann M, Simmons SM, McCann M, Sumner EJ, Clare MA, Cartigny MJ. Powerful turbidity currents driven by dense basal layers. Nat Commun 2018; 9:4114. [PMID: 30291228 PMCID: PMC6173716 DOI: 10.1038/s41467-018-06254-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/20/2018] [Indexed: 11/09/2022] Open
Abstract
Seafloor sediment flows (turbidity currents) are among the volumetrically most important yet least documented sediment transport processes on Earth. A scarcity of direct observations means that basic characteristics, such as whether flows are entirely dilute or driven by a dense basal layer, remain equivocal. Here we present the most detailed direct observations yet from oceanic turbidity currents. These powerful events in Monterey Canyon have frontal speeds of up to 7.2 m s-1, and carry heavy (800 kg) objects at speeds of ≥4 m s-1. We infer they consist of fast and dense near-bed layers, caused by remobilization of the seafloor, overlain by dilute clouds that outrun the dense layer. Seabed remobilization probably results from disturbance and liquefaction of loose-packed canyon-floor sand. Surprisingly, not all flows correlate with major perturbations such as storms, floods or earthquakes. We therefore provide a new view of sediment transport through submarine canyons into the deep-sea.
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Affiliation(s)
- Charles K Paull
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA.
| | - Peter J Talling
- Departments of Geography and Earth Sciences, Durham University, Lower Mountjoy, South Road, Durham, DH1 3LE, UK.,National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK
| | - Katherine L Maier
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA.,Pacific Coastal and Marine Science Center, U.S. Geological Survey, 2885 Mission Street, Santa Cruz, CA, 95060, USA
| | - Daniel Parsons
- Energy and Environment Institute, University of Hull, Cottingham Road, Hull, HU6 7RX, UK
| | - Jingping Xu
- Department of Ocean Science and Engineering, Southern University of Science and Technology of China, No 1088, Xueyuan Road, Nanshan District, 518055, Shenzhen, Guangdong, China.,Qingdao National Laboratory for Marine Science and Technology, 266061, Qingdao, China
| | - David W Caress
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - Roberto Gwiazda
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - Eve M Lundsten
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - Krystle Anderson
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - James P Barry
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - Mark Chaffey
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - Tom O'Reilly
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - Kurt J Rosenberger
- Pacific Coastal and Marine Science Center, U.S. Geological Survey, 2885 Mission Street, Santa Cruz, CA, 95060, USA
| | - Jenny A Gales
- National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK.,University of Plymouth, Drake Circus, Plymouth, Devon, PL4 8AA, UK
| | - Brian Kieft
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - Mary McGann
- Pacific Coastal and Marine Science Center, U.S. Geological Survey, 345 Middlefield Road, MS999, Menlo Park, CA, 94025, USA
| | - Steve M Simmons
- Energy and Environment Institute, University of Hull, Cottingham Road, Hull, HU6 7RX, UK
| | - Mike McCann
- Monterey Bay Aquarium Research Institute (MBARI), 7700 Sandholdt Rd, Moss Landing, CA, 95039, USA
| | - Esther J Sumner
- Ocean and Earth Science, University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | - Michael A Clare
- National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK
| | - Matthieu J Cartigny
- Departments of Geography and Earth Sciences, Durham University, Lower Mountjoy, South Road, Durham, DH1 3LE, UK.,National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, UK
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10
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Hydrodynamic Characteristics of the Formation Processes for Non-Homogeneous Debris-Flow. WATER 2018. [DOI: 10.3390/w10040452] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Trinh T, Boltenhagen P, Delannay R, Valance A. Erosion and deposition processes in surface granular flows. Phys Rev E 2018; 96:042904. [PMID: 29347464 DOI: 10.1103/physreve.96.042904] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Indexed: 11/07/2022]
Abstract
We report on experiments aiming at characterizing erosion and deposition processes on a tilted granular bed. We investigate the existence of the neutral angle, that is, the critical angle at which erosion exactly balances accretion after the passage of a granular avalanche of a finite mass. Experiments show in particular that the neutral angle depends on both avalanche mass and shape but is rather insensitive to the bed length. This result strongly suggests that the effective friction between the static and mobile granular phases cannot be taken as an intrinsic property that is only material dependent but should be considered a flow-dependent property. Interestingly, for a given avalanche mass, the net erosion rate increases linearly with the angular deviation from the neutral angle. We also compare our data with the predictions of the erosion-deposition model introduced by Bouchaud, Cates, Ravi Prakash, and Edwards (BCRE) [J. Phys. I 4, 1283 (1994)JPGCE81155-430410.1051/jp1:1994195]. We show that the predictions drawn from the modified version of the BCRE model proposed by Boutreux and de Gennes, in which the local erosion rate between the static and mobile phases is independent of the flow thickness, are in remarkable agreement with the experimental results.
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Affiliation(s)
- T Trinh
- Institut de Physique de Rennes, CNRS UMR 6251, Université de Rennes 1, 35042 Rennes Cedex, France
| | - P Boltenhagen
- Institut de Physique de Rennes, CNRS UMR 6251, Université de Rennes 1, 35042 Rennes Cedex, France
| | - R Delannay
- Institut de Physique de Rennes, CNRS UMR 6251, Université de Rennes 1, 35042 Rennes Cedex, France
| | - A Valance
- Institut de Physique de Rennes, CNRS UMR 6251, Université de Rennes 1, 35042 Rennes Cedex, France
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12
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A Free Interface Model for Static/Flowing Dynamics in Thin-Layer Flows of Granular Materials with Yield: Simple Shear Simulations and Comparison with Experiments. APPLIED SCIENCES-BASEL 2017. [DOI: 10.3390/app7040386] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Jenkins JT, Berzi D. Erosion and deposition in depth-averaged models of dense, dry, inclined, granular flows. Phys Rev E 2016; 94:052904. [PMID: 27967100 DOI: 10.1103/physreve.94.052904] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Indexed: 11/07/2022]
Abstract
We derive expressions for the rates of erosion and deposition at the interface between a dense, dry, inclined granular flow and an erodible bed. In obtaining these, we assume that the interface between the flowing grains and the bed moves with the speed of a pressure wave in the flow, for deposition, or with the speed of a disturbance through the contacting particles in the bed, for erosion. We employ the expressions for the rates of erosion and deposition to show that after an abrupt change in the angle of inclination of the bed the characteristic time for the motion of the interface is much shorter than the characteristic time of the flow. This eliminates the need for introducing models of erosion and deposition rate in the mass balance; and the instantaneous value of the particle flux is the same function of the instantaneous value of the flow depth as in a steady, uniform flow.
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14
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Fei M, Sun Q, Xu X, Jin F, Zhou GG. Simulations of multi-states properties of granular materials based on non-linear granular elasticity and the MiDi rheological relation. POWDER TECHNOL 2016. [DOI: 10.1016/j.powtec.2016.07.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Lefebvre G, Merceron A, Jop P. Interfacial Instability during Granular Erosion. PHYSICAL REVIEW LETTERS 2016; 116:068002. [PMID: 26919014 DOI: 10.1103/physrevlett.116.068002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Indexed: 06/05/2023]
Abstract
The complex interplay between the topography and the erosion and deposition phenomena is a key feature to model granular flows such as landslides. Here, we investigated the instability that develops during the erosion of a wet granular pile by a dry dense granular flow. The morphology and the propagation of the generated steps are analyzed in relation to the specific erosion mechanism. The selected flowing angle of the confined flow on a dry heap appears to play an important role both in the final state of the experiment, and for the shape of the structures. We show that the development of the instability is governed by the inertia of the flow through the Froude number. We model this instability and predict growth rates that are in agreement with the experiment results.
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Affiliation(s)
- Gautier Lefebvre
- Surface du Verre et Interfaces, UMR 125 CNRS/Saint-Gobain, 39, quai Lucien Lefranc, F-93303 Aubervilliers, Cedex, France
| | - Aymeric Merceron
- Surface du Verre et Interfaces, UMR 125 CNRS/Saint-Gobain, 39, quai Lucien Lefranc, F-93303 Aubervilliers, Cedex, France
| | - Pierre Jop
- Surface du Verre et Interfaces, UMR 125 CNRS/Saint-Gobain, 39, quai Lucien Lefranc, F-93303 Aubervilliers, Cedex, France
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16
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Luu LH, Philippe P, Chambon G. Experimental study of the solid-liquid interface in a yield-stress fluid flow upstream of a step. Phys Rev E 2015; 91:013013. [PMID: 25679714 DOI: 10.1103/physreve.91.013013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Indexed: 11/07/2022]
Abstract
We present an experimental study investigating the transition zone between a liquid-like unyielded region and a solid-like yielded region in a yield-stress fluid. The configuration consists of a rectangular closed-channel flow disturbed by the presence of a step. Upstream of the step, a solid-liquid interface between a dead zone and a flow zone appears. In this study, we use a model fluid, namely polymer micro-gel Carbopol, which exhibits Herschel-Bulkley viscoplastic rheology. Exploiting the fluid transparency, the flow is monitored by particle image velocimetry using an internal visualization technique. The main outcome of this study is to show that, except in a thin transition layer close to the solid-liquid interface, the flow behaves as an apparent Poiseuille flow with an apparent slip condition at the base. The slip frontier is found to be almost independent of the flow rate while the corresponding slip velocity increases with the flow rate.
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Affiliation(s)
- Li-Hua Luu
- IRSTEA, UR OHAX, 3275 route de Cézanne, 13182 Aix-en-Provence, France
| | - Pierre Philippe
- IRSTEA, UR OHAX, 3275 route de Cézanne, 13182 Aix-en-Provence, France
| | - Guillaume Chambon
- IRSTEA, UR ETGR, Domaine Universitaire, BP 76, 38402 St-Martin-d'Hère, France and Université Grenoble Alpes, 38402 St-Martin-d'Hère, France
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17
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Iverson RM, George DL. A depth-averaged debris-flow model that includes the effects of evolving dilatancy. I. Physical basis. Proc Math Phys Eng Sci 2014. [DOI: 10.1098/rspa.2013.0819] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To simulate debris-flow behaviour from initiation to deposition, we derive a depth-averaged, two-phase model that combines concepts of critical-state soil mechanics, grain-flow mechanics and fluid mechanics. The model's balance equations describe coupled evolution of the solid volume fraction,
m
, basal pore-fluid pressure, flow thickness and two components of flow velocity. Basal friction is evaluated using a generalized Coulomb rule, and fluid motion is evaluated in a frame of reference that translates with the velocity of the granular phase,
v
s
. Source terms in each of the depth-averaged balance equations account for the influence of the granular dilation rate, defined as the depth integral of ∇⋅
v
s
. Calculation of the dilation rate involves the effects of an elastic compressibility and an inelastic dilatancy angle proportional to
m
−
m
eq
, where
m
eq
is the value of
m
in equilibrium with the ambient stress state and flow rate. Normalization of the model equations shows that predicted debris-flow behaviour depends principally on the initial value of
m
−
m
eq
and on the ratio of two fundamental timescales. One of these timescales governs downslope debris-flow motion, and the other governs pore-pressure relaxation that modifies Coulomb friction and regulates evolution of
m
. A companion paper presents a suite of model predictions and tests.
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Affiliation(s)
| | - David L. George
- US Geological Survey, 1300 SE Cardinal Ct. Vancouver, WA 98683, USA
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18
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Lefebvre G, Jop P. Erosion dynamics of a wet granular medium. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:032205. [PMID: 24125259 DOI: 10.1103/physreve.88.032205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Indexed: 06/02/2023]
Abstract
Liquid may give strong cohesion properties to a granular medium, and confer a solidlike behavior. We study the erosion of a fixed circular aggregate of wet granular matter subjected to a flow of dry grains inside a half-filled rotating drum. During the rotation, the dry grains flow around the fixed obstacle. We show that its diameter decreases linearly with time for low liquid content, as wet grains are pulled out of the aggregate. This erosion phenomenon is governed by the properties of the liquids. The erosion rate decreases exponentially with the surface tension while it depends on the viscosity to the power -1. We propose a model based on the force fluctuations arising inside the flow, explaining both dependencies: The capillary force acts as a threshold and the viscosity controls the erosion time scale. We also provide experiments using different flowing grains, confirming our model.
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Affiliation(s)
- Gautier Lefebvre
- Surface du Verre et Interfaces, UMR 125 CNRS/Saint-Gobain, 39, Quai Lucien Lefranc, F-93303 Aubervilliers Cedex, France
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19
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McCoy SW, Kean JW, Coe JA, Tucker GE, Staley DM, Wasklewicz TA. Sediment entrainment by debris flows: In situ measurements from the headwaters of a steep catchment. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jf002278] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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