Print Email Facebook Twitter Toe structure for rubble mound breakwaters: Analysis of toe bund design tools and a method for toe rock stability description Title Toe structure for rubble mound breakwaters: Analysis of toe bund design tools and a method for toe rock stability description Author Baart, S.A. Contributor Stive, M.J.F. (mentor) Verhagen, H.J. (mentor) Uijttewaal, J.S.W. (mentor) Bos, J.P. van den (mentor) Corporate name Royal Boskalis Westminster Faculty Civil Engineering and Geosciences Date 2008-06-27 Abstract This thesis investigates the stability of rocks in toe bunds for rubble mound breakwaters. Presently recommended design tools lack a reasonable degree of accuracy to assess required toe element dimensions. The goal of this research is to improve the insight in the physical process related to stability of toe bund elements under wave load. Analysis of presently recommended methods led to the following conclusions: a. The formula of Van der Meer is no improvement of the formula of Gerding. b. Both methods use an inappropriate relation between stability and damage. c. The method of Van der Meer may often underestimate the required toe rock size. A new hypothesis is formulated to describe toe rock stability. The concept for the model of this study is based on two steps: Step 1: Assessment of the local water motions at the toe bund. The amplitude of local velocity is calculated by summation of the contributions of the incoming wave and down rush, taking a phase difference into account. Step 2: Description of the critical load on a toe rock. The Rance/Warren stability criterion is used with a theoretical adaptation that accounts for porous outflow. Coupling these two steps implies that a rock will move if the occurring velocity exceeds the critical velocity. An evaluation of the hypothesis is performed and the model is fitted to available test data. The accuracy of stability assessment is increased with respect to previous methods. The model of this study has more resemblance to the test data and can be used to predict the required toe rock size in design. This is verified for the applicability range of the data set of Gerding. Subject toe bundrubble mound breakwaterrock stabilitywater motioncoastal structure To reference this document use: https://doi.org/10.4233/uuid:1eceacb8-23c8-48ff-9cec-772434559b00 Publisher TU Delft, Civil Engineering and Geosciences, Hydraulic Engineering Related item https://doi.org/10.4121/uuid:4d63df11-914d-430f-989b-16c09e0bd743 Part of collection Student theses Document type master thesis Rights (c) 2008 S.A. Baart Files PDF ceg_baart_2008.pdf 3.52 MB Close viewer /islandora/object/uuid:1eceacb8-23c8-48ff-9cec-772434559b00/datastream/OBJ/view