Jet-aided venting of cohesive sediment deposits from Wushe Reservoir: feasibility study using small-scale experiments

• Main Authors: Salah H. Khadeeda, 古涵山
• Other Authors: Hervé Capart
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/01867598009448522345

碩士 === 國立臺灣大學 === 土木工程學研究所 === 99 === ABSTRACT In this thesis, field investigation and laboratory experiments are performed to investigate the feasibility of underwater jetting as an aid to reservoir de-siltation. For understanding jetting and underwater dredging technique, we reviewed ROVs’ technology, undersea trenching technique and dredging platform-boat of Shimen Reservoir. Wu-She Reservoir was selected as reference filed case. We reviewed current plan of developing dam, collected samples from the bottom of reservoir and analyzed its characteristics. Small-scale 1D experiment, were conducted to observe cohesive bed response to point-jet. In this experiments, a driven carriage to move an oblique point-jet along a horizontal bed of cohesive Wu-She Reservoir’s soil. The resulting jetting flow, trench shape and turbid cloud are observed from the side using a digital camera, and from the top using a medical ultrasound probe. The laboratory model is used to measure trench shapes for a range of jet flow rates and advancing speed. The depth and advancing speed for our cohesive silt-mud mixture are then compared to previous experimental measurements for non-cohesive sand. Next we conducted experiments on 2D laboratory model to scale 1:1000 of Wu-She Reservoir. To compare the efficiency of sediment venting with and without jetting. A first set of experiments was conducted in a 1D narrow channel. Then, a second set of experiments was conducted in 2D channel. For 2D model Sinlaku typhoon data’s was selected as an initial condition for the set of experiments. Then concluding our thesis simulating topography of reservoir before and after flood event to observe venting outlet’s efficiency aided by point-jet.