Investigation of hydraulic responses of rubble- mound revetments under irregular sea wave attack

In this research hydraulic responses of rubble-mound seawalls include irregular wave run up, rundown, reflection and overtopping were investigated. Method of research was based on physical mode ling. Experiments were done for three cross section of seawalls in Soil Conservation and Watershed Management Research Institute (SCWMRI) wave flume, during 2000 to 2002. The wave flume equipped with a Dill wave generation system. The wave generation system is including paddle, power pack, hardware and software divisions that can generate both regular and irregular waves. Wave and structural parameters (e.g. type of Armour layer materials, slope of structure, freeboard, grading and permeability and significant wave height, mean wave period and storm duration) for investigation of hydraulic responses that mentioned above were changed in experiments. Irregular waves with JONSWAP wave spectrum were used in all experiments. Three types of Armour layer materials (stone, Tetrapod and Antifer blocks), four structure's seaward slopes (equal to 1:1.25, 1:1.5, 1:2.0 and 1:3.0.), three water levels (respectively M.H.W., M.W.L. and M.L.W.), three grading class of stone (D851D15 = 1.82, 1.44 and 1.1) and three notional permeability of the structure (P = 0.5, 0.4 and 1.1) were chose to fmd Effect of structural parameters on hydraulic responses. For investigation of wave conditions effect on hydraulic responses of rubble mound seawalls, During tests procedure, a wide range of significant wave height and mean wave period (with steepness of 0.01 to 0.1) were generate and also the same storm evidence with duration of 1000 waves (respectively Istl000, 2ndl000 and 3rdl000 waves) for each of them. During each experiment, data collection and acquisition were done with both observation and measurements. Four wave height meter sensors measured water level's fluctuations with 40 Hz data entry frequency, for wave height, run up, rundown and reflection recording. A small tank was installed behind of the model to measuring the volume of wave overtopping in each experiment. In order to changing above parameters, finally 484 tests were done. Results of this research were shown as non-dimensional design charts and graphs and new prediction relations and equations.