Measurement of the Apparent Friction Angle During Motion by the High-Speed Ring Shear Apparatus

Viscous grain-grain interaction is an important aspect of the dynamics of oscillating sheetflow. This interaction between sand grains has been investigated qualitatively in a pulsating water tunnel. Furthermore, experiments concerning the interaction between neutrally buoyant spheres in a Couette flow have been carried out at a scale of 100:1 in a new developed ring shear apparatus, called " Carrousel." With respect to the dynamics of sheetflow, in-situ measuring devices for the sand concentration in the sheetflow ("Harp") and the bed load ("Swan") has been developed; some preliminary results are shown. For sand grains, the intrusion depth of sheetflow appears to be of the order of several mm. On high speed video recordings no lateral mixing between grain layers can be observed; for this some physical explanation is given. This supports the modelling of the sheetflow mechanism as moving grain layers.

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Shear Strength Behavior of Sand Reinforced by Kraft Paper Using the Ring Shear Apparatus

Advances in Civil Engineering ◽

10.1155/2021/8819015 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Wan-li Xie ◽

Qianyi Guo ◽

Nelson N.S. Chou ◽

Rongsen Zhu ◽

Maosheng Zhang

Keyword(s):

Shear Plane ◽

Friction Angle ◽

Test Results ◽

Reinforcement Effect ◽

Shear Tests ◽

Kraft Paper ◽

Ring Shear ◽

Strength Behavior ◽

Reinforcement Material ◽

Ring Shear Apparatus

To explore the reinforcement effects of different reinforcement methods, kraft paper was used as reinforcement material, and shear tests were carried out in sand to study the reinforcement effects of kraft paper perpendicular and parallel to the shear plane. The test results show that the two reinforcement methods can effectively improve the strength of sand and the orthogonal reinforcement form is more superior. The existence of reinforced materials greatly improves the cohesion of sand, but does not significantly improve the internal friction angle. The width of reinforcement material has little effect on the reinforcement effect and shows different variation laws under different reinforcement forms.

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Constant-volume friction angle of granular materials

Canadian Geotechnical Journal ◽

10.1139/t88-006 ◽

1988 ◽

Vol 25 (1) ◽

pp. 50-55 ◽

Cited By ~ 57

Author(s):

D. Negussey ◽

W. K. D. Wijewickreme ◽

Y. P. Vaid

Keyword(s):

Phase Transformation ◽

Steady State ◽

Granular Materials ◽

Friction Angle ◽

Confining Pressure ◽

Constant Volume ◽

Ring Shear ◽

Ring Shear Apparatus ◽

Initial Packing ◽

Undrained Shear

The postulate that the constant-volume friction angle [Formula: see text] of a granular material is unique and a function of mineral composition is verified experimentally. Granular materials comprised of particles ranging from minerals to metals are tested in a ring shear apparatus. Test samples are subjected to large shear displacements until a constant lower bound friction angle [Formula: see text] is mobilized. Possible effects of confining pressure, initial packing density, gradation, and particle shape on the value of [Formula: see text] are investigated. Friction angles mobilized in drained shear at the instant of maximum contraction and in undrained shear at phase transformation and steady state are compared with [Formula: see text] values. The experimental results confirm a broader fundamental significance of [Formula: see text] as a material parameter in that it is a consistent minimum drained friction angle equal to friction angles mobilized at phase transformation and steady state in undrained shear. Key words: granular materials, sand, friction angles, constant volume, steady state, phase transformation state, ring shear test.

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