Controlling crack of hyperbolic arch dam with a height of 305 m in Jinping hydropower station is an important problem. To improve the anti-cracking ability and reduce cracking risk of hydraulic concrete, polyvinyl alcohol (PVA) fiber and polypropylene thick fiber were used in hydraulic concrete using four gradations of aggregates. Indoor and productive tests were carried through to comparatively analyze workability, physical and mechanical properties and anti-cracking ability. Workability of fiber reinforced concrete was improved to be in favor of construction. When two kinds of fiber were used in concrete, the anti-cracking ability was greatly enhanced with lower elastic modulus-to-strength ratio and lager ultimate tensile strain. Concrete using PVA fiber had better anti-cracking ability than that of concrete using polypropylene thick fiber. PVA fiber reinforced concrete was applied in Jinping hydropower station. It is proved that PVA fiber reinforced concrete has good properties reaching design requirements of workability, compressive strength, ultimate tensile strain, frost resistance, permeability resistance.
Taking excavation and supporting of surge tank large-scale underground cavern group of Nuozhadu hydropower station as example, the stability of surrounding rock is analyzed systematically, and the best lining scheme is obtained. Through primary supporting calculation, the displacement and the small main stress increases continuously with excavation of cavern; the rock-point safety factor of decreases continuously with excavation of cavern; the displacement, the small main stress and the rock-point safety factor soon changed when the surrounding rock unloaded suddenly, therefore, the surrounding rock must be supported timely. After excavation, the maximum total displacement is 10.57mm, the maximum tensile stress is far less than the tensile strength of surrounding rock, and the minimum safety factor of key point does not satisfy the requirement of standard; the surrounding rock surface will be broken but not large-area damage basis of excavation. The key point’s safety factor changes and the safety factor satisfies the standard requirement only when the elevation of the second lining larger than this key point. According to lining scheme comparison, the scheme that concrete of surge tank pouring to elevation 625.5m is the most economic and reasonable lining scheme for this engineering.
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