Zur Bemessung von verzahnten Setzsteindeckwerken gegen hydrodynamische Belastungen

摘要

Predicted mean sea level rise and increase of storm surge frequency and magnitude due to climate change require a strengthening of coastal protection. Therefore, a revetment system is needed that is characterized by both high resistance against external loading and low material costs. Interlocking block revetments, which form a subgroup of block revetments, represent one possible solution. The single blocks are interlocked for example by a horizontal or a vertical connection. Higher strength against external loading compared to loose block revetments can be expected. Although interlocking revetment blocks are successfully in use at slopes exposed to waves and currents since decades, there are no studies available neither in the national nor in the international literature, which evaluate the strength of interlocking block revetments. The objective of this study is the development of a design approach for interlocking block revetments against hydrodynamic loading and the evaluation of the stability increase due to the interlocking. In order to achieve these objectives, the equation for the limit state for the uplift loading due to wave attack, which represents the main failure mechanism of interlocking block revetments, has to be determined. Within the equation the resistance of the interlocking block and the stress due to the wave attack has to be compared. The determination of the resistance is based on pull out tests, performed under laboratory conditions and on pull out tests conducted on a wave loaded revetment within large scale model tests performed at the Large Wave Channel Hannover (GWK). These tests show that an additional interlocking force due to particles occurs. These particles are washed in the gaps between the inter-locking blocks due to the waves and the following dewatering processes. The determination of the loading due to wave attack is based on data from large scale model tests performed at the GWK. The analysis of the data reveals a relationship between the parameters of the incoming wave and the caused uplift load. In the following these results are combined to a design approach. It supports the design of interlocking block revetments depending on a predefined design wave.An application of the design formula to the Standard Verkalit® revetment block shows, that the stone height can be reduced by the factor of 2.91 by using interlocking blocks.