Evaluation the Shear Strength Behavior of aged MSW using Large Scale In Situ Direct Shear Test, a case of Tabriz Landfill

2020 ◽  
Vol 18 (7) ◽  
pp. 717-733 ◽  
Author(s):  
Mohsen Keramati ◽  
Masoud Shahedifar ◽  
Mohammad Hosein Aminfar ◽  
Hasan Alagipuor
Keyword(s):  
Shear Strength ◽  
Large Scale ◽  
Direct Shear Test ◽  
Shear Test ◽  
Direct Shear ◽  
Strength Behavior

scholarly journals Influence of Maximum Particle Diameter on the Mechanical Behavior of Soil-Rock Mixtures

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhuoling He ◽  
Junyun Zhang ◽  
Tao Sun
Keyword(s):  
Shear Strength ◽  
Large Scale ◽  
Direct Shear Test ◽  
Shear Test ◽  
Particle Diameter ◽  
Size Difference ◽  
Direct Shear ◽  
Fine Grained ◽  
Fine Grained Soil ◽  
Maximum Particle

With the steady development of the development of the western region in China, the construction of mountain highways has developed rapidly, and the soil-rock mixed filler, as an excellent filler, is widely used in the subgrade filling of mountain highways. Unlike ordinary fine-grained soil, the source of the soil-rock mixtures (S-RMs) is not unique, and the particle size difference is large and the water content is not uniform, resulting in very complicated mechanical properties. But the current highway embankment codes are still mainly established on the fine-grained soil. It is not fully applicable to soil-rock filled embankment. Based on soil-rock filled embankment engineering practice, this research uses a large-scale direct shear test to research the mechanical characteristics of the S-RMs with different maximum particle diameters. According to the large-scale direct shear test of S-RMs with different maximum particle diameters, the shear displacement vs shear stress curve, shear dilation, and strength characteristics with maximum particle diameter were analyzed. Results demonstrate that whether secondary hardening occurs mainly depends on the normal stress and the maximum particle diameter of the filler. At different maximum particle diameters, the horizontal displacement vs vertical displacement curves of the S-RMs can be roughly divided into continuous shearing and beginning of shearing and quick dilation. And the shear strength increases with the increase of the maximum particle diameter. Moreover, the cohesion decreases first and then increases with the increase of the maximum particle diameter, and the internal friction angle increases with the increase of the maximum particle diameter. Therefore, some RBs with large particle diameter added to filler can effectively improve the shear strength of the S-RMs, which may be valuable for realistic engineering.

scholarly journals Determining the Shear Strength Properties of a Soil-geogrid Interface Using a Large-scale Direct Shear Test Apparatus

2020 ◽  
Author(s):  
Jakub Stacho ◽  
Monika Sulovska ◽  
Ivan Slavik
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Large Scale ◽  
Direct Shear Test ◽  
Shear Test ◽  
Strength Properties ◽  
Coarse Grained ◽  
Direct Shear ◽  
Test Apparatus ◽  
Fine Gravel

The paper deals with the laboratory testing of coarse-grained soils that are reinforced using a geogrid. The shear strength properties were determined using a large-scale direct shear test apparatus. The tests were executed on original as well as on reinforced soil, when the geogrid was placed on a sliding surface, which permitted determining the shear strength properties of the soil-geogrid interface. The aim of the tests was to determine the interface shear strength coefficient α, which represents the ratio of the shear strength of the soil-geogrid interface to the unreinforced soil. The tests were executed on 3 samples of coarse-grained materials, i.e., poorly graded sand, poorly graded fine gravel and poorly graded medium gravel. Two types of geogrids were tested, i.e., a woven polyester geogrid and a stiff polypropylene geogrid. The results of the laboratory tests on the medium gravel showed that the reduction coefficient α reached higher values in the case of the stiff polypropylene geogrid. In the cases of the fine gravel and sand, the values of the interface coefficient α were similar to each other. The shear strength of the interface was reduced or was similar to the shear strength of unreinforced soil in a peak shear stress state, but significantly increased with horizontal deformations, especially for the fine gravel and sand. The largest value of the coefficient α was measured in the critical shear stress state. Based on the results of the testing, a correlation which allows for determining the optimal grain size distribution was obtained.

scholarly journals Effect of Rock Particle Content on the Mechanical Behavior of a Soil-Rock Mixture (SRM) via Large-Scale Direct Shear Test

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Longqi Liu ◽  
Xuesong Mao ◽  
Yajun Xiao ◽  
Qian Wu ◽  
Ke Tang ◽  
...  
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Large Scale ◽  
Direct Shear Test ◽  
Shear Test ◽  
Volumetric Strain ◽  
Direct Shear ◽  
Stress Strain ◽  
Particle Content ◽  
Rock Particle

The mechanical strength of the landslide deposits directly affects the safety and operation of the roads in the western mountainous area of China. Therefore, the research is aimed at studying the mechanisms of a landslide deposit sample with different rock particle contents by analyzing its characteristics of the stress-strain behavior, the “jumping” phenomenon, the volumetric strain, and the shear strength parameters via a large-scale direct shear test. Stress-strain results show that stress-strain curves can be divided into 3 different stages: liner elastic stage, yielding stage, and strain-hardening stage. The shear strength of SRM behaves more like “soil” at a lower rock particle content and behaves more like “rock joints” at a higher rock particle content. Characteristics of the “jumping” phenomenon results show that the “intense jumping” stage becomes obvious with the increasing rock particle content and the normal stress. However, the lower the rock particle content is, the more obvious the “jumping” phenomenon under the same normal stress is. Volumetric strain results show that the sample with a lower rock particle content showed a dilatancy behavior under the low normal stress and shrinkage behavior under the high normal stress. The dilatancy value becomes smaller with the increasing normal stress. The maximum shear stress value of the rock particle content corresponds to the maximum value of dilatancy or shrinkage. We also conclude that the intercept of the Mohr failure envelope of the soil-rock mixture should be called the “equivalent cohesion,” not simply called the “cohesion.” The higher the normal stress and rock particle content are, the bigger the equivalent cohesion and the internal friction angle is.

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.

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

In-situ direct shear test and numerical simulation of slate structural planes with thick muddy interlayer along bedding slope

2021 ◽  
Vol 143 ◽  
pp. 104791
Author(s):  
Xin Tan ◽  
Ya-kun Ren ◽  
Teng-long Li ◽  
Su-hua Zhou ◽  
Jiu-chang Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Direct Shear Test ◽  
Shear Test ◽  
Direct Shear ◽  
Bedding Slope
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