Development of a Modified in situ Direct Shear Test Technique to Determine Shear Strength Parameters of Mine Rock Piles

2008 ◽  
Vol 31 (3) ◽  
pp. 101152 ◽  
Author(s):  
L. D. Suits ◽  
T. C. Sheahan ◽  
A. Fakhimi ◽  
K. Boakye ◽  
D. J. Sperling ◽  
...  
Keyword(s):  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Test Technique

scholarly journals Experimental Study on Variation Law and Mechanism of Soil Shear Strength Parameters along the Slope

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yanhai Wang ◽  
Jianlin Li ◽  
Qiao Jiang ◽  
Yisheng Huang ◽  
Xinzhe Li
Keyword(s):  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Three Gorges Reservoir Area ◽  
Silty Clay ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Undisturbed Soil ◽  
Soil Shear Strength

Under the action of rainwater seepage, geological origin, and human activities, the soil shear strength parameters will have spatial variability along the slope direction. After collecting samples of silty clay at a slope in the Three Gorges Reservoir area as the research object, not only the large-scale direct shear test was carried out on the site but also the direct shear test, water content test, density test, and particle grading analysis test were carried out in the laboratory with the undisturbed soil. The variation law and mechanism of soil shear strength parameters along slope were studied. The results indicate the following: (1) The coefficient of variation of shear strength parameters along the slope is relatively large. With the decrease of the elevation of the test location, the cohesion value tends to be strengthened, while the friction angle tends to degrade. (2) The mechanism of the variation law of soil shear strength parameters along the slope, which is mainly due to the decrease of the elevation, the decrease of the edges and angles between the particles, and the increase of the clay content is determined. (3) The variation model of shear strength parameters along the slope is proposed, which can provide a reference for relevant projects.

Application of In Situ Direct Shear Test for Obtaining Soil Shear Strength Indexes in Projects

2013 ◽  
Vol 788 ◽  
pp. 615-618
Author(s):  
Yu Jun Lu ◽  
Xin Sheng Ge
Keyword(s):  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Soil Condition ◽  
Direct Shear ◽  
Foundation Pit ◽  
Foundation Soil ◽  
Material Resources ◽  
Building Foundation

In order to provide precise shear strength indexes for a building foundation pit supporting project, the second layer and the third layer of foundation soil were in-situ direct shear test. In-situ direct shear test has its own advantages in projects, and it simulates the real soil condition and reflects practical shear strength. But in-situ shear test requires lots of manpower, material resources and financial resources, so it is not convenient to carry out a lot in practical projects.

Effect of weathering on the compressibility and shear strength of a natural clay

2006 ◽  
Vol 43 (6) ◽  
pp. 618-625 ◽  
Author(s):  
Giovanni Gullà ◽  
Maria Clorinda Mandaglio ◽  
Nicola Moraci
Keyword(s):  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Direct Shear ◽  
Test Results ◽  
Natural Clay ◽  
Standard Equipment ◽  
Overconsolidated Clays ◽  
Weathering Process

In situ, seasonal changes expose soils to frequent wetting–drying–freezing–thawing cycles. Such processes can favour and trigger shallow instabilities controlled by the weathering process. This paper presents an experimental study carried out to investigate the effects of the weathering process, caused by the wetting–drying–freezing–thawing cycles, on the compressibility and shear strength of a natural clay. Several specimens were trimmed from block samples of overconsolidated clays taken from a slope in south Calabria, Italy. Specimens were subjected to wetting–drying–freezing–thawing cycles of different durations and then tested with standard equipment (oedometer and direct shear). Test results show that the wetting–drying–freezing–thawing cycles caused a change in the initial microstructure that produced a decrease in the compression index and an increase in the swelling index. Moreover, the direct shear test results show a decrease in the peak shear strength and demonstrate that a larger reduction occurs in the first month of weathering cycles. The intense cycles performed in the laboratory produced a decay of compressibility and a shear strength approaching reconstituted values. The conclusions are important when choosing the shear strength parameters required when studying shallow landsliding in clay slopes.Key words: weathered clay, structure, cycle of degradation, shallow instability.

Effect of Sample Size on TDA Shear Strength Parameters in Direct Shear Tests

2020 ◽  
Vol 2674 (9) ◽  
pp. 1110-1119 ◽  
Author(s):  
Khaled Zahran ◽  
Hany El Naggar
Keyword(s):  
Shear Strength ◽  
Shear Test ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Shear Tests ◽  
Strength Parameters ◽  
Angle Of Internal Friction ◽  
Direct Shear Tests ◽  
Shear Box ◽  
Box Dimensions

Tire-derived aggregate (TDA), a relatively new construction material, has been gaining acceptance as a backfill material for embankments, trenches, and earth-retaining structures because of its lightweight and excellent geotechnical properties. Type A TDA has a basic geometric shape, with particles approximately 12 to 100 mm in size. As a result of the simplicity and accuracy of the direct shear test, most laboratories choose this test in preference to more complex tests. However, TDA requires large-scale direct shear apparatus because of the consistently large size of its particles, and few facilities own this type of apparatus. Depending on the shear box dimensions, the aspect ratio of the particle size to the box dimensions may lead to variations in the shear strength results of the sample being evaluated. This research focuses on studying the effect of TDA sample size on the shear strength results of direct shear tests by using five different shear box sizes. The findings show that the angle of internal friction increases slightly as the dimensions of the shear box decrease. It was found that the maximum variation in the angle of internal friction and the cohesion results of the different shear boxes was only 1.9° and 2.4 kPa, respectively. These differences should be taken into consideration when TDA shear test results are used in the geotechnical design. It is recommended that a shear box with an aspect ratio (W/Dmax) greater than or equal to 4 should be used when evaluating the shear strength parameters of TDA.

Sign in / Sign up

Export Citation Format

Share Document