Once-closure and staging-closure combined dam type power plant construction diversion method

Abstract

The invention relates to a once-closure and staging-closure combined dam type power plant construction diversion method and aims to reduce technical difficulty and risk, control construction flood season water level, reduce engineering cost and shorten generation period. The technical scheme includes steps of a, respectively building an entrance cofferdam and an exit cofferdam at the entrance and the exit of a diversion tunnel to be built on the first bank of a riverway; b, constructing the diversion tunnel, and excavating part of a first-stage foundation pit on the dry land on the first bank of the riverway; c, dismantling the entrance cofferdam and the exit cofferdam; d, constructing an upstream dry-season sub-cofferdam and a downstream dry-season sub-cofferdam of a once-closure riverbed on the riverway; e, constructing a longitudinal annual water-retaining cofferdam distributed along the riverway in the first-stage foundation pit close to the bank of the riverway by means of a dry season, and planning to excavate the second-stage foundation pit on the other side of the longitudinal annular water-retaining cofferdam; f, constructing behind-dam power generation plant in the dry season and the flood period in the first-stage foundation pit, and constructing a dam flood-discharge section in the second-stage foundation pit in the dry season.

Description

technical field [0001] The invention relates to a construction diversion method for a dam-type hydropower station which combines one-time interception and stage-by-stage interception. It is applicable to the layout design and construction of hydraulic junctions with indistinct wide and narrow channels. Background technique [0002] According to the "Code for Construction Organization Design of Hydropower Projects" and conventional design ideas, two construction diversion methods can be used in the layout design and construction of hydraulic junctions of dam-type hydropower stations. [0003] The first method: if the geological conditions are good and the river channel is narrow, tunnel diversion or open channel diversion on the bank can be used, that is, the construction diversion method of constructing a hydraulic hub project in the entire section after blocking the river channel at one time. Its outstanding advantages The layout of the hydraulic project is not restricted ...

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Problems solved by technology

[0003] The first method: if the geological conditions are good and the river is narrow, tunnel diversion or open channel diversion on the bank can be used, that is, the construction diversion method of constructing the entire section of the hydraulic engineering project after blocking the river at one time. Its outstanding advantages The layout of hydraulic projects is not restricted by the construction diversion method; on the one hand, the disadvantages are that the power generation period is usually longer and the project cost is also relatively high; on the other hand, the flood water level during the construction period is relatively high, which affects the resettlement control water level and construction progress

[0004] The second method: if the river course is wide, the staged diversion method can be adopted, that is, after the river course is blocked in stages, the hydraulic hub project will be built stage by stage. Its outstanding advantage is that the control of the flood water level during the construction period is relatively flexible; The layout of the hub project is restricted by the way of construction diversion, so there is little room for adjustment, and the adaptability of the longitudinal cofferdam to unknown geological conditions is poor, so there is a certain risk

[0005] If the width and narrowness of the river channel are not obvious, or because of poor geological conditions, the flood water level during the construction period is restricted by the resettlement control water level, or the project cost and power generation schedule control, etc., the above two construction diversion methods should be adopted When none of them can achieve satisfactory results, how to conveniently carry out the layout design and construction of the hydraulic junction of the dam-type hydropower station, and reduce the difficulty and risk of construction technology, project cost and power generation period are issues worthy of deep consideration

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