Skin Friction Directionality in Monotonically- and Cyclically-Loaded Bio-inspired Piles in Sand

Martínez, Alejandro

doi:10.37308/dfijnl.20200831.222

Cited by 10 publications

(2 citation statements)

References 36 publications

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“…During the pullout and installation in sands, bio-inspired piles exhibited that the shaft capacity varies depending on the direction of load transfer 19 . The bio-inspired piles exhibited greater skin friction when subjected to tensile pullout compared to when they were jacked 20 . The bioinspired pile pulled out in the cranial direction produces less vertical displacement and higher skin friction resistance than the caudal direction with smooth surface pile 18 .…”

Section: Introductionmentioning

confidence: 99%

Interface Frictional Anisotropy of Dilative Sand

Nawaz,

Lee,

Chong

et al. 2023

Preprint

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Understanding direction-dependent friction anisotropy is necessary to optimize interface shear resistance across soil-structure. Previous studies estimated interface frictional anisotropy quantitatively using contractive sands. However, no studies have explored how sand with a high dilative tendency around the structural surface affects the interface shear response. In this study, a series of interface direct shear tests are conducted with selected French standard sand and snakeskin-inspired surfaces under three vertical stresses (50, 100, and 200 kPa) and two shearing directions (cranial → caudal or caudal → cranial). First, the sand-sand test observes a higher dilative response, and a significant difference between the peak and residual friction angles (ϕpeak - ϕres = 8°) is obtained at even a lower initial relative density Dr = 40%. In addition, the interface test results show that (1) shearing against the scales (cranial shearing) mobilizes a larger shear resistance and produces a dilative response than shearing along the scales (caudal shearing), (2) a higher scale height or shorter scale length exhibits a higher dilative tendency and produces a higher interface friction angle, and (3) the interface anisotropy response is more pronounced during cranial shearing in all cases. Further analysis reveals that the interface friction angle and dilation angle are decreased with the scale geometry ratio, and the first shearing effect is diminished during the second shearing response.

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Section: Introductionmentioning

confidence: 99%

Interface Frictional Anisotropy of Dilative Sand

Nawaz,

Lee,

Chong

et al. 2023

Preprint

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“…These surfaces have the potential to lead to new design opportunities for the installation and performance of geotechnical engineering structures. For instance, O'Hara and Martinez [25] provide and Martinez and O'Hara [20] data from centrifuge pile load tests indicating that the skin friction of a pile with an asymmetric surface is significantly higher during tensile pullout than during jacking installation.…”

Section: Introductionmentioning

confidence: 99%

Directionally dependent strength and dilatancy behavior of soil–structure interfaces

Stutz

Martínez

2021

Acta Geotech.

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Soil-structure interfaces typically exhibit a shear behavior that is independent of the direction of relative displacement due to symmetry in the solid material's surface profile. This experimental study investigates the interface shear behavior of surfaces with asymmetric profiles inspired by the scales of snake skin. The results of shear box interface tests on two sandy soils indicate that the peak and residual interface shear strengths and dilatancy are greater when the soil is displaced against the sharp edges of the asperities (cranial direction) than when the soil is displaced along the asperities (caudal direction). The experimental results indicate that the effect of asperity geometry on the interface shear response can be captured with the ratio of asperity length to asperity height (L/H). Analysis of the stress-dilatancy behavior indicates that interfaces with a relatively short asperity length follow a classical flow rule developed for soils. However, the relationship between the mobilized stress ratio and the dilatancy rate is shown to be a function of the shearing direction and asperity geometry. Implementation of snake skin-inspired profiles on the surface of geotechnical structures may provide benefits in performance and efficiency during installation and service life. In general, the results of this study indicate the behavior of the soil-structure interfaces sheared in the cranial direction is similar to that of interfaces between soil and fully rough surfaces. In contrast, the behavior of the soil-structure interface sheared in the caudal direction shares characteristics with that of interfaces with smooth surfaces, including the mobilization of smaller a interface strength and dilation.

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Biological perspectives in geotechnics: theoretical developments

Jain,

Mishra,

Tiwari

et al. 2023

Rev Environ Sci Biotechnol

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The interaction of bio–geosphere dates to the formation of first unicellular microbes on earth. However, it is only relatively recently that the complex biological interactions are observed, characterised, and simulated for its use in the domain of geotechnical engineering. Also, many bioinspired approaches have been utilised in computational geotechnics for optimisation and data analysis process. The living phase present in the soil system hold a bearing on the majority of geochemical reactions and assist in modifying its fundamental and engineering behaviour. It necessitates revaluation and rescrutinisation of the conventional theories and formulations in geotechnical engineering, where soil has always been considered as an inert engineering material from biological perspective. To that end, this manuscript provides a critical review on biological approaches used in geotechnical engineering by highlighting the ongoing developments, achievements, and challenges to implement the processes. The review further emphasises the role of biological systems on the alteration of fundamental properties of soils and their consequences on effective stress, strength and stiffness, volume change and conduction properties of soils. Overall, the manuscript provides a basic understanding on the biological intervention in the soil system and the importance of consideration of the fourth phase in the soil system, i.e., the living phase, while describing such interventions.

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Skin Friction Directionality in Monotonically- and Cyclically-Loaded Bio-inspired Piles in Sand

Cited by 10 publications

References 36 publications

Interface Frictional Anisotropy of Dilative Sand

Interface Frictional Anisotropy of Dilative Sand

Directionally dependent strength and dilatancy behavior of soil–structure interfaces

Biological perspectives in geotechnics: theoretical developments

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