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Abstract Soil penetration is an energy-intensive process that is common in both nature and civil infrastructure applications. Many human construction activities involve soil penetration that is typically accomplished through impact-driving, pushing against a reaction mass, excavating, or vibrating using large equipment. This paper presents a numerical investigation into the self-penetration process of a probe that uses an ‘anchor–tip’ burrowing strategy with the goal of extending the mechanics-based understanding of burrower–soil interactions at the physical dimensions and stress levels relevant for civil infrastructure applications. Self-penetration is defined here as the ability of a probe to generate enough anchorage forces to overcome the soil penetration resistance and advance the probe tip to greater depths. 3D Discrete element modeling simulations are employed to understand the self-penetration process of an idealized probe in noncohesive soil along with the interactions between the probe’s anchor and tip. The results indicate that self-penetration conditions improve with simulated soil depth, and favorable probe configurations for self-penetration include shorter anchor–tip distances, anchors with greater length and expansion magnitudes, and anchors with a greater friction coefficient. The results shed light on the scaling of burrowing forces across a range of soil depths relevant to civil infrastructure applications and provide design guidance for future self-penetrating probes.
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A numerical study on the multi-cycle self-burrowing of a dual-anchor probe in shallow coarse-grained soils of varying density
Abstract Development of self-burrowing probes that can penetrate soils without the aid of external reaction force from drill rigs and trucks would facilitate site characterization activities and deployment of sensors underneath existing structures and in locations with limited access (e.g., toe of dams, extraterrestrial bodies). Successful deployment of self-burrowing probes in the field will require several cycles of expansion, penetration, and contraction motions due to the geometric constraints and the increase in soil strength with depth. This study explores the multi-cycle performance of a dual-anchor self-burrowing probe in granular assemblies of varying density using discrete element modeling simulations. The simulated probe consists of an expandable top shaft, expandable bottom shaft, and a conical tip. The expansion of the shafts are force-controlled, the shaft contraction and tip advancement are displacement-controlled, and the horizontal tip oscillation is employed to reduce the penetration resistance. The performance of the self-burrowing probe in terms of self-burrowing distance is greater in the medium dense specimen than in the dense and loose specimens due to the high magnitude of anchorage force in comparison with penetration resistance. For all three soil densities, most of the mechanical work is done by tip oscillation; however, this accounts for a greater percentage of the total work in the denser specimen. Additionally, while tip oscillation aids in enabling self-burrowing to greater depths, it also produces a greater work demand. The results presented here can help evaluate the effects of soil density on probe prototypes and estimate the work requited for self-burrowing.
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- Award ID(s):
- 1942369
- PAR ID:
- 10469864
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Acta Geotechnica
- Volume:
- 19
- Issue:
- 3
- ISSN:
- 1861-1125
- Format(s):
- Medium: X Size: p. 1231-1250
- Size(s):
- p. 1231-1250
- Sponsoring Org:
- National Science Foundation
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