Survey of the Ridracoli Dam: UAV–based photogrammetry and traditional topographic techniques in the inspection of vertical structures

The inspection of strategic works such as dams is of vital importance both for their maintenance and for the safety of downstream populations. The reduced accessibility, both for uptake needs and for their strategic nature, and the large time needed for an inspection by traditional method do not facilitate the investigation of this type of structures. The new unmanned aerial vehicle (UAV) technology, equipped with high-performance cameras, allows for rapid photographic coverage of the whole dam system. Apart from the placement on the structure of a high number of markers, the correct geo-referencing and validation of the model also requires an important terrestrial topographic campaign by total station, Global Positioning System and laser scanner. Punctual, linear and surface analysis shows the high accuracy of the drone acquiring technique. The product is suitable for a detailed survey of the conservation status of the materials and the complete metric reconstruction of the dam system and the adjacent land. The present work explains firstly a UAV acquisition and then the first dense point cloud validation procedure of a concrete arch gravity dam. The Ridracoli dam is the object of the survey, located in the village of Santa Sofia in central Italy

Spillway discharges by modification of weir shapes and overflow surroundings

Almost all spillways of mid-size dams in Korea are overflow weir. To investigate the flood control capacity of overflow spillway, 3D numerical simulations were analyzed the discharge of a dam spillway for different weir shapes. Hydraulic model experiments, downsized as scale factor of 40 to 1 by Froude similitude were also carried out to verify the numerical results. Overflow phases and discharges of the linear labyrinth weir and the curved labyrinth weir were compared with those of the linear ogee weir. It was found that the discharge of the labyrinth weir was 71 % greater than that of the linear ogee weir at low reservoir elevation because the labyrinth weir had a longer effective length. However, as the elevation of the water surface rose, the discharge slope of the labyrinth weir became milder by submergence and nappe interference in the side channel. Structural modification of the overflow surroundings such as changing the approaching channel elevation, lowering the bed elevation of the side channel, and moving the weir structure toward the reservoir were also considered to examine the discharge capacity of the spillway. Lowering the bed elevation of the side channel was found to be the most effective option.OAIID:RECH_ACHV_DSTSH_NO:T201636126RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A080988CITE_RATE:1.569FILENAME:pub09_Seo_etal_2016EES.pdfDEPT_NM:건설환경공학부EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/9c948ad0-91a5-4559-8ff8-c4a827fb6c67/linkN