Effect of particle shape on the development of 2D soil arching

Chen, Ren Peng; Liu, Qi Wei; Wu, Huai-Na; Wang, Hanlin; Meng, Fanbo

doi:10.1016/j.compgeo.2020.103662

Cited by 50 publications

(23 citation statements)

References 58 publications

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“…Nonetheless, we are more interested in capturing the general behavior of forces in our sample-such as the dependence of force chain morphology on the growth of the tunnel. This emergent behavior is more dependent on the distribution of particle shapes and boundary conditions than on the specific contact locations (22,32). In this regard, LS-DEM has shown high efficacy (33).…”

Section: Resultsmentioning

confidence: 99%

“…We use this mapping to explore patterns relating tunnel construction to force distributions in real time, in addition to other critical granular material attributes. Because the shape, position, and orientation of grains are crucial for determining force distributions in a soil (22)(23)(24)(25), we consider grain-scale properties of the excavated soil and their evolution in time. With XRCT, we achieve submillimeter-resolution 3D imaging on a frustum-shaped container of ants and soil during tunnel excavation.…”

Section: Significancementioning

confidence: 99%

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Unearthing real-time 3D ant tunneling mechanics

Macedo

Andò

Joy

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Granular excavation is the removal of solid, discrete particles from a structure composed of these objects. Efficiently predicting the stability of an excavation during particle removal is an unsolved and highly nonlinear problem, as the movement of each grain is coupled to its neighbors. Despite this, insects such as ants have evolved to be astonishingly proficient excavators, successfully removing grains such that their tunnels are stable. Currently, it is unclear how ants use their limited information about the environment to construct lasting tunnels. We attempt to unearth the ants’ tunneling algorithm by taking three-dimensional (3D) X-ray computed tomographic imaging (XRCT), in real time, of Pogonomyrmex ant tunnel construction. By capturing the location and shape of each grain in the domain, we characterize the relationship between particle properties and ant decision-making within an accurate, virtual recreation of the experiment. We discover that intergranular forces decrease significantly around ant tunnels due to arches forming within the soil. Due to this force relaxation, any grain the ants pick from the tunnel surface will likely be under low stress. Thus, ants avoid removing grains compressed under high forces without needing to be aware of the force network in the surrounding material. Even more, such arches shield tunnels from high forces, providing tunnel robustness. Finally, we observe that ants tend to dig piecewise linearly downward. These results are a step toward understanding granular tunnel stability in heterogeneous 3D systems. We expect that such findings may be leveraged for robotic excavation.

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Section: Resultsmentioning

confidence: 99%

Section: Significancementioning

confidence: 99%

Unearthing real-time 3D ant tunneling mechanics

Macedo

Andò

Joy

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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“…When the vertical displacement of the soil on the trap wall and the soil on the pile is the same, an equal settlement is formed, and the soil above this height sinks simultaneously. According to Chen et al [35], the vertical displacement of a layer (∆U) in equal settlement patterns is less than (s-a)/500 (i.e., 0.45 mm in Test 11). The maximum value of the average height of each section in this layer is the critical height H cr .…”

Section: Equal Settlementmentioning

confidence: 95%

“…According to Chen et al [35], the vertical displacement of a layer (ΔU) in equal settlement patterns is less than (s-a)/500 (i.e., 0.45 mm in Test 11). The maximum value of the average height of each section in this layer is the critical height Hcr.…”

Section: Equal Settlementmentioning

confidence: 95%

“…The Discrete Element Method (DEM) has been recently applied to simulate the soil arching in piled embankments [15,25,[33][34][35], which showed that DEM simulations can closely characterize the qualitative features of soil arching in piled embankments [35]. However, most of these DEM simulations still attempt to identify the soil arching according to the deformation pattern of the embankment, rather than the redistributions of the stress or contact force chains [15].…”

Section: Introductionmentioning

confidence: 99%

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Soil Arching of Piled Embankment in Equal Settlement Pattern: A Discrete Element Analysis

et al. 2021

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Soil arching, which occurs in the piled embankments, plays an important role in stress redistribution between the relatively soft subsoil and the stiffer piles. The formation of the soil arching depends on the differential settlement of the embankment fill above the pile and the subsoil. The soil arching effect is barely investigated in the literature from the perspective of differential settlement of piles and soils. Based on the discrete element method (DEM), this paper develops a classic trapdoor test model to investigate the differential settlement in piled embankment during the downward movement of the trapdoor, and to explore the formation mechanism of soil arching in equal settlement pattern by changing the width of the pile cap and the height of the embankment. Due to symmetry, only one section of the laboratory test model is simulated herein. It was found that the soil arching formed under the equal settlement pattern remained unchanged after a certain degree of development, and the height of the equal settlement did not change at 0.7(s-a), where s is the pile spacing, and a is the width of the pile cap. The height of the embankment (H) and the width of the pile cap (a) have a significant influence on the formation of the equal settlement pattern when the width of the trapdoor is kept constant. Both the decrease in “H” and the increase in “a” facilitate the differential settlement of the soil between the piles and the pile-soil, enabling the slip surface to develop upward gradually, thereby hindering the formation of the equal settlement pattern.

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Effects of particle morphology on the shear response of granular soils by discrete element method and 3D printing technology

Lei

Kang

2022

Num Anal Meth Geomechanics

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The development of quantitative correlation between particle morphology and shear responses of granular soils is an ongoing challenge. Herein, 3D printing technology, combined with the experiments and discrete element simulations were conducted to study the effects of different particle shapes on the particle migration, the development of shear zone, and the anisotropy of particle contact during shearing. Both numerical simulations and experimental tests confirmed that the increase of modified shape parameter Sh strengthens the interlock between particles, which in turn limits the shear deformation in the direction of shearing. As the shear load increases further, the rotation of particles begins to develop from both sides of the shear box boundary, which gradually expands to the center, and finally forms a stable disturbance region in the center of the specimen; meanwhile, the positions of the maximum particle rotation appear at the center and boundary of the shear zone. Moreover, particle shape does not affect the distribution of fabric anisotropy before loading, however, the change of particle shape parameter Sh makes the fabric anisotropy become prominent. In addition, particle shape is found to improve the shear resistance by changing the number and distribution of contacts between particles, rather than the contact force among particles.

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Effect of particle shape on the development of 2D soil arching

Cited by 50 publications

References 58 publications

Unearthing real-time 3D ant tunneling mechanics

Unearthing real-time 3D ant tunneling mechanics

Soil Arching of Piled Embankment in Equal Settlement Pattern: A Discrete Element Analysis

Effects of particle morphology on the shear response of granular soils by discrete element method and 3D printing technology

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