On the modelling of the unstable breaching process

On the modelling of the unstable breaching process

Weij, D. (TU Delft Offshore and Dredging Engineering)

van Rhee, C. (promotor)
Keetels, G.H. (copromotor)

Delft University of Technology

2020-04-02

Breaching is an important production mechanism for stationary suction dredgers. It is a process occurring in submerged sandy slopes, which mostly occurs in dense sandy soils with a low permeability. The process is initiated by the formation of a slope under water, whose angle is steeper than the internal friction angle, called the breach face. For dredging related breaching, this steep slope is created by a suction dredger, but it can also be formed after initial shear failure, caused by over steepening due to erosion, an earthquake, or an outwardly directed water flow. During breaching process, this steep slope is semi-stable due to negative pore pressure. Instead of a shear failure, particles are released one by one from the breach face, making it seem like the breach face is slowly moving backwards. The released particles form a density current that flows away from the breach face, and can be collected by a stationary suction dredger. When the size of the breach face increases over time, we have an unstable breach.

Dredging
numerical modelling
turbidity currents
breaching

https://doi.org/10.4233/uuid:5d4e0db3-c50c-4f33-b261-c3ec7514139e

Institutional Repository

doctoral thesis

© 2020 D. Weij