Effect of Grain Size and Specimen Dimension on Triaxial Shear Strength Parameters of Coarse Soil

2014 ◽  
Vol 926-930 ◽  
pp. 557-560
Author(s):  
Saman Asreazad

The triaxial shear strength of two specimen sizes of poorly-graded gravelly sand mixtures (SF) after removing a portion of the coarse aggregate by method called scalped gradation was investigated. The lower shear strength parameters obtained from small specimens for coarse soils in triaxial testing can lead to uneconomic design. In order to reduce testing costs and utilize more economic designs for coarse soils, small specimens can be used instead of large specimens; in addition, the test results can be corrected. The correlation of the triaxial test results of the two different size specimens was evaluated in this paper.

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yao Xiao ◽  
Huafeng Deng ◽  
Jingcheng Fang ◽  
Hengbin Zhang ◽  
Jianlin Li

The results obtained from the mechanical test of rock samples inevitably suffer dispersion owing to discrepancies between test specimens. In view of these deficiencies, the present study proposes a method based on the empirical equation of shear strength developed by Barton to determine the shear strength parameters of joint surfaces using a single test specimen. This approach is then applied to optimize the analysis of multiple specimens. An analysis of experimental results verifies that the shear strength parameters of joint surfaces obtained by the proposed method can more accurately reflect the shear mechanics of multiple specimens than conventional multiple sample analyses; meanwhile, the results are reasonable and reliable. More importantly, the optimized method ensures the shear strength parameters are no longer affected by the sequence of specimens employed during shear test. The optimized analysis method eliminates the effect of differences between specimens and the influence of subjective factors on test results and therefore provides more realistic evaluations of shear strength parameters.


2012 ◽  
Vol 256-259 ◽  
pp. 358-361
Author(s):  
Xiang Yun Kong ◽  
Guang Jin Wang ◽  
Xiao Chao Zhou

Apparent particle size grading is the important characteristic of super-high bench dumping site, and the critical factors with the impact of its stability and disaster prevention are the fragmentation distribution and shear strength parameters of granular. With the copper mine dumping site which had the feature of apparent particle size grading, the thesis carried out the study of on-site particle size investigation and indoor laboratory. The particle-size distribution law with the changing of dumping-site height was analyzed and quantitative relationship between the fragmentation distribution and shear strength parameters of granular was discussed. The research results indicated that coarse-grain contents and maximum grain size were increased significantly according to the decreasing of dumping-site height, which showed that the dumping-site had the feature of apparent particle size grading. The coarse particle content in the grain size composition and internal friction angle φ of shear strength parameters increased with the obvious increment of the distribution value B. The relationship between distribution value B and the internal friction angle φ could be expressed by exponential function curve.


1974 ◽  
Vol 11 (1) ◽  
pp. 59-71 ◽  
Author(s):  
W. S. Freeman ◽  
Hugh B. Sutherland

Two major aspects of an investigation dealing with the stability of natural and cut slopes in the Winnipeg area are described. The first concerns an experimental investigation of the anisotropic shear strength characteristics of the layered Lake Agassiz clays and the second is a study of the mechanism of failure for slopes in these layered clays.Four main types of clay were investigated and it was found that the effective shear strength parameters were greater for failure across the layers than for failure along the layers. Residual shear strength parameters were also determined.Stability analyses were carried out for representative slope cross sections using circular and noncircular failure surfaces, taking into account the anisotropic shear strength effects measured in the laboratory tests.Factors of safety were found for the conventional method of analysis assuming circular arc failure surfaces and isotropic shear strength properties. These factors of safety were found to be up to 0.5 greater than those obtained from noncircular failure surfaces which partially passed along the layers and so mobilized the lower shear strength properties of these layers.


2019 ◽  
Vol 92 ◽  
pp. 07007 ◽  
Author(s):  
Yong Wang ◽  
Wanli Xie ◽  
Guohong Gao

This paper discussed the effect of moisture content on shear strength of loess during different confining pressure firstly. The variation law of deformation parameters, i.e. shear strength and secant modulus is analysed in detail. The results show that moisture content is the dominant factor of shear strength of Loess, with the increase of water content, the strength parameters levelled down, and there is a linear relationship between them to a certain extent. Compared with confining pressure, the effect of water content on shear strength is more obvious. In addition, triaxial test under different drainage conditions were carried out, namely, consolidated drained(CD) test and consolidated undrained(CU) test. Results indicate that the shear damage characteristics are similar during the two test methods.


2017 ◽  
Vol 39 (4) ◽  
pp. 3-15 ◽  
Author(s):  
Leyla Bouaricha ◽  
Ahmed Djafar Henni ◽  
Laurent Lancelot

Abstract A study was undertaken to investigate the shear strength parameters of treated sands reinforced with randomly distributed glass fibers by carrying out direct shear test after seven days curing periods. Firstly, we studied the fiber content and fiber length effect on the peak shear strength on samples. The second part gives a parametric analysis on the effect of glass fiber and clinker residue content on the shear strength parameters for two types of uniform Algerian sands having different particle sizes (Chlef sand and Rass sand) with an average relative density Dr = 50%. Finally, the test results show that the combination of glass fiber and clinker residue content can effectively improve the shear strength parameters of soil in comparison with unreinforced soil. For instance, there is a significant gain for the cohesion and friction angle of reinforced sand of Chlef. Compared to unreinforced sand, the cohesion for sand reinforced with different ratios of clinker residue increased by 4.36 to 43.08 kPa for Chlef sand and by 3.1 to 28.64 kPa for Rass sand. The feature friction angles increased from 38.73° to 43.01° (+4.28°), and after the treatment, clinker residue content of soil evaluated to 5% (WRC = 5%).


2013 ◽  
Vol 405-408 ◽  
pp. 304-309 ◽  
Author(s):  
Jing Cai ◽  
Yong Yu Wang ◽  
Ming Da Luo

To find the influence of the layout of punning position in dynamic compaction for loess, four model tests are performed, which equal in the tamping energy but differ in the layout of punning position. In model tests the settlement, the dry density and the shear strength parameters of the soil samples are measured and analysis of the effects of different test plans is made. The test results manifested that the decrease of the distance between the pounding points might result in an increment of the settlement, the dry density and the cohesive strength but not the angle of internal friction. And from the comparison of the test results, a more efficient layout of punning position is given.


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