Rockfall impacts on sand cushions with different soil mechanical characteristics using discrete element method

Naito, Naoto; Maeda, Kenichi; Konno, Hisashi; Ushiwatari, Yuji; Suzuki, Koichi; Kawase, Ryoji

doi:10.1016/j.sandf.2020.02.008

Cited by 32 publications

(18 citation statements)

References 7 publications

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“…However, it was unpractical to simulate the sand cushion with the particle size of 0.1 mm, especially in the actual engineering scale. Naito et al [18] examined the effect of the particle size of the sand on the maximum impact force and defined K as the ratio of the diameter of the falling block to the maximum diameter of the sand particle. The results indicated that the larger particle size of the sand, the lower the impact force.…”

Section: The Dem Methodsmentioning

confidence: 99%

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A Discrete Numerical Study of the Effect of the Thickness and the Porosity of the Sand Cushion on the Impact Response Due to the Rockfall

Yuan¹,

Zhao²,

Li³

et al. 2022

Computer Modeling in Engineering &Amp; Sciences

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The prevention and the reduction of the rockfall are the common measures of the prevention and the reduction of disasters. When the rock-shed resists the impact of the rockfall, the force that acts on the structure consists of the cushion dead load and the impact-induced load, of which the dynamic process of the propagation of the impactinduced load is complex. Therefore, we conducted a numerical study to investigate the impact of the rockfall. Considering the highly discrete characteristic of the sand, we developed a numerical model on the basis of the discrete element method (DEM). The numerical model, which simulation results were validated by the results of real-scale experiments, was used to investigate the dynamic response of the impact force of the rockfall and the transmission of the impact force under the different magnitude of the falling height and the different thickness of the sand cushion. The results of our study indicated that the cushion thickness had little effect on the impact of the rockfall, and the dense sand cushion generated higher impact force than did the loose sand cushion. Although the high thickness enhanced the buffer performance of the sand cushion, the additional force induced by the dead load of sand cushion was significant. Therefore, to determine the appropriate thickness of the sand cushion, we suggested designers consider the buffer performance and the dead load of the sand cushion. The analysis presented in this paper provided a practical estimation of the impact-induced force of the thick sand cushion.

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Section: The Dem Methodsmentioning

confidence: 99%

“…More aforementioned numerical methods incorporated the finite element method (FEM). Although the maximum impact force can be approximated by the FEM, it is difficult to simulate the second wave [18]. The FEM treats the sand as a continuous material.…”

Section: Introductionmentioning

confidence: 99%

A Discrete Numerical Study of the Effect of the Thickness and the Porosity of the Sand Cushion on the Impact Response Due to the Rockfall

Yuan¹,

Zhao²,

Li³

et al. 2022

Computer Modeling in Engineering &Amp; Sciences

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“…Shen et al (2019) investigated the mechanism of rockfall impact against a granular soil buffering layer above a concrete/rock shed by discrete element method, which indicates that the maximum impact force increases linearly with the rockfall sphericity. Naito et al (2020) used a discrete element method to investigate the cushioning performance of a sand cushion and proposed the effective and rational measures for the protection of the rock-shed.…”

Section: Introductionmentioning

confidence: 99%

A Dynamic Damage Model for the Rock-Shed Roof Under the Rockfall

liu

2021

Preprint

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The dynamic response of the rock-shed roof under the rockfall is a complicated mechanical process, which mainly includes the following three deformation stages, e.g. the elastic compression, plastic damage compression and elastic resilience stages of the rock-shed roof. However, the existing models based on Hertz elastic-perfectly plastic contact theory cannot perfectly reflect the above mechanical process. Therefore, on basis of the classical Hertz contact theory, the damage of the rock-shed roof induced by the rockfall is firstly introduced to consider its effect on the material elastic modulus, and then the revised Hertz contact theory considering the damage is proposed. Secondly, in view of the existing calculation method of the maximum rockfall impact force based on the theorem of impulse, a new calculation method is proposed by combining the revised Hertz contact theory. Thirdly, according to the dynamic mechanical response process of the rock-shed roof under the rockfall and in view of the revised Hertz contact theory, a dynamic damage model for the rock-shed roof under the rockfall is proposed, which can perfectly illustrate the variation law of the impact force with the deformation of the rock-shed roof during the rockfall. Finally, the proposed model is verified with other models for the maximum rockfall impact force. In all, the proposed model can perfectly describe the dynamic mechanical behavior of the rock-shed roof under the rockfall, which can be referred for the engineering design.

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“…Collision of particles and between particles and walls (or blocks) is encountered in various natural and industrial problems, such as granular flows, sand dunes, and impacts of rock fragments with protective barriers, 1–15 processes of powders and grains in pharmaceutical, chemical engineering, and polymer technology applications, 16–21 or applications in unconventional reservoir stimulation such as impacts of proppants with the walls of fractured rocks and particle plugging studies 22–25 . The problem of impact of solid objects has also been studied in the context of interaction of rock fragments originated by landslide with civil engineering structures (such as bridges) as these collisions may influence the stability of engineering systems 26 .…”

Section: Introductionmentioning

confidence: 99%

Laboratory and discrete‐based numerical investigation on the collision problem of impactor‐block systems with soft‐porous and hard‐crystalline analog rocks

Luo

Kasyap

et al. 2021

Num Anal Meth Geomechanics

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We investigated experimentally the normal coefficient of restitution (COR) of impactors colliding on the surfaces of two different blocks; a soft‐porous block composed of plaster (dry impacts) and a hard‐crystalline rock composed of granite (dry and wet impacts). The experiments were performed in a range of low‐impact velocities and various particle types were used including perfectly spherical smooth glass beads and ceramic balls, rough glass beads as well as natural rough sand grains. Image processing was carried out to quantify the formed contours of craters caused by the surface damage of the soft blocks due to the impact. The results indicated very low COR values on the plaster block compared with the granite block as the energy was dissipated by means of surface plastic deformations on the plaster, however the contour crater images showed that the collision mechanisms depended on the roughness of the impactor. The behavior of impactor‐fluid‐block systems was dependent on both surface roughness and global morphology of the impactors. Discrete‐based (DEM) numerical simulations were performed to provide further insights into the behavior of the impactor‐block systems subjected to collision using the COR values from the experiments as the micro‐scale parameters and data from the literature as the macro‐scale parameters for the model calibration. The numerical output was used to observe the development of compression and tension force chain networks and how these involved during and after impact on different base blocks.

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Rockfall impacts on sand cushions with different soil mechanical characteristics using discrete element method

Cited by 32 publications

References 7 publications

A Discrete Numerical Study of the Effect of the Thickness and the Porosity of the Sand Cushion on the Impact Response Due to the Rockfall

A Discrete Numerical Study of the Effect of the Thickness and the Porosity of the Sand Cushion on the Impact Response Due to the Rockfall

A Dynamic Damage Model for the Rock-Shed Roof Under the Rockfall

Laboratory and discrete‐based numerical investigation on the collision problem of impactor‐block systems with soft‐porous and hard‐crystalline analog rocks

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