Effect of Clayey Fine Content on Cyclic Deformative Pullout Behavior of PET Geogrid Embedded in Pure Sand

Abstract. This paper presents a Discrete Element-based elasto-plastic-adhesive model which is adapted and tested for producing hillslope debris flows. The numerical model produces three phases of particle contacts: elastic, plastic and adhesion. The model capabilities of simulating different types of cohesive granular flows were tested with different ranges of flow velocities and heights. The basic model parameters, being the basal friction (&varphi;b) and normal restitution coefficient (&varepsilon;n), were calibrated using field experiments of hillslope debris flows impacting two sensors. Simulations of 50 m3 of material were carried out on a channelized surface that is 41 m long and 8 m wide. The calibration process was based on measurements of flow height, flow velocity and the pressure applied to a sensor. Results of the numerical model matched well those of the field data in terms of pressure and flow velocity while less agreement was observed for flow height. Those discrepancies in results were due in part to the deposition of material in the field test which are not reproducible in the model. A parametric study was conducted to further investigate that effect of model parameters and inclination angle on flow height, velocity and pressure. Results of best-fit model parameters against selected experimental tests suggested that a link might exist between the model parameters &varphi;b and &varepsilon;n and the initial conditions of the tested granular material (bulk density and water and fine contents). The good performance of the model against the full-scale field experiments encourages further investigation by conducting lab-scale experiments with detailed variation of water and fine content to better understand their link to the model's parameters.

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Chemical composition and fiber properties of fast-growing species in Latvia and its potential for forest bioindustry

Forestry Studies / Metsanduslikud Uurimused ◽

10.1515/fsmu-2017-0004 ◽

2017 ◽

Vol 66 (1) ◽

pp. 27-32 ◽

Cited By ~ 1

Author(s):

Inese Sable ◽

Uldis Grinfelds ◽

Laura Vikele ◽

Linda Rozenberga ◽

Dagnija Lazdina ◽

...

Keyword(s):

Chemical Composition ◽

Kraft Pulp ◽

Lignin Content ◽

Lodgepole Pine ◽

Pulp Yield ◽

Fine Content ◽

Fast Growing ◽

Pulp Fibres ◽

Global Energy Supply ◽

Fast Growing Species

AbstractBioenergy, including energy from wood, currently provides about 9–13% of the total global energy supply. Every fibre of fast-growing wood has a value for its potential use as a material in both pulp and paper and wood chemical industries. The aim of this study was to assess the chemical composition and fibre’s properties of fast-growing species in Latvia – aspen, hybrid aspen, lodgepole pine, poplar and willow. Results showed a variation of cellulose, lignin, extractives and ash contents among the species. Kraft pulp yield and amount of residual lignin were measured and properties of pulp fibres determined. Form factor and fine content in pulp were measured. Poplar and aspen wood had the highest content of cellulose, while lodgepole pine had the highest lignin content in wood and the longest kraft pulp fibres. Willow had 20% of fines in pulp. Individual results suggest the most suitable application of each species.

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Closure to “Effect of Particle Shape and Fine Content on the Behavior of Binary Mixture” by Tang-Tat Ng, Wei Zhou, and Xiao-Lin Chang

Journal of Engineering Mechanics ◽

10.1061/(asce)em.1943-7889.0001324 ◽

2017 ◽

Vol 143 (9) ◽

pp. 07017004 ◽

Cited By ~ 1

Author(s):

Tang-Tat Ng ◽

Wei Zhou ◽

Xiao-Lin Chang

Keyword(s):

Binary Mixture ◽

Particle Shape ◽

Fine Content

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Time-dependent behaviour of sand with different fine contents under oedometric loading

Canadian Geotechnical Journal ◽

10.1139/cgj-2017-0565 ◽

2019 ◽

Vol 56 (1) ◽

pp. 102-115 ◽

Cited By ~ 1

Author(s):

Friedrich Levin ◽

Stefan Vogt ◽

Roberto Cudmani

Keyword(s):

Strain Rate ◽

Creep Behaviour ◽

Silty Sand ◽

Granular Soils ◽

Rate Dependency ◽

Viscous Effects ◽

Fine Content ◽

Constant Rate ◽

Rate Controlled ◽

Strain Rate Dependency

To characterize the effects of creep, strain rate, and relaxation in granular soils, different sands have been studied under oedometric loading. The tests were analysed in the framework of the isotache concept. The results show increasing creep rates with increasing vertical stresses and a strong reduction of the creep rate upon unloading. A lower void ratio leads to less creep. Evaluation of the ratio Cα/Cc, where Cα is the creep coefficient and Cc is the compression index, demonstrates considerable deviation from a constant soil-specific value for the sands. With increasing fine content, however, a constant soil-specific ratio has been found for a silty sand. In strain rate–controlled tests, a sand with low and a sand with significant content of nonplastic fines were compared. Constant rate of strain tests displayed practically no strain rate dependency for the sand with little fines and a well visible strain rate dependency for the very silty sand. Tests with stepwise change of strain rate showed non-isotache behaviour for the sand with little fines and isotache behaviour for the other. Stress-relaxation tests displayed an isochronous behaviour. The analysis of the three viscous effects in sands showed they cannot altogether be mathematically described in the framework of the isotache concept. A new compression model for the creep behaviour of sands is presented.

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Chemometric Optimisation of a Copper Sulphide Tailings Flocculation Process in the Presence of Clays

Minerals ◽

10.3390/min9100582 ◽

2019 ◽

Vol 9 (10) ◽

pp. 582 ◽

Cited By ~ 10

Author(s):

Claudia Castillo ◽

Christian F. Ihle ◽

Ricardo I. Jeldres

Keyword(s):

Settling Rate ◽

Mixing Conditions ◽

Fine Content ◽

Operational Conditions ◽

Coarse Aggregates ◽

Series Of Experiments ◽

Sulphide Tailings ◽

Solids Content ◽

Two Stages ◽

Flocculation Process

The presence of fine and ultra-fine gangue minerals in flotation plants can contribute to sub-optimal valuable ore recovery and incomplete water recycling from thickeners, with the performance of the latter equipment relying on adequate flocculation. In order to study the dependence of the flocculation process on the suspension-flocculant mixing conditions, a series of experiments—chosen using chemometric analysis—were carried out by varying mixing conditions, solid concentration, water salinity and flocculant dosage. To this purpose, two different tailings (both featuring coarse and fine content) were considered and a response surface methodology based on a Doehlert experimental design was used. The results suggest that the operational conditions to optimise the flocculated tailings settling rate and the suspended solids that report to a thickener overflow are not necessarily the same. This is a reasonable outcome, given that the settling rate depends on the coarse aggregates generated in the slurry, while the overflow solids content is governed both by either fine particle content (and its characteristics) or small aggregates. It is inferred that to maximise dewatering performance two stages should be involved—a separate treatment of the thickener overflow to remove fine content and thickening at optimal flocculant dosage to enhance this process.

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On the influence of the spatial distribution of fine content in the hydraulic conductivity of sand-clay mixtures

Earth Sciences Research Journal ◽

10.15446/esrj.v22n4.69332 ◽

2018 ◽

Vol 22 (4) ◽

pp. 239-249 ◽

Cited By ~ 1

Author(s):

William Mario Fuentes ◽

Carolina Hurtado ◽

Carlos Lascarro

Keyword(s):

Spatial Distribution ◽

Hydraulic Conductivity ◽

Numerical Model ◽

Soil Sample ◽

Gaussian Distribution ◽

Geotechnical Engineering ◽

Empirical Relation ◽

Fine Content ◽

The Mean

Sand-clay mixtures are one of the most usual types of soils in geotechnical engineering. These soils present a hydraulic conductivity which highly depends on the fine content. In this work, it will be shown, that not only the mean fine content of a soil sample affects its hydraulic conductivity, but also its spatial distribution within the sample. For this purpose, a set of hydraulic conductivity tests with sand-clay mixtures have been conducted to propose an empirical relation of the hydraulic conductivity depending on the fine content. Then, a numerical model of a large scaled hydraulic conductivity test is constructed. In this model, the heterogeneity of the fine content is simulated following a Gaussian distribution. The equivalent hydraulic conductivity resulting of the whole model is then computed and the influence of the spatial distribution of the fine content is evaluated. The results indicate that the hydraulic conductivity is not only related to the mean fine content, but also on its heterogeneity.

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Maximum dry density of sand–kaolin mixtures predicted by using fine content and specific gravity

SN Applied Sciences ◽

10.1007/s42452-020-03481-9 ◽

2020 ◽

Vol 2 (10) ◽

Author(s):

Badee Alshameri

Keyword(s):

Specific Gravity ◽

Dry Density ◽

Maximum Dry Density ◽

Fine Content

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Variation of uplift pressure of debris flow on the dam bottom

10.5194/egusphere-egu2020-5382 ◽

2020 ◽

Author(s):

Xingzhang Chen ◽

Hui Chen

Keyword(s):

Debris Flow ◽

Time Lag ◽

Temporal Variations ◽

Flow Density ◽

Flume Experiments ◽

Fine Content ◽

Dam Foundation ◽

Uplift Pressure ◽

Average Value ◽

The Stability

<p>Abstract: Uplift pressure is crucial for the stability of debris flow dam because of its reducing the effective pressure on the dam foundation and the anti-slide force of the dam. This study investigates the spatial and temporal variations of the uplift pressures during the debris flow impact processes, through a series of flume experiments. Before the debris flow impacting on the dam, the uplift pressure keeps stable due to the steady water level, and then it decreases slightly at the instant of debris flow impacting on the dam which lasts for no more than 1 s, and then increases sharply within a time lag no more than 2 s, and then decreases sharply soon afterwards. The maximal increasing ratio is 6.4 and the average value is 3, comparing with the uplift pressure before the impacting. The peak pressure occurs before the dam and decreases with the distance from the dam with a nearly linear tendency. The increment of uplift pressure also presents a similar tendency with the distance from the dam. In addition, the uplift pressure is found to be strongly influenced by the permeability of debris flow deposits, especially by the fine content of grain composition, and by the properties of the flow, such as the flow density, runoff volume and hydraulic gradient, and the pressure rises in a nearly linear form with the properties.</p><p>Keywords: debris flow, uplift pressure, check dam, flume experiments</p>

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