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 effect of leakage on backward erosion piping: A modelling study in 2D and 3D

In the Netherlands, dikes are the most commonly used structures to retain water and provide safety against flooding. In order to ensure the safety of these dikes against a number of different failure mechanisms such as backwards erosion piping, wave overtopping and macro stability, a detailed safety assessment has been created. The focus of this...

Length-Effects in Reliability Analysis of Internal Erosion in Earthen Dikes

In this master thesis the current Dutch method of combining failure probabilities at different spatial scales is researched. This method is used in the Dutch flood risk analysis of earthen dikes to assess the probability of flooding. Currently, probabilities of flooding for geotechnical failure mechanisms are obtained which are not considered to...

Understanding Piping using Pore Pressure Observations: (Abstract)

Physical measurements of the backward erosion piping process: (Paper and Abstract)

A novel laboratory device is presented, in which the process of backward erosion piping is observed in cylindrical sand samples oriented horizontally. The cylindrical shape of the testing device constrained the location of the erosion path to the top of the sample, thereby allowing pore pressure measurements to be made in both the eroded pipe...

Laboratory Tests for Backwards Piping Erosion

The U.S. Army Engineer Research and Development Center (ERDC) is conducting research to investigate internal erosion, specifically backward erosion piping, by use of laboratory-scale model testing to understand and properly capture the physics of the problem. Preliminary results show that lower void ratio models, using poorly-graded soils with a...

Determination of Spatial Variability in d70 Grain Size Values Using High Density Site Measurements

Research to the failure mechanism piping (internal, backward erosion) in the Netherlands shows that the dikes require costly berms to meet the required safety standards. According to the Sellmeijer piping-formula, the d70 (70%-quantile of the grain size distribution by weight) is an important parameter in the resistance against piping. Therefore...

On reducing piping uncertainties: A Bayesian decision approach

Dikes and levees play a crucial role in flood protection in deltaic areas such as the Netherlands. Internal erosion piping or under-seepage is a major cause of levee failures and a main contributor to the probability of failure of river levees due to the large (mostly geotechnical) uncertainties. The present thesis investigates how geotechnical...

Advances in reliability analysis of the piping failure mechanism of flood defences in the Netherlands

Piping is one of the main failure mechanisms for flood defences. This paper gives an overview of recent developments in the reliability analysis for this mechanism in the Netherlands. These comprise new approaches in the treatment of heterogeneity of the subsoil with respect to the failure process, the inclusion of information from field...

The Weakest Link: Spatial Variability in the Piping Failure Mechanism of Dikes

Piping is an important failure mechanism of flood defense structures. A dike fails due to piping when a head difference causes first the uplift of an inland blanket layer, and subsequently soil erosion due to a ground water flow. Spatial variability of subsoil parameters causes the probability of piping failure to increase, often to unacceptable...

Piping in loose sands – the importance of geometrical fixity of grains

Piping is one of the possible failure mechanism for dams and levees with a sandy foundation. Water flowing through the foundation causes the onset of grain transport, due to which shallow pipes are formed at the interface of the sandy layer and an impermeable blanket layer. In the past, the mechanism has been investigated predominantly in...