Vibro-Injection Pile Installation in Sand: Part I—Interpretation as Multi-material Flow

The installation of vibro-injection piles into saturated sand has a significant impact on the surrounding soil and neighboring buildings. It is generally characterized by a multi-material flow with large material deformations, non-stationary and new material interfaces, and by the interaction of the grain skeleton and the pore water. Part 1 in this series of papers is concerned with the mathematical and physical modeling of the multi-material flow associated with vibro-injection pile installation. This model is the backbone of a new multi-material arbitrary Lagrangian-Eulerian (MMALE) numerical method presented in Part 2.DFG, 76838227, Numerische Modellierung der Herstellung von Rüttelinjektionspfähle

How, where, and when do radial faults grow near salt diapirs?

We examine three-dimensional seismic data from the Santos Basin, offshore Brazil, to determine how, where, and when radial faults grow near a salt diapir. We show roof stretching alone cannot account for the large heights and lengths of the kilometer-scale radial faults, suggesting stock widening ('stem push'), a mechanism implied in numerical models but not yet recognized in natural examples, played a pivotal role in fault formation. We suggest that, when a diapir is covered by a roof, radial faults form due to roof stretching, extending no further than the limit of the drape folding. The roof may then be shouldered aside and the faults buried along the stock flanks, exposing these strata to stem push–related stresses that may then re-activate preexisting, or form new, radial faults. We suggest the causal mechanism for radial fault formation will likely change as roof thickness varies during diapirism, with this reflecting the ratio between sedimentation rate and salt volumetric flux