Analysis of mobilized stress ratio of gap-graded granular materials in direct shear state considering coarse fraction effect

2021 ◽  
Author(s):  
X. S. Shi ◽  
Kai Liu ◽  
Jianhua Yin
Keyword(s):  
Granular Materials ◽  
Stress Ratio ◽  
Coarse Fraction ◽  
Direct Shear ◽  
Shear State

scholarly journals Frictional properties between geocells filled with granular material

2021 ◽  
Vol 20 (2) ◽  
pp. 332-345
Author(s):  
Gökhan Altay ◽  
◽  
Cafer Kayadelen ◽  
Taha Taskiran ◽  
Baki Bagriacik ◽  
...  
Keyword(s):  
Granular Material ◽  
Normal Stress ◽  
Granular Materials ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Frictional Properties ◽  
Geotechnical Structures ◽  
Series Of Experiments ◽  
Restricted Volume

The parameters concerning the interaction between geocell and granular materials is required for the design of many geotechnical structures. With this in mind, a series of experiments using simple direct shear tests are conducted in order to understand the frictional properties between geocells filled with granular materials. The 54 test samples are prepared by filling the geocell with granular materials having three different gradations. These samples are tested at three different relative densities under three different normal stress levels. As a result, it was observed that interface resistance between the geocells filled with granular material is found to be generally greater than in the samples without geocells. Additionally, these samples with geocells are found to be stiffer; this is due to the fact that the samples with geocell gained more cohesion because geocells confined the grains within a restricted volume.

The influence of particle elongations on direct shear behaviour of granular materials using DEM

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Shiva Prashanth Kumar Kodicherla ◽  
Guobin Gong ◽  
Z. X. Yang ◽  
Kristian Krabbenhoft ◽  
Lei Fan ◽  
...  
Keyword(s):  
Granular Materials ◽  
Shear Behaviour ◽  
Direct Shear

Micromechanical behavior of granular materials in direct shear modeling

2015 ◽  
Vol 38 (4) ◽  
pp. 469-480 ◽  
Author(s):  
Wen-Chao Huang ◽  
Chiu-Yen Sung ◽  
Hung-Yun Liao ◽  
Sheng-Shin Chu
Keyword(s):  
Granular Materials ◽  
Direct Shear

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.

Influence of stress history on the strength parameters of an unsaturated statically compacted soil

1999 ◽  
Vol 36 (2) ◽  
pp. 251-261 ◽  
Author(s):  
Tomoyoshi Nishimura ◽  
Yasunari Hirabayashi ◽  
Delwyn G Fredlund ◽  
Julian K-M Gan
Keyword(s):  
Shear Strength ◽  
Unsaturated Soil ◽  
Stress Ratio ◽  
Matric Suction ◽  
Strength Parameter ◽  
Direct Shear ◽  
State Variables ◽  
Total Stress ◽  
Stress History ◽  
Compacted Soil

Unsaturated soils are generally near the ground surface and are commonly overconsolidated due to environmental effects. The stress state variables for an unsaturated, in situ profile consist of the net total stress, (σ - ua), and matric suction, (ua - uw), where σ is the total stress (in three directions), ua is the pore-air pressure, and uw is the pore-water pressure. These stress state variables control the behavior of the unsaturated soil. A total stress ratio, TSR, was used in this study as a measure of the stress history. The total stress ratio is defined as the ratio of the compaction pressure to the current confining pressure. Shear tests were conducted using a modified direct shear apparatus on a statically compacted unsaturated soil subjected to various total stress ratios with controlled matric suction. The shear strength parameters (i.e., ϕ', ϕb, and c') for an unsaturated soil were measured using the modified direct shear apparatus. The total stress ratio influences the shear strength parameter ϕb of a compacted soil. The shear strength parameter ϕb decreases with matric suction regardless of the loading history. For a compacted soil with a total stress ratio of 1.0, ϕb was higher than that for the soil tested at a total stress ratio greater than 1.0, regardless of increase in matric suction, and was shown to be influenced by loading history.Key words: unsaturated soil, shear strength, stress history, compacted soil, direct shear test, matric suction.

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