Effects of confining pressure and loading path on deformation and strength of cohesive granular materials: a three-dimensional DEM analysis

Shao, Jian‐Fu; Liu, Zaobao; Shi, Chong; Saxcé, Géry de

doi:10.1007/s11440-018-0671-4

Cited by 31 publications

(14 citation statements)

References 37 publications

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“…The rigid servo refers to the synchronous deformation of the nodes on the boundary wall [18], while the flexible servo refers to the continuous adjustment of the nodes on the wall with loading [19], and the adjustment is controlled by the force of the shell structural unit. Due to the different action mechanisms of soft servo and rigid servo, it affects the macromechanical parameters reflected by the stress-strain curve obtained by the compression test.…”

Section: The Influence Of Soft and Rigid Servos On The Test Curvementioning

confidence: 99%

Numerical Simulation Study on Compression Characteristics of Gravelly Soil Mixture Based on Soft Servo Method

et al. 2021

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Because of complex mechanical properties and deformation mechanism, gravel soil mixture is an important medium of concern in the field of geotechnical engineering. Based on the continuous-discontinuous coupling algorithm formed by the structure shell elements and the particle discrete element method (PFC3D), the soft servo loading of the sample is realized, and the typical triaxial compression test data are used to calibrate mesoscale parameters. Furthermore, the numerical tests under different rock contents and confining pressure are carried out. The change rule of shear strength of mixed medium is discussed. It shows that the continuous-discontinuous coupling algorithm achieves a good effect in reflecting the deformation process. Under the mechanism of the flexible servo, the failure mode of the sample takes on drum-failure mode, and the internal of the damaged sample forms an obvious asymmetric X-shaped shear band. With the increase of stone content, the internal friction angle and cohesive force distribution of the sample have certain discreteness, but on the whole, the internal friction angle and cohesive force increase with the increase of stone content. The results can provide a reference for the parameter determination of mixed mediums such as gravel soil.

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Section: The Influence Of Soft and Rigid Servos On The Test Curvementioning

confidence: 99%

Numerical Simulation Study on Compression Characteristics of Gravelly Soil Mixture Based on Soft Servo Method

et al. 2021

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“…The outstanding advantage of DEM is the ability to explicitly handle the discrete/heterogeneous nature of granular materials by modelling particle-scale properties, including size and shape which play an important role in strain localization. DEM may be used to frictional [29,30,39,66] and frictional-cohesive materials [32,38,72]. The disadvantages are related to an enormous computational cost and an extensive calibration based on experimentally measured macro-scale properties.…”

Section: D Dem Modelmentioning

confidence: 99%

3D DEM simulations of monotonic interface behaviour between cohesionless sand and rigid wall of different roughness

2020

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The paper deals with three-dimensional simulations of a monotonic quasi-static interface behaviour between cohesionless sand and a rigid wall of different roughness during wall friction tests in a parallelly guided direct shear test under constant normal stress. Numerical modelling was carried out by the discrete element method (DEM) using spheres with contact moments to approximately capture a non-uniform particle shape. The varying wall surface topography was simulated by a regular mesh of triangular grooves (asperities) along the wall with a different height, distance and inclination. The calculations were carried out with different initial void ratios of sand and vertical normal stress. The focus was to quantify the effect of wall roughness on the evolution of mobilized wall friction and shear localization, also to specify the ratios between slip and rotation and between shear stress/force and couple stress/moment in the sand at the wall. DEM simulations were generally in good agreement with reported experimental results for similar interface roughness. The findings presented in this paper offer a new perspective on the understanding of the wall friction phenomenon in granular bodies.

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“…When the local contact force reaches its critical values, the contact interface occurs breakage according to its failure criterion, such as in Figure 2. In order to describe the failure process, a unified failure criterion for both bond contact and smooth joint contact has been proposed in our previous study [50]. This criterion is still adopted in the present study.…”

Section: Description Of Mechanical Behavior Of Differentmentioning

confidence: 99%

“…After that, the calibration of microparameter of bond contact model is mainly based on the experimental data reported in [22] by taking an iterative approach. The detailed identification process can be referred in our previ-ous study [50], while for the parameters of smooth joint contact model, a similar iterative process is also adopted in direct shear test and tensile test. During this process, a uniform nonlinear failure criterion proposed in our another study [4] is introduced in two models.…”

Section: Determination Of Micromechanical Parametersmentioning

confidence: 99%

Study of Interactions between Induced and Natural Fracture Effects on Hydraulic Fracture Propagation Using a Discrete Approach

et al. 2021

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The interaction mode of induced fracture and natural fracture plays an important role in prediction of hydraulic fracture propagation. In this paper, a two-dimensional hydromechanical coupled discrete element model is first introduced in the framework of particle flow simulation, which can well take into account mechanical and hydraulic properties of rock samples with natural fracture. The model’s parameters are strictly calibrated by conducting numerical simulations of uniaxial compression test and direct tensile and shear tests, as well as fluid flow test. The effectiveness of coupled model is also assessed by describing hydraulic fracture propagation in two representative cases, respectively, rock samples with and without preexisting fracture. With this model in hand, the effects of interaction between induced and natural fractures with different approach angles and differential stresses on fluid injection pressure and fracture propagation patterns are investigated and discussed. Results suggest that the interaction modes mainly involve three basic behaviors including the arrested, captured with offset, and directly crossing. For a given differential stress, the captured offset of hydraulic fracture by natural fracture gradually decreases with the approach angle increase, while for a fixed approach angle, that captured offset increases with differential stress decrease.

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Effects of confining pressure and loading path on deformation and strength of cohesive granular materials: a three-dimensional DEM analysis

Cited by 31 publications

References 37 publications

Numerical Simulation Study on Compression Characteristics of Gravelly Soil Mixture Based on Soft Servo Method

Numerical Simulation Study on Compression Characteristics of Gravelly Soil Mixture Based on Soft Servo Method

3D DEM simulations of monotonic interface behaviour between cohesionless sand and rigid wall of different roughness

Study of Interactions between Induced and Natural Fracture Effects on Hydraulic Fracture Propagation Using a Discrete Approach

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