Novel key groove for back-upper heightening of stone-laying gravity dam

Abstract

The invention provides a stone-laying gravity dam of a back-upper heightening and relates to a novel key groove in a hydro-structure. The stone-laying gravity dam of a back-upper heightening is characterized in that before being heightened, the original water-retaining dam sections are heightened, a plurality of shear keys are buried in the orginal water-retaining dam sections, wherein one parts of shear keys are buried in the original water-retaining dam sections, and the other parts of shear keys are exposed, and then the dam is heightened. When the dam is heightened, a backfill cavity is formed between the original water-retaining dam sections and the heightened parts thereof so that the exposed parts of the shear keys drop in the backfill cavity, and finally micro-expansive concrete is filled in the backfill cavity finally. The novel key groove overcomes the adverse influences caused by the initial hydration heat of concrete as well as the defect of the difficult process of digging steps on original dams so that the dams are convenient to rapidly construct, and simultaneously also improves the temperature stress of newly cast large-size concrete so that the joint surface between a new dam body and an old dam body has stronger shearing resistance.

Description

【Technical field】 [0001] The invention relates to a novel reinforced keyway used in raising the height of a masonry gravity dam in a water conservancy project. 【Background technique】 [0002] There are many reasons for the heightening of the masonry gravity dam, such as the high cost of the original design and insufficient funds, so the heightening is done in stages to save the investment in the first phase of the project and make the project more effective in advance. Due to the increasing power load, the dam had to be heightened and the unit output increased to meet various requirements. However, the siltation of the reservoir is serious, and the storage capacity needs to be expanded so that the reservoir can continue to play its role and the hub will not be scrapped. The old dam should be raised to meet this requirement. Some dams lack sufficient data during design, resulting in insufficient dam height and storage capacity, which cannot meet the requirements of flood con...

AI Technical Summary

Problems solved by technology

[0004] However, there are the following problems in the method of integral heightening of the rear foundation: due to the effect of concrete temperature stress, the new concrete poured on the downstream side of the old dam will shrink when it is cooled to a stable temperature, and this shrinkage is affected by the old dam and bedrock. As a result, the new concrete along the joint surface of the old dam body will generate tensile stress

Because it is required not to cause damage to the old dam, the above demolition methods are all done manually, and all loose rocks will be removed. The construction is obviously time-consuming and laborious.

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