Opdrijven, opbollen, opbarsten: Improving the uplift model for the assessment of internal erosion

Internal erosion is a frequent cause of dike failure, also known as piping or backward erosion. Uplift is considered a submechanism of internal erosion, together with heave and piping, where all three submechanisms must occur for the dike to reach a failure condition. The principle of the uplift phenomenon is straightforward: it occurs when high...

The unexpected softening of the undrained shear strength of organic and silty clays in Rhine delta: a conceptual study: Determining the Undrained Shear Strength of soft Dutch soils using conventional laboratory equipment

The current Dutch norms for the macro-stability of ood protection embankments and more specifically the determination of SHANSEP parameters has been subject of debate since its implementation in 2017. The main concerns arise from the apparent over-conservative nature of the guidelines and the apparent underestimation of shear strength of organic...

Interaction between the failure mechanisms backward erosion piping and slope instability: Identification and quantification of interactions between failure mechanisms of a levee

With the shift of the safety standards for levees from exceedance probability (standard 1996) to flooding probability (new standard), the part of the levee failure process after the initial occurrence of a failure mechanism becomes more important for the calculation of the strength and thus, reliability of the levee cross-section. Interactions...

The detection of deformation on vegetated dikes using InSAR

Almost four million people in the Netherlands who live below sea level are protected by 17000 km of dikes against the water. Since deformation can be an indicator of a developing failure mechanism, information about this parameter can help authorities to detect weak spots in the dutch water defense structures. <br/>In this research, Radar...

A method to calculate the probability of dike failure due to wave overtopping, including the infragravity waves and morphological changes

In this thesis, a method was developed, with which the infragravity waves and morphological changes of a sandy foreshore are included in the calculation of the probability of dike failure due to wave overtopping. Constructing a natural foreshore in front of the dike can be an attractive and innovative method to decrease the failure probability....

Design of mangrove rehabilitation projects on tropical coasts

Mangroves have been proven to be an asset to coastlines because of their myriad advantages relating to coastal protection and stability. Unfortunately, in the past, due to economic necessities or other reasons, many of these mangrove swamps in tropical areas came under threat and were subsequently destroyed. As the awareness about the positive...

Reinforced grass on inner dike slopes

This thesis shows a set of equations that define the micro-stability and macro-stability of reinforced grass revetments with geosynthetics on inner dike slope during an overtopping event. At micro-stability level, it has been analyzed that the equilibrium in a soil particle using the criterion of incipient motion of soil particle. The forces in...

Levees and levee evaluation, the Dutch and US practice compared

After Katrina flooded New Orleans, California was identified as the next area where such a major disaster could happen. Situated between the Sierra Nevada and coastal mountain ranges Californias Central Valley is characterized by its flatness and dominated by agriculture as well as large cities as Sacramento. The Sacramento River and San Joaquin...

Hydraulic properties of PUR-revetments compared to those of open stone asphalt revetments - Some mechanical properties of elastocoast for safety investigations of dikes (VTV2004)

Erosion processes on dike slopes

Erosion processes are divided in two parts, whereas first process is detachment process and second process is transport of detached soil. The main function of grass cover is to avoid detachment. Therefore certain strength is necessary to execute this assignment. Resistance of grass covers are affected by several parameters. The influencing...

Toepassen van duikers in kaden in uiterwaarden

In 1993 and 1995 the Netherlands were started by two flood waves. They did not cause much damage in the floodplains, but they made clear that it should not be taken for granted that the Netherlands are protected for floodings. Therefore in 1996 the policy 'Ruimte voor de rivier' came to effect. In this policy measures are sought to protect the...

Stabiliteit van steenzettingen: Beschouwing van een dijkbekleding als een verend ondersteunde buigligger

Bij het bepalen van de sterkte van een dijkbekleding wordt tot nu toe uitgegaan van een losliggend blok als ondergrens voor de stabiliteit. In dit rapport wordt een steenzetting als een ligger beschouwd, waarbij er een normaalkracht opgebouwd wordt, die voor een aanvullende sterkte van de bekleding zorgt. De mate waarin dit gebeurt, is...