Macro- and micromechanical evaluation of cyclic simple shear test by discrete element method

Asadzadeh, Mozhgan; Soroush, Abbas

doi:10.1016/j.partic.2016.05.015

Cited by 18 publications

(2 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, these experimental studies have no access to the micro-mechanism underlying the soil responses. Discrete element modelling of cyclic tests were also widely adopted to link the macroscale soil responses and underlying micro-mechanism during cyclic loading including [20][21][22]. However, these studies were limited to symetric two-way loadings, which are different from the real loading scenarios in offshore wind farms as found by Jalbi et al [15].…”

Section: Background and Motivationmentioning

confidence: 99%

Macro- and micro-mechanics of granular soil in asymmetric cyclic loadings encountered by offshore wind turbine foundations

et al. 2019

View full text Add to dashboard Cite

Offshore wind turbine foundations are subject to 10 7-10 8 cycles of loadings in their designed service life. Recent research shows that under cyclic loading, most soils change their properties. Discrete Element Modelling of cyclic simple shear tests was performed using PFC2D to analyse the micromechanics underlying the cyclic behaviours of soils. The DEM simulation were first compared with previous experimental results. Then asymmetric one-way and two-way cyclic loading pattern attained from real offshore wind farms were considered in the detailed parametric study. The simulation results show that the shear modulus increases rapidly in the initial loading cycles and then the rate of increase diminishes; the rate of increase depends on the strain amplitude, initial relative density and vertical stress. It shows that the change of soil behaviour is strongly related to the variation of coordination number, rotation of principal stress direction and evolution of degree of fabric anisotropy. Loading asymmetry only affects soil behaviours in the first few hundred of cycles. In the long term, the magnitude of (γ max − γ min) rather than loading asymmetry dominates the soil responses. Cyclic loading history may change the stress-strain behaviour of a soil to an extent dependent on its initial relative density. Keywords Discrete element modelling • Cyclic loading • Soil stiffness • Micro-mechanism Abbreviations a Parameter defining the magnitude of fabric anisotropy a max Fabric anisotropy at maximum shear strain a min Fabric anisotropy at minimum shear strain d 50 Diameter at which 50% of the sample's mass is comprised of particles with a diameter less than this value e Void ratio G Shear modulus M max Maximum moments in a load cycle M min Minimum moments in a load cycle and M ult Ultimate moment capacity N c Coordination number t Deviator stress s′ Mean stress γ max Maximum shear strain (shear strain amplitude) of a cyclic simple shear test γ min Minimum shear strain in a cyclic simple shear test ζ c Ratio of minimum moment to the maximum moment η c Parameter defined to quantify the degree of asymmetry of cyclic loading θ a Direction of the principal fabric σ Vertical stresses on the sample in a cyclic simple shear test τ max Shear stress at maximum shear strain τ min Shear stress at minimum shear strain * Liang Cui

show abstract

Section: Background and Motivationmentioning

confidence: 99%

Macro- and micro-mechanics of granular soil in asymmetric cyclic loadings encountered by offshore wind turbine foundations

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The stress-strain variation is fundamental for analyzing soil reciprocating shear characteristics. Asadzadeh et al [21] found that with reciprocating shears, the uneven distribution of volumetric strain within coarse-grained soils was an important cause of local dilatancy and contraction behaviors. Saberi et al [22] stated that soil stress hardening and stress softening were caused by the mechanical interaction between soil grains under reciprocating shear.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Reciprocating Shear Characteristics and Strength Deterioration of Argillaceous Siltstone Rockfill Materials

Xiong

Shen

et al. 2023

Applied Sciences

View full text Add to dashboard Cite

The reciprocating shear mechanical properties and strength deterioration mechanisms of rockfill materials are of great research significance for high-fill slope stability analysis. To study the shear strength characteristics of argillaceous siltstone rockfill materials with different fabric characteristics under reciprocating shear loading, we analyzed the shear strength, hysteresis loop area, damping ratio, shear strength parameter, and shear stiffness of coarse-grained soils with different coarse grain contents using a coarse-grained soil direct shear testing machine capable of reciprocating shear and revealed their strength deterioration mechanism. The test results show that the shear strength of argillaceous siltstone rockfill materials is significantly affected by the coarse grain content and the number of reciprocating shears. Specifically, the shear strength increases with the coarse grain content and decreases with the number of reciprocating shears. The hysteresis loop area is positively correlated with the coarse grain content and negatively correlated with the number of reciprocating shears. The damping ratio is not related to the coarse grain content but tends to decrease with the number of reciprocating shears. Soil cohesion and the internal friction angle increase with the coarse grain content and decrease with the number of reciprocating shears. The soil failure shear stiffness is linearly correlated with the coarse grain content, and the normalized shear stiffness is logarithmically related to the number of reciprocating shears. According to these relationships, an empirical formula for the shear stiffness of argillaceous siltstone rockfill materials under different coarse grain contents and different numbers of reciprocating shears can be established to provide a basis for analyzing rockfill stability.

show abstract

Evaluation of stress and strain non-uniformity during cyclic simple shear test using DEM: effect of the horizontal platen asperities

Asadzadeh

Soroush

2018

Granular Matter

View full text Add to dashboard Cite

Macro- and micromechanical evaluation of cyclic simple shear test by discrete element method

Cited by 18 publications

References 25 publications

Macro- and micro-mechanics of granular soil in asymmetric cyclic loadings encountered by offshore wind turbine foundations

Macro- and micro-mechanics of granular soil in asymmetric cyclic loadings encountered by offshore wind turbine foundations

Experimental Study on the Reciprocating Shear Characteristics and Strength Deterioration of Argillaceous Siltstone Rockfill Materials

Evaluation of stress and strain non-uniformity during cyclic simple shear test using DEM: effect of the horizontal platen asperities

Contact Info

Product

Resources

About