The effect of a dragging anchor on a horizontal layer of rockfill: A Prototype and a Scale Model Test

Quantifying the penetration depth of a dragging anchor on a horizontal layer of rockfill provides the possibility to optimize the layer thickness of rockfill layers with a protective function. Current research on this subject is limited and is often aimed at anchor capacities in sand and clay. Penetration behaviour in rockfill is mainly...

Validation and Optimization of a Design Formula for Stable Geometrically Open Filter Structures

Granular filters are used for protection against scour and erosion of base material. For a proper functioning it is necessary that at the interfaces between the filter structure, the subsoil and the water flowing above the filter structure no material will be transported. Different types of granular filters can be distinguished, this paper...

Interface stability of granular filter structures under currents

Granular filters are used for protection of structures against scour and erosion. For a proper functioning it is necessary that the interfaces between the filter structure, the subsoil and the water flowing above the filter structure are stable. Stability means that there is no transport of subsoil material through the filter to the water above...

Stone Stability in Non-uniform Flow

This paper presents the results of an experimental study on stone stability under nonuniform turbulent flow, in particular expanding flow. Detailed measurements of both flow and turbulence and the bed stability are described. Than various manners of quantifying the hydraulic loads exerted on the stones on a bed are extensively reviewed and...

Low-mobility transport of coarse-grained bed material under waves and currents

The Paintal (1967) formula can be used to estimate transport rates of coarse-grained bed material (such as stones from a bed protection) under low hydraulic loads just above the threshold of motion; the application however is limited to steady currents. This paper presents research aimed at extending the range of application to a combination of...

Scour around an offshore windturbine

During the construction of the first Dutch offshore wind farm prototype measurements were performed. These measurements were aimed to monitor the behaviour of the granular filter layer of the scour protection around the mono-piles upon which the wind turbines are founded. These measurements were compared to scale model test results and...

Stone stability under decelerating open-channel flow

The current research is aimed at finding a proper relation between flow forces acting on the bed and the bed response. To this end, experiments were carried out in which both the bed response (quantified by a dimensionless entrainment rate) and the flow field (velocity and turbulence intensity distributions) are measured. The three available...

Stone stability under non-uniform flow

The current research is aimed at finding a dimensionless stability parameter for non-uniform flow in which the effect of turbulence is incorporated. To this end, experiments were carried out in which both the bed response (quantified by a dimensionless entrainment rate) and the flow field (velocity and turbulence intensity distributions) are...

Void porosity measurements in coastal structures

The paper describes the use of two fundamental design parameters, the void porosity and layer thickness in rock armour constructions. These design parameters are very sensible for factors such as the boundary definition of a rock layer, rock production properties, intrinsic properties and construction properties. Differences in the value of the...

A study of the behaviour of and the forces in a bed protecting mattress: The falling apron

In many cases the bottom around a structure that is exposed to current has to be protected by a mattress. The purpose of the mattress is to protect the soil besides the structure from erosion and scour, thus preserving the strength of the foundation of the structure. Examples are the bottom protection around bridge piers, along guide bunds and...

Probabilistische analyse van onzekerheden bij ontwerp en uitvoering van een enkellaagse geometrisch open filterconstructie in een open waterloop

Aan het begin van deze studie bestond onduidelijkheid over de vraag in hoeverre het eventueel falen van een geometrisch open filterconstructie in een open waterloop nu het gevolg zou zijn van onzekerheden met betrekking tot het bij het ontwerp gehanteerde rekenmodel, of juist van onzekerheden met betrekking t o t onnauwkeurigheden bij de bouw...

Steenstorten: Voorspelling van het stort als gestort wordt vanuit een vast punt

In the construction of dams and in protection of civil engineering works in water courses often use is made of dumped stones. The dumping process can be divided in two stages. During the first stage the resulting mound of stones on the bottom of the water course is built up vertically. In the second stage the stones are under the angle of repose...

Introduction to bed, bank and shore protection

Flow (loads, stability, erosion) Porous flow (general, filters), waves (loads, stability, erosin), ships, protections, construction and maintenance, design.

Introduction to bed, bank, shore protection

Loads (flow, waves, ships, porous flow), Erosion (flow, remainder) Load reduction, stability (flow, waves, porous flow), Protections, construction and maintenance, design.

Revetments 2