Hydroabrasion by High-Speed Sediment-Laden Lows in Sediment Bypass Tunnels
| LEADER | cam a22 4500 | ||
|---|---|---|---|
| 001 | 528781758 | ||
| 005 | 20201202084607.0 | ||
| 007 | cr unu---uuuuu | ||
| 008 | 180924s2018 xx sm 000 0 eng | ||
| 024 | 7 | 0 | |a 10.3929/ethz-b-000273498 |2 doi |
| 035 | |a (ETHRESEARCH)oai:www.research-collecti.ethz.ch:20.500.11850/273498 | ||
| 100 | 1 | |a Müller-Hagmann |D Michelle | |
| 245 | 1 | 0 | |a Hydroabrasion by High-Speed Sediment-Laden Lows in Sediment Bypass Tunnels |h [Elektronische Daten] |c [Michelle Müller-Hagmann, Robert M. Boes (Supervisor), Ismail Albayrak (Supervisor), Eugen Brühwiler (Supervisor), Frank Jacobs (Supervisor), Christian Auel (Supervisor)] |
| 260 | |a Zurich |b ETH Zurich |c 2018 | ||
| 300 | |a 306 p. | ||
| 502 | |a Doctoral Thesis | ||
| 506 | |a Open access |2 ethresearch | ||
| 520 | 3 | |a Reservoir dams impound flowing water to balance a fluctuating water supply and demand. All reservoirs situated on natural watercourses are subjected to sediment inflow. Water-carried sediments continuously settle in the quiescent environment of a reservoir resulting in accumulation, negatively affecting their functions. Sediment bypass tunnels (SBTs) are an effective measure against reservoir sedimentation by diverting sediment-laden water past the dam and allowing for re-establishing the natural sediment continuity. However, high-speed sediment-laden flows in SBTs can cause severe invert abrasion, putting SBT operation at risk and provoking high maintenance costs. Mitigation of hydroabrasion problems requires a better understanding of governing parameters, namely flow characteristics, particle and invert material properties, sediment transport and their interactions. Despite a large number of small-scale laboratory studies on hydroabrasion, upscaling of their results to prototype scale is questionable due to a lack of prototype data. Therefore, this study aims at filling this research gap by in-situ investigation of hydroabrasion in combination with laboratory tests. Various invert materials, i.e. concretes, granite, steel and cast basalt, were installed in the Solis, Pfaffensprung and Runcahez SBTs in Switzerland. The abrasion patterns and rates, flow conditions, sediment transport rate and sediment properties in the rivers, reservoirs and SBTs were determined and their interrelations were analyzed with an emphasis on hydroabrasion, bypass efficiency and operating regime of the SBTs and respective reservoirs. The results of the abrasion measurements showed that hydroabrasion is a self-intensifying process, triggered by discontinuities and constructional weaknesses resulting in characteristic material-dependent abrasion patterns. In addition to this, the abrasion pattern was found to be affected by 3D flow structures induced by either tunnel bends or low tunnel width to flow depth ratios. The resulting ratio of maximum to spatially averaged abrasion depths ranged from 1.6 to 2.2, which is of prime importance regarding the dimensioning of the invert material thickness. Invert material selection and dimensioning requires cost-effectiveness analysis, which is a function of abrasion rate, material cost, abrasion conditions and target life time. For the first, three existing abrasion prediction models were evaluated and calibrated based on the present field data. The resulting abrasion coefficients generally agreed with literature data. However, application of material-specific abrasion coefficients was found to significantly enhance the model prediction accuracy and is therefore recommended. Based on that, present cost-effectiveness analysis revealed that hard rock and (ultra-)high-strength concretes are more suitable for long-term application under severe abrasion conditions, whereas less expensive materials are more economical for moderate to low abrasion conditions or short-term application, despite the lower abrasion resistance. The present study revealed that the bypass efficiency of a SBT strongly depends on the location of the SBT intake and the operational regime of both the reservoir and the SBT. To achieve an optimum bypass efficiency, the SBT and reservoir operations need to be coordinated and optimized, which requires a continuous and real-time monitoring of the hydraulic and sediment transport conditions in the river, reservoir and SBT. Overall, this study provides new insights into the flow and sediment transport characteristics in SBTs and reservoirs and advances the understanding of hydroabrasion processes in high-speed sediment-laden open channel flows. The main results are the applicable recommendations with a focus on hydroabrasion and bypass efficiency, contributing to a sustainable and efficient design and operation of SBTs. | |
| 540 | |a In Copyright - Non-Commercial Use Permitted |u http://rightsstatements.org/page/InC-NC/1.0 |2 ethresearch | ||
| 690 | 7 | |a sediment bypass tunnel |2 ethresearch | |
| 690 | 7 | |a hydroabrasion |2 ethresearch | |
| 690 | 7 | |a prototype study |2 ethresearch | |
| 690 | 7 | |a reservoir sedimentation |2 ethresearch | |
| 690 | 7 | |a experimental study |2 ethresearch | |
| 690 | 7 | |a sediment management at dam reservoirs |2 ethresearch | |
| 690 | 7 | |a Civil engineering |2 ethresearch | |
| 690 | 7 | |a Earth sciences |2 ethresearch | |
| 700 | 1 | |a Boes |D Robert M. |e Supervisor |4 dgs | |
| 700 | 1 | |a Albayrak |D Ismail |e Supervisor |4 dgs | |
| 700 | 1 | |a Brühwiler |D Eugen |e Supervisor |4 dgs | |
| 700 | 1 | |a Jacobs |D Frank |e Supervisor |4 dgs | |
| 700 | 1 | |a Auel |D Christian |e Supervisor |4 dgs | |
| 856 | 4 | 0 | |u http://hdl.handle.net/20.500.11850/273498 |q text/html |z WWW-Backlink auf das Repository (Open access) |
| 898 | |a BK020353 |b XK020053 |c XK020000 | ||
| 908 | |D 1 |a Doctoral Thesis |2 ethresearch | ||
| 949 | |B ETHRESEARCH |F ETHRESEARCH |b ETHRESEARCH |j Doctoral Thesis |c Open access | ||
| 950 | |B ETHRESEARCH |P 856 |E 40 |u http://hdl.handle.net/20.500.11850/273498 |q text/html |z WWW-Backlink auf das Repository (Open access) | ||
| 950 | |B ETHRESEARCH |P 100 |E 1- |a Müller-Hagmann |D Michelle | ||
| 950 | |B ETHRESEARCH |P 700 |E 1- |a Boes |D Robert M. |e Supervisor |4 dgs | ||
| 950 | |B ETHRESEARCH |P 700 |E 1- |a Albayrak |D Ismail |e Supervisor |4 dgs | ||
| 950 | |B ETHRESEARCH |P 700 |E 1- |a Brühwiler |D Eugen |e Supervisor |4 dgs | ||
| 950 | |B ETHRESEARCH |P 700 |E 1- |a Jacobs |D Frank |e Supervisor |4 dgs | ||
| 950 | |B ETHRESEARCH |P 700 |E 1- |a Auel |D Christian |e Supervisor |4 dgs | ||