The study of the characteristics of waves generated by the collapse of rock masses in dam reservoir walls is of great importance. Factors influencing the wave flow over the body and crest of a dam include the length, height, and speed of the waves generated by the collapse of rock masses due to various factors. For this reason, in the present study, the wave parameters mentioned were measured for the first time using laser surface profiling in a pool with dimensions of 12.5 meters in length, 6.5 meters in width, and 1 meter in height at Zanjan University, Iran, due to the collapse of a mass in this reservoir. The experiments were conducted using a sliding mass weighing 200 kilograms and for a water depth of 75 cm. The laser setup consisted of two arrays (with a 76 cm distance between them), where each array contained 15 lasers arranged in pairs facing each other. Using these lasers and a DSLR camera, after the mass was dropped onto the inclined surface, the variations in wave height over time were recorded. Then, using the recorded images and laser surface profiling, the wave height was first measured, and then, using the changes in height, the wavelength was calculated. Following this, by measuring the time it took for the wave to pass in front of the two laser arrays, the wave speed was also obtained. It is worth noting that the camera's frame rate was 0.04 seconds. The experimental results indicate that the measured wave speed using the proposed method was 2.67 meters per second, while the wave speed calculated using the wave speed formula (C=√gh) was 2.71 meters per second, showing a difference of 1.48%, which demonstrates the high accuracy of the proposed measurement method.
Keywords : Mass fall,impact waves,wavelength,wave speed,laser surface profilometry