scholarly journals Numerical Evaluation of a 70-m Deep Hydro-Power Station Foundation Pit Dewatering

2021 ◽  
Author(s):  
Jianxiu Wang ◽  
Yansheng Deng ◽  
Xiaobo Wang ◽  
Xiaotian Liu ◽  
Nianqing Zhou
Keyword(s):  
Groundwater Level ◽  
Slope Failure ◽  
Numerical Models ◽  
Water Inrush ◽  
Cutoff Wall ◽  
Power Station ◽  
Foundation Pit ◽  
Hydro Power ◽  
Second Stage ◽  
Pumping Wells

Abstract The average depth of Yamansu hydropower station foundation pit is 70 m. The foundation pit was excavated with five-level slopes. The lowering of groundwater level is significant for excavation. Drainage and pumping were adopted in dewatering. Pumping tests were performed to reverse hydraulic parameters and calibrate numerical models. Numerical simulations were performed to evaluate the dewatering scheme. In the first stage, powerhouse tailrace canal was excavated and utilized as a drainage channel to lower the groundwater level. The drawdown and hydraulic gradient were evaluated to prevent potential water inrush, erosion, piping, and slope failure. In the second stage, cutoff wall and pumping wells were evaluated to lower the groundwater level. The influences of depth, permeability, and thickness of the cutoff wall were evaluated. Dewatering scheme was revised accordingly based on the evaluation. The optimized dewatering scheme, which can be referred by similar engineering, was performed and verified successfully.

scholarly journals Generator Assessment of Hydro Power Station Adequacy after Reconstruction from Classical to HIS SF6 Substation

2017 ◽  
Vol 7 (2) ◽  
pp. 729
Author(s):  
Srete Nikolovski ◽  
Goran Slipac ◽  
Emir Alibašić
Keyword(s):  
State Space Model ◽  
Annual Reports ◽  
Power Station ◽  
Hydro Power ◽  
Space Model ◽  
System Operator ◽  
Adequacy Assessment ◽  
High Level ◽  
Maintenance Process ◽  
Reliability And Availability

<p>Reliability analysis of substations and generator assessment of power plant stations are very important elements in a design and maintenance process. This paper presents a generator adequacy assessment of a classical “H” scheme for an open conventional substation, which is often used, and a new HIS - High Integrated Switchgear with SF6 gas isolation. Generator adequacy indices of both types of classical and HIS switchgear were compared and the results showed a high level of reliability and availability of the HIS presented substation. The input data were the annual reports of Croatian TSO-Transmission System Operator (HOPS) and statistics of operation events of Croatian National Electricity (HEP Inc.). For the HIS substation, the input reliability data were used from relevant international literature since only few of HIS substations are installed in Croatia. The generator is modelled with a three-state Markov state space model and Monte Carlo simulations were used for the generator assessment analysis. Adequacy indices LOLP and EDNS were obtained using DIgSILENT software.</p>

scholarly journals Shear Stress Analysis and Crack Prevention Measures for a Concrete-Face Rockfill Dam, Advanced Construction of a First-Stage Face Slab, and a First-Stage Face Slab in Advanced Reservoir Water Storage

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Kongzhong Hu ◽  
Jiankang Chen ◽  
Dong Wang
Keyword(s):  
Shear Stress ◽  
Internal Stress ◽  
Water Storage ◽  
Water Levels ◽  
Power Station ◽  
Reservoir Water ◽  
Second Stage ◽  
Rockfill Dam ◽  
Concrete Face ◽  
Concrete Face Rockfill Dam

Due to the demand in flood season for power generation, the first-stage face slab of a high concrete-face rockfill dam often must be constructed ahead of schedule, and advanced water storage is needed for the reservoir. Since the dam-body filling has not yet been completed at this point, the internal stress of the first-stage face slab is more complicated than that of normal construction. Taking Buxi Power Station as an example, the first-stage face slab temporary construction seam showed large areas of shear stress damage during the rise in reservoir water levels during the second segment of the second construction stage. The concrete-face slab showed large-piece brittle bulging, and the steel rebar was exposed and developed contortional deformation. Based on the monitoring data for Buxi Power Station along with the first-stage fracture characteristics of Shuibuya concrete face, this paper applied a numerical analysis to conduct research on the causes of fracture mechanics. The results indicate that the cracks occurred on the face slab during the second segment of second-stage water storage primarily due to the advanced concrete pouring of the first-stage face slab; during the first stage of reservoir water storage, the internal stress of the first-stage face slab was not reduced or eliminated prior to second-stage face slab pouring. Thus, with the rise in the reservoir water level, the shear stress increased continuously, eventually leading to partial large-scale shear stress failure of the first-stage face slab. The research results provide important references for the design and construction of concrete-face rockfill dams.

Too close for comfort: a fishway exit and a hydro-power station inlet

2010 ◽  
Vol 61 (1) ◽  
pp. 23 ◽  
Author(s):  
Ivor G. Stuart ◽  
John D. Koehn ◽  
Tim A. O'Brien ◽  
John A. McKenzie ◽  
Gerry P. Quinn
Keyword(s):  
Management Strategies ◽  
Field Testing ◽  
High Water ◽  
Fish Passage ◽  
Native Fish ◽  
Power Station ◽  
Hydro Power ◽  
Murray River ◽  
Eastern Australia ◽  
Radio Transmitters

A major environmental issue for hydro-electric power generation is passage of fish through turbines, or entrainment onto trash racks. At Yarrawonga Weir, on the upper Murray River in south-eastern Australia, the positioning of a fish lock resulted in the potential for upstream migrating fish to be swept back into the adjacent power station by cross flows. In 2004, a 4.5-m long steel extension flume was attached to the exit to alleviate this problem. To determine the fate of native fish after exiting the extension flume, 72 individuals (305–1015 mm long) were implanted with radio-transmitters and released into the fish lock exit channel. In 2004 (power station inflows 10 300 ML day–1), the majority of fish exited successfully (44 of 45) and only a single fish (2%) was entrained into the power station. In 2005 (power station inflows 12 000 ML day–1), fish again exited successfully (26 of 27) but with a higher proportion entrained (5 of 27; 18%). This reduced success appeared to be related to strong transverse flows with high water velocities adjacent to the fish lock exit. The efficiency of fish passage at this site might be improved by altering water management strategies, integrating engineering and fish biology, and through field-testing of proposed solutions.

Sign in / Sign up

Export Citation Format

Share Document