Damage on rock slopes under wave attack

Damage on rock slopes under wave attack

Papadopoulos, D.

Verhagen, H.J.
Van den Bos, J.P.

Civil Engineering and Geosciences

Hydraulic Engineering

2012-03-02

The aim of this study is the particularisation of the accuracy margins for the determination of the damage level in the experimental plan proposed by Remon Kik at his thesis for the study of Notional Permeability of breakwaters “The experimental research of the permeability factor P”. The evaluation of the proposed technique took place by means of comparisons between different test cases in order to specify the existence of similarities in the statistical behaviour of original tests and their repetitions. Therefore, statistical tests are used to examine the behaviour of the individual tests not only individually, but also in combination with the rest of the test components. For the selected statistical and computational approaches the optimum measurement space step had to be specified. Therefore, a comparison took place between measurements every 5cm and every 10cm. The length of the confidence intervals was used to quantify the difference in accuracy and the two fundamental non parametric tests of Mann-Whitney U/ Wilcoxon W and Kolmogorov-Smirnov (theoretical explanation Appendix B) were applied in order to qualitatively investigate the magnitude of the behavioral change of the distribution due to the addition of the in-between measurements (profile measurements every 5cm). The analysis showed that although the smaller measuring step increased the accuracy at about 10 -30% the differences in absolute damage values were trivial. Furtherupon, differences among tests that occur in the plunging and in the surging area were examined and tendencies were recorded. The outcome showed that an imperceptible difference occurs. The deviation was steadily bigger for the case of tests located in the plunging area (28% in contrast to 21.5% of the surging area), but this difference is considered to be trivial. Finally, the accent was paid in the limitations of the available means and equipment. The observed higher damage values at the sides were investigated. The 13 cross sections of the structure were divided into two groups of side and middle cross sections and comparisons between them were accomplished. Then the influence of the boundary measurements was quantified in order to interpret any existing tendencies of higher damage values and local irregularities that may affect the output of the computations. In fact, the data analysis showed that the variation of damage values at the side cross sections was for all the cases larger than the middle ones. In half of the cases the difference was significant while for the other half, difference occurred, but with a lower magnitude.

breakwater
permeability
model tests

http://resolver.tudelft.nl/uuid:e7ef8d1e-6f9a-437f-82a0-581c935055c1

https://doi.org/10.4121/uuid:fe47c333-2965-4466-9f31-c2a4fac1709d

Student theses

student report

(c) 2012 Papadopoulos, D.