Study on a determination manner of discrete element method parameters in a bonded granular material

Kikkawa, Naotaka; Hori, Tomohito; Itoh, Kazuya; Mitachi, Toshiyuki

doi:10.3208/jgs.8.221

Cited by 5 publications

(3 citation statements)

References 22 publications

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“…In this study, an unconfined compression test apparatus 7 ) was used as the test apparatus for the simple bending test. The unconfined compression test apparatus is commonly used for concrete, soft-rock and clay.…”

Section: Experiments and Simulationmentioning

confidence: 99%

“…These values were slightly higher than the unconfined compression strength (46.2 N/mm 2 ) and the elastic (ultrasonic) wave propagation velocities (V p_bm = 3,920 and V s_bm = 2,340 m/sec) of the cement milk specimen used for the miniature segments. These values, however, had not much influence on the DEM parameters, such as the stiffness of the sphere elements, and the parallel-bonds that were determined using the determination manner, a procedure adopted and discussed in previous studies 7 , 8 ) .…”

Section: Experiments and Simulationmentioning

confidence: 99%

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Unstable behavior of segmental ring under various pressures and its discrete element simulation

et al. 2019

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In February 2012, a serious accident which resulted in five fatalities happened during a TBM-tunnel construction under the seabed in Japan. The cause of the accident appeared to be due to the Key-segment slipping out of the segment ring by the thrusting tailskin (wire brushes) of the TBM into the segment ring. This resulted in the collapse of the rings, causing the seabed ground and seawater to flow into the tunnel. We investigated how thin and thick segments without any circumferential joints behave under isotropic and anisotropic pressures using small-scale physical model. In the model tests, pressures were applied to the surroundings of the segment rings and the strains at each segment were measured in order to evaluate the damage. In addition, cases where lubrication on the contact area between the K- and B-segments was present or not were investigated and their discrete element simulations were also conducted.

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Section: Experiments and Simulationmentioning

confidence: 99%

Section: Experiments and Simulationmentioning

confidence: 99%

Unstable behavior of segmental ring under various pressures and its discrete element simulation

et al. 2019

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“…8) Kikkawa et al proposed a systematic procedure for determining the input parameters of the DEM using the results of parametric studies. 9) The used parameter values in such past studies were based on the researchers' subjective judgment. There are four parameters in the Voigt contact model in ROCKY DEM, which is the commercial DEM software that is used in this study, and they are Young's modulus, Poisson's ratio, the restitution coefficient, and the friction coefficient.…”

Section: Introductionmentioning

confidence: 99%

Genetic Algorithm Based Automatic Input Parameter Calibration Method for the Discrete Element Modeling of Vibration Feeders

et al. 2021

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Using the genetic algorithm, this paper developed an automatic method for calibrating the used four input parameters (Young's modulus, Poisson's ratio, coefficient of restitution, and friction coefficient) in the discrete element modeling (DEM) of vibration feeders. Two objective functions were used: (1) the difference in the results between the DEM simulation and the experiment and (2) the computation time of the DEM simulation. We conducted preliminary experiments to obtain an average experimental response of the vibration feeding and found that single-item-clogging usually arises near the feeder tray outlet. The proposed method managed to find the required set of parameters for minimizing the two objective functions by multi-objective optimization using the genetic algorithm. Overall, we confirmed that the obtained parameter values were physically reasonable in comparison with those of previous studies.

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Study on Mechanism of Rock Fall at Tunnel Cutting Face After Blasting

Sato¹,

Kikkawa²,

Hiraoka³

et al. 2017

Proceedings of International Structural Engineering and Construction

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There are around 10 casualties due to rock-fall at cutting face annually in conventional tunnel construction in Japan. As from the analysis conducted on the cases involving such casualties, workers were either killed or seriously injured when they works in front of or near the cutting face. For the purpose of evaluating the mechanism of rock fall at tunnel cutting face, this paper performed experimental tests which involved blasting to excavate a model ground of tunnel cutting face, and then analyzed the stress state which is in the cutting face by using Discrete Element Method (DEM) simulation. Based on the results, the tensile stresses remained even when the action of gas expansion due to blasting has completed. Therefore, it is suggested that rock falls might be induced because of the residual tensile stresses. The tensile stresses would gradually open small cracks between rocks and then rocks may suddenly fall after sufficient crack opening due to gravity.

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Study on a determination manner of discrete element method parameters in a bonded granular material

Cited by 5 publications

References 22 publications

Unstable behavior of segmental ring under various pressures and its discrete element simulation

Unstable behavior of segmental ring under various pressures and its discrete element simulation

Genetic Algorithm Based Automatic Input Parameter Calibration Method for the Discrete Element Modeling of Vibration Feeders

Study on Mechanism of Rock Fall at Tunnel Cutting Face After Blasting

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