Exploring the critical state properties and major principal stress rotation of sand in direct shear test using the distinct element method

2018 ◽  
Vol 20 (2) ◽  
Author(s):  
Mingjing Jiang ◽  
Jun Liu ◽  
Zhifu Shen ◽  
Banglu Xi
Keyword(s):  
Principal Stress ◽  
Critical State ◽  
Direct Shear Test ◽  
Shear Test ◽  
Distinct Element ◽  
Distinct Element Method ◽  
Direct Shear ◽  
Principal Stress Rotation ◽  
Stress Rotation ◽  
Major Principal Stress

DISTINCT ELEMENT METHOD SIMULATION ON DEFORMATION MODE AND STRESS STATE FOR SPECIMEN SHAPE IN DIRECT SHEAR TEST

2014 ◽  
Vol 11 (02) ◽  
pp. 1342004 ◽  
Author(s):  
BYEONG-SU KIM ◽  
SEONG-WAN PARK ◽  
SHOJI KATO
Keyword(s):  
Stress State ◽  
Plane Strain ◽  
Direct Shear Test ◽  
Shear Test ◽  
Distinct Element ◽  
Deformation Mode ◽  
Distinct Element Method ◽  
Strain Condition ◽  
Direct Shear ◽  
Specimen Shape

In order to examine the deformation mode and the stress state according to the specimen shape in the direct shear test (DST), a series of the three-dimensional DEM (distinct element method) simulations of the DST for sandy soils were carried out with the circular and the rectangular specimens. From the obtained results, the deformation mode of the rectangular specimen was under the plane strain condition, while the deformation mode of the circular specimen could not be explained as a plane strain condition. In addition, the principal stress states around the potential shear plane were analyzed and discussed by means of the analysis of the soil particle level.

scholarly journals Influence of principal stress direction on the stress-strain-strength behaviour of completely decomposed granite

2010 ◽  
Vol 8 (1) ◽  
pp. 79-97 ◽  
Author(s):  
Md. Kumruzzaman ◽  
Jian-Hua Yin
Keyword(s):  
Principal Stress ◽  
Hollow Cylinder ◽  
Principal Stress Rotation ◽  
Strength Parameters ◽  
Principal Stress Direction ◽  
Stress Rotation ◽  
Strength Behavior ◽  
Major Principal Stress ◽  
Decomposed Granite ◽  
Completely Decomposed Granite

The measurement and study of the stress-strain-strength behavior of soils in general stress states involving principal stress rotation are necessary and valuable. To investigate the strength behavior under principal stress rotation, a series of undrained tests on compacted hollow cylinder specimens of completely decomposed granite (CDG) was carried in hollow cylinder apparatus. Tests were conducted using constant inside and outside pressures and maintained a fixed angle of rotation of principal stress with the vertical (?). Seven different angles of major principal stress orientations were used to cover the entire range of major principal stress directions from vertical to the horizontal. Two different confining stresses were used to find out the variations of the experimental results. It is observed that the deviator stresses as well as excess pore pressures decrease with the angle ?. It is also observed that specimens were getting softer with the increase of ?. The results also show a significant influence of principal stress direction angle on the strength parameters. It is found that the angle ? is related to the occurrence of cross-anisotropy and the localization which resulted in a pronounced influence on the strength parameters of the CDG specimens.

scholarly journals Influence of Structural Plane Microscopic Parameters on Direct Shear Strength

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanhui Cheng ◽  
Weijun Yang ◽  
Dongliang He
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Direct Shear ◽  
Stiffness Ratio ◽  
Structural Plane

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.

Soil Shear Strength Characteristic in Slope Disintegration Area

2013 ◽  
Vol 353-356 ◽  
pp. 735-739
Author(s):  
Xiao Ming Zhang ◽  
Shu Wen Ding ◽  
Shuang Xi Li
Keyword(s):  
Shear Strength ◽  
Direct Shear Test ◽  
Shear Test ◽  
Clay Content ◽  
Scientific Basis ◽  
Soil Mechanic ◽  
Direct Shear ◽  
Soil Cohesion ◽  
Soil Shear Strength ◽  
The Relationship

Development of slope disintegration is close to soil mechanic characteristics such as shear strength indices. Soil grain diameter and water content were tested. Soil direct shear test was conducted to analyze the relationship between shear strength indices and the influencing factors. The experimental data indicate that clay content and the range affect soil cohesion value and the scope. Soil cohesion increases with bulk density before 1.6g/cm3. But it decreases when the bulk after that. The results could provide a scientific basis for control of slope disintegration.

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