Discussion: “Critical Shear Stress of Plates Above the Proportional Limit” (Gerard, George, 1948, ASME J. Appl. Mech., 15, pp. 7–12)

1948 ◽  
Vol 15 (4) ◽  
pp. 386
Author(s):  
E. Z. Stowell
Keyword(s):  
Shear Stress ◽  
Critical Shear Stress ◽  
Proportional Limit

Critical Shear Stress of Plates Above the Proportional Limit

1948 ◽  
Vol 15 (1) ◽  
pp. 7-12
Author(s):  
George Gerard
Keyword(s):  
Shear Stress ◽  
Aluminum Alloys ◽  
Critical Shear Stress ◽  
Experimental Program ◽  
Shear Stresses ◽  
Secant Modulus ◽  
Proportional Limit ◽  
Stress Equation ◽  
Compressive Stresses ◽  
Modulus Method

Abstract The secant-modulus method previously used for determining critical compressive stresses above the proportional limit has been extended for use in determining critical shear stresses above the proportional limit. The method was confirmed by an experimental program designed to check the use of the shear-secant modulus in the critical-shear-stress equation. Nondimensional critical-shear-stress design curves are presented for use with aluminum alloys.

Field evidence of resuspension in a mine tailings pond

2001 ◽  
Vol 38 (4) ◽  
pp. 796-808 ◽  
Author(s):  
Celestina Adu-Wusu ◽  
Ernest K Yanful ◽  
Mohammed H Mian
Keyword(s):  
Shear Stress ◽  
Mine Tailings ◽  
Critical Shear Stress ◽  
Field Measurements ◽  
Shear Stresses ◽  
Wind Speeds ◽  
Tailings Pond ◽  
Field Evidence ◽  
Water Cover ◽  
Solubility Of Oxygen

Flooding of tailings under shallow water covers is an effective method of decommissioning potentially acid generating mine tailings. The low diffusivity and solubility of oxygen in water are attractive features of this technology. However, wind-induced waves can resuspend flooded tailings and expose them to greater contact with dissolved oxygen, thereby increasing the potential for oxidation and acid generation. Field measurements of wind activity and waves under different water cover depths and associated resuspension for a mine tailings pond in Ontario are presented and discussed. The results show that wind speeds greater than 8 m/s above water covers that are shallower than 1 m create waves of height greater than 10 cm and bottom shear stresses greater than 0.2 Pa. Under these conditions the critical shear stress of the mine tailings was exceeded, resulting in erosion and subsequent resuspension.Key words: mine tailings, water cover, wind-induced waves, resuspension, wind speed, shear stress.

ESTIMATION OF CRITICAL SHEAR STRESS OF SEDIMENT USING ROTATIONAL VISCOMETER

2021 ◽  
Vol 77 (2) ◽  
pp. I_1039-I_1044
Author(s):  
Shinya NAKASHITA ◽  
Kyeongmin KIM ◽  
Yuki IMAMURA ◽  
Tadashi HIBINO
Keyword(s):  
Shear Stress ◽  
Critical Shear Stress ◽  
Rotational Viscometer

Experimental Study on Critical Shear Stress of Cohesive Soils and Soil Mixtures

2021 ◽  
Vol 64 (2) ◽  
pp. 587-600
Author(s):  
Xiaojing Gao ◽  
Qiusheng Wang ◽  
Chongbang Xu ◽  
Ruilin Su
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Critical Shear Stress ◽  
Cohesive Soil ◽  
Future Research ◽  
Cohesive Soils ◽  
List Type ◽  
Soil Mixture ◽  
Linear Relationships ◽  
Soil Mixtures

HighlightsErosion tests were performed to study the critical shear stress of cohesive soils and soil mixtures.Linear relationships were observed between critical shear stress and cohesion of cohesive soils.Mixture critical shear stress relates to noncohesive particle size and cohesive soil erodibility.A formula for calculating the critical shear stress of soil mixtures is proposed and verified.Abstract. The incipient motion of soil is an important engineering property that impacts reservoir sedimentation, stable channel design, river bed degradation, and dam breach. Due to numerous factors influencing the erodibility parameters, the study of critical shear stress (tc) of cohesive soils and soil mixtures is still far from mature. In this study, erosion experiments were conducted to investigate the influence of soil properties on the tc of remolded cohesive soils and cohesive and noncohesive soil mixtures with mud contents varying from 0% to 100% using an erosion function apparatus (EFA). For cohesive soils, direct linear relationships were observed between tc and cohesion (c). The critical shear stress for soil mixture (tcm) erosion increased monotonically with an increase in mud content (pm). The median diameter of noncohesive soil (Ds), the void ratio (e), and the organic content of cohesive soil also influenced tcm. A formula for calculating tcm considering the effect of pm and the tc of noncohesive soil and pure mud was developed. The proposed formula was validated using experimental data from the present and previous research, and it can reproduce the variation of tcm for reconstituted soil mixtures. To use the proposed formula to predict the tcm for artificial engineering problems, experimental erosion tests should be performed. Future research should further test the proposed formula based on additional experimental data. Keywords: Cohesive and noncohesive soil mixture, Critical shear stress, Erodibility, Mud content, Soil property.

scholarly journals The impact of particle shape on friction angle and resulting critical shear stress: an example from a coarse-grained, steep, megatidal beach

2013 ◽  
Vol 1 (1) ◽  
pp. 1187-1208 ◽  
Author(s):  
N. Stark ◽  
A. E. Hay ◽  
R. Cheel ◽  
C. B. Lake
Keyword(s):  
Shear Stress ◽  
Particle Motion ◽  
Particle Shape ◽  
Critical Shear Stress ◽  
Friction Angle ◽  
Sediment Dynamics ◽  
Tidal Range ◽  
Strong Increase ◽  
Elliptic Plate ◽  
The Impact

Abstract. The impact of particle shape on the friction angle, and the resulting critical shear stress on sediment dynamics, is still poorly understood. In areas characterized by sediments of specific shape, particularly non-rounded particles, this can lead to large departures from the expected sediment dynamics. The steep slope (1:10) of the mixed sand-gravel beach at Advocate Harbour was found stable in large-scale morphology over decades, despite a high tidal range of ten meters or more, and strong shorebreak action during storms. The Advocate sand (d < 2 mm) was found to have an elliptic, plate-like shape. Exceptionally high friction angles of the material were determined using direct shear, ranging from φ &amp;approx; 41–46°, while the round to angular gravel was characterized by φ = 33°. The addition of 25% of the elliptic sand to the gravel led to an immediate increase of the friction angle to φ = 38°. Furthermore, re-organization of the particles occurred during shearing, being characterized by a short phase of settling and compaction, followed by a pronounced strong dilatory behavior and an accompanying strong increase of shear stress. Long-term shearing (24 h) using a ring shear apparatus led to destruction of the particles without re-compaction. Finally, submerged particle mobilization was simulated using a tilted tray in a tank. Despite a smooth tray surface, particle motion was not initiated until reaching tray tilt angles of 31° and more, being 7° steeper than the latest gravel motion initiation. In conclusion, geotechnical laboratory experiments quantified the important impact of the elliptic, plate-like shape of Advocate Beach sand on the friction angles of both pure sand and sand-gravel mixtures. The resulting effect on initiation of particle motion was confirmed in tilting tray experiments. This makes it a vivid example of how particle shape can contribute to the stabilization of the beachface.

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