Phone Number : +8613408630944
WhatsApp : +8613408630944
August 19, 2020
Various sluices, dams, dikes, sea ponds and other hydraulic structures built to intercept water flow, raise water levels, adjust water storage, or prevent river flooding and sea water intrusion. The powerhouses of river-bed hydropower stations, the heads of ship locks in the river, the lock walls and temporary cofferdams are also water-retaining structures. Gates and dams of small height that are only used to raise the water level are also called backwater structures. Many water retaining structures have other functions and are often included in other hydraulic structures. For example, overflow dams, river sluices, and sluice gates are often listed as water discharge structures, and intake gates are often listed as water intake structures.
The safety inspection and evaluation of water retaining structures shall include the following:
1 Review of flood control standards.
2 Seismic review.
3 Structural safety.
4 Seepage stability.
5 Quality analysis.
3.3.2 The review of flood control standards shall include the following:
1 Design flood analysis and calculation.
2 Flood adjustment calculation.
3 Recheck the height of the dam crest.
4 Review of flood discharge capacity.
The seismic review shall include the following contents:
1 Review the design seismic intensity or dynamic peak acceleration.
2 Review the seismic fortification category and the calculation method of seismic effect.
3 Carry out seismic stability analysis of water-retaining buildings, foundations and near-dam reservoir banks where earthquake collapse may occur, calculate the anti-sliding safety factor or anti-sliding structure coefficient, and carry out seismic strength analysis and calculation to determine the possibility of liquefaction of the earth-rock dam And seismic engineering measures.
4 Safety assessment of the quality and operation status of anti-seismic facilities, including dam foundation seepage prevention, weak layer reinforcement, structural integrity and rigidity, construction joint treatment, etc.
5 Review the seismic safety level.
3.3.4 The structural safety assessment of water retaining structures shall include stress, deformation and stability analysis.
3.3.5 The safety evaluation of the water retaining structure shall be carried out in conjunction with the inspection and monitoring data, and the key recheck calculations shall be carried out on the problems or abnormal working conditions that have occurred.
3.3.6 The seepage safety assessment of water retaining structures includes the stability safety assessment of dam body seepage, dam foundation seepage, and seepage around the dam, which should include the following:
1 Check whether the anti-seepage and anti-filtration drainage facilities, design and construction (including foundation treatment) of the project meet the requirements of current relevant regulations.
2 Analyze the abnormal seepage phenomenon occurred in the operation of the project.
3 Analyze the working behavior of the anti-seepage and filter drainage facilities under the current conditions of the project, and predict the safety of seepage in the future high water level operation.
Water-retaining buildings include various types of dams such as gravity dams, arch dams, earth-rock dams (face rockfill dams), buttress dams, sluice dams, rubber dams, and hydraulic automatic control flap dams.
When evaluating the possibility of earth-rock dam liquefaction and seismic engineering measures, it includes the dam foundation and the bank near the dam.
Earth-rock dams should focus on deformation and stability analysis, concrete dams should focus on strength and stability analysis, and deformation and stability analysis should be focussed on near dam banks and joints.
There are many types of water-retaining buildings in hydropower stations, and the structural safety evaluation methods are different. The specific review content and methods should be carried out in accordance with the corresponding design specifications. When there is a lack of monitoring data, calculation and analysis combined with on-site testing can be used for evaluation.
On-site inspection of water-retaining buildings, combined with other methods to further evaluate the safety of hidden dangers in seepage state. The abnormal phenomena that occurred in the project include: under the same conditions, the seepage flow through the dam body, the dam foundation and the bank slopes of the two dams continues to increase; the seepage water appears turbid or suspicious; the water outlet position is raised or moved, etc.: on the earth-rock dam, The downstream dam slope is wet and soft, collapsed, and water is discharged; the dam toe area is severely exposed to water and sand, soft uplift or collapse; vortex leakage occurs in the reservoir, and the cover produces serious pits or cracks; the dam body and the two dam end bank slopes, water pipes ) The wall and other joints are leaking seriously and appear turbid; seepage pressure and seepage flow increase at the same time, or suddenly change its previous relationship with the reservoir water level.