Particle size effects on coarse soil-geogrid interface response in cyclic and post-cyclic direct shear tests

2016 ◽  
Vol 44 (6) ◽  
pp. 854-861 ◽  
Author(s):  
J. Wang ◽  
F.Y. Liu ◽  
P. Wang ◽  
Y.Q. Cai
Keyword(s):  
Particle Size ◽  
Size Effects ◽  
Direct Shear ◽  
Shear Tests ◽  
Particle Size Effects ◽  
Direct Shear Tests ◽  
Coarse Soil

scholarly journals Influence of particle size and gradation on shear strength–dilation relation of granular materials

2019 ◽  
Vol 56 (2) ◽  
pp. 208-227 ◽  
Author(s):  
Samaneh Amirpour Harehdasht ◽  
Mahmoud N. Hussien ◽  
Mourad Karray ◽  
Varvara Roubtsova ◽  
Mohamed Chekired
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Shear Strength ◽  
Granular Materials ◽  
Plane Strain ◽  
Computer Code ◽  
Direct Shear ◽  
Shear Tests ◽  
Empirical Formulas ◽  
Direct Shear Tests

Upon close scrutiny of data reported in the literature, taking into account particle-scale characteristics to optimize the precision of the well-known empirical Bolton’s equations and imposing particle-size limits on them is recommended. The present paper examines the potential influence of particle size and grading on the shear strength–dilation relation of granular materials from the results of 276 symmetrical direct shear tests. The applicability of physical symmetrical direct shear tests to interpret the plane strain frictional shearing resistance of granular materials has been widely discussed using the discrete element method (DEM) computer code SiGran. Sixteen different grain-size distribution curves of three different materials were tested at different normal pressures and initial relative densities. It is demonstrated that while the contribution of dilatancy to shear strength is not influenced by the variation in the coefficient of uniformity, Cu, in the investigated range, it significantly decreases with increasing mean particle size, D50. The coefficients of Bolton’s equations have been, therefore, adjusted to account for D50. A comparison of the predictions by the proposed empirical formulas with plane strain friction angle, [Formula: see text], and dilation angle, ψ, data from the literature shows that accounting for the grain size yields more accurate results.

scholarly journals Contribution of Particles Size Ranges to Sand Friction

2013 ◽  
Vol 3 (4) ◽  
pp. 497-501 ◽  
Author(s):  
E. Mostefa Kara ◽  
M. Meghachou ◽  
N. Aboubekr
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Granular Material ◽  
Physical Properties ◽  
Friction Angle ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Marine Sand

This work studies the correlation between certain physical properties of granular material such as the friction angle and the grain size distribution. In the laboratory, the determination of friction angle requires hard and expensive testing. Prediction of this parameter from the grading curve proves to be very interesting. Direct shear tests were performed on actual marine sand of Tergha (Algeria) and on seventeen different samples arranged from the same sand with various particle size ranges. Results showed that the friction angle of sand is a result of contribution of various constituent granular classes.

scholarly journals Determination of the Effect of Soil Particle Size Distribution on the Shear Behavior of Sand

2021 ◽  
Vol 5 (2) ◽  
pp. 125
Author(s):  
Mohammad Afrazi ◽  
Mahmoud Yazdani
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Particle Sizes ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests

Many geotechnical problems require the determination of soil engineering properties such as shear strength. Therefore, the determination of the reliable values for this parameter is essential. For this purpose, the direct shear test, as one of the oldest tests to examine the shear strength of soils, is the most common way in laboratories to determine the shear parameters of soil. There are far too many variables that influence the results of a direct shear test. In this paper, a series of 10 × 10 cm direct shear tests were carried out on four different poorly graded sands with different particle size distributions to determine their shear behaviors. Four different poorly graded sands with a different median diameter or medium value of particle size distribution (D50) (0.2, 0.53, 1.3, and 2.3 mm) has been selected, and about 40 direct shear tests were conducted. It was concluded that a soil’s friction angle is affected by coarse-grained material. Accordingly, sandy soils with bigger particle sizes record a higher friction angle than soils containing small particles. The investigations also showed that sand with bigger particle sizes has a higher dilation angle. In addition, a non-linear regression analysis was performed to establish the exact relationship between the friction angle of the soil and the characteristics of the soil particles. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

scholarly journals Experimental Study on the Reliability of Scaling Down Techniques Used in Direct Shear Tests to Determine the Shear Strength of Rockfill and Waste Rocks

CivilEng ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 35-50
Author(s):  
Akram Deiminiat ◽  
Li Li
Keyword(s):  
Experimental Study ◽  
Particle Size ◽  
Shear Strength ◽  
Friction Angle ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Field Samples ◽  
Waste Rocks ◽  
Scaling Down

The determination of shear strength parameters for coarse granular materials such as rockfill and waste rocks is challenging due to their oversized particles and the minimum required ratio of 10 between the specimen width (W) and the maximum particle size (dmax) of tested samples for direct shear tests. To overcome this problem, a common practice is to prepare test samples by excluding the oversized particles. This method is called the scalping scaling down technique. Making further modifications on scalped samples to achieve a specific particle size distribution curve (PSDC) leads to other scaling down techniques. Until now, the parallel scaling down technique has been the most popular and most commonly applied, generally because it produces a PSDC parallel and similar to that of field material. Recently, a critical literature review performed by the authors revealed that the methodology used by previous researchers to validate or invalidate the scaling down techniques in estimating the shear strength of field materials is inappropriate. The validity of scaling down techniques remains unknown. In addition, the minimum required W/dmax ratio of 10, stipulated in ASTM D3080/D3080M-11 for direct shear tests, is not large enough to eliminate the specimen size effect (SSE). The authors’ recent experimental study showed that a minimum W/dmax ratio of 60 is necessary to avoid any SSE in direct shear tests. In this study, a series of direct shear tests were performed on samples with different dmax values, prepared by applying scalping and parallel scaling down techniques. All tested specimens had a W/dmax ratio equal to or larger than 60. The test results of the scaled down samples with dmax values smaller than those of field samples were used to establish a predictive equation between the effective internal friction angle (hereafter named “friction angle”) and dmax, which was then used to predict the friction angles of the field samples. Comparisons between the measured and predicted friction angles of field samples demonstrated that the equations based on scalping scaling down technique correctly predicted the friction angles of field samples, whereas the equations based on parallel scaling down technique failed to correctly predict the friction angles of field samples. The scalping down technique has been validated, whereas the parallel scaling down technique has been invalidated by the experimental results presented in this study.

scholarly journals Sand- and Clay-Photocured-Geomembrane Interface Shear Characteristics Using Direct Shear Test

2021 ◽  
Vol 13 (15) ◽  
pp. 8201
Author(s):  
Lihua Li ◽  
Han Yan ◽  
Henglin Xiao ◽  
Wentao Li ◽  
Zhangshuai Geng
Keyword(s):  
Soil Surface ◽  
Friction Angle ◽  
Direct Shear ◽  
Tensile Crack ◽  
Shear Tests ◽  
Interface Shear ◽  
Direct Shear Tests ◽  
Carbon Black Powder ◽  
Shear Characteristics ◽  
Impermeable Layer

It is well known that geomembranes frequently and easily fail at the seams, which has been a ubiquitous problem in various applications. To avoid the failure of geomembrane at the seams, photocuring was carried out with 1~5% photoinitiator and 2% carbon black powder. This geomembrane can be sprayed and cured on the soil surface. The obtained geomembrane was then used as a barrier, separator, or reinforcement. In this study, the direct shear tests were carried out with the aim to investigate the interfacial characteristics of photocured geomembrane–clay/sand. The results show that a 2% photoinitiator has a significant effect on the impermeable layer for the photocured geomembrane–clay interface. As for the photocured geomembrane–sand interface, it is reasonable to choose a geomembrane made from a 4% photoinitiator at the boundary of the drainage layer and the impermeable layer in the landfill. In the cover system, it is reasonable to choose a 5% photoinitiator geomembrane. Moreover, as for the interface between the photocurable geomembrane and clay/sand, the friction coefficient increases initially and decreases afterward with the increase of normal stress. Furthermore, the friction angle of the interface between photocurable geomembrane and sand is larger than that of the photocurable geomembrane–clay interface. In other words, the interface between photocurable geomembrane and sand has better shear and tensile crack resistance.

Adsorption mechanism of two pesticides on polyethylene and polypropylene microplastics: DFT calculations and particle size effects

2021 ◽  
Vol 291 ◽  
pp. 118120
Author(s):  
Qiming Mo ◽  
Xingjian Yang ◽  
Jinjin Wang ◽  
Huijuan Xu ◽  
Wenyan Li ◽  
...  
Keyword(s):  
Particle Size ◽  
Dft Calculations ◽  
Size Effects ◽  
Adsorption Mechanism ◽  
Particle Size Effects

Particle size effects in the selective hydrogenation of cinnamaldehyde over supported palladium catalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75541-75551 ◽  
Author(s):  
Feng Jiang ◽  
Jian Cai ◽  
Bing Liu ◽  
Yuebing Xu ◽  
Xiaohao Liu
Keyword(s):  
Particle Size ◽  
Size Effect ◽  
Selective Hydrogenation ◽  
Size Effects ◽  
Palladium Catalysts ◽  
Particle Size Effect ◽  
Particle Size Effects ◽  
Supported Palladium Catalysts ◽  
Supported Palladium ◽  
Palladium Particles

Palladium particles of different sizes obtained directly and indirectly by various methods were studied to clarify the particle size effect in the selective hydrogenation of cinnamaldehyde (CAL).

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