Temperature control and cracking preventing method for construction period of flood discharging tunnel lining concrete

Abstract

The invention discloses a temperature control and cracking preventing method for the construction period of flood discharging tunnel lining concrete, that is, water flowing curing and surface heat preservation of heat preservation material covering are combined. Water flowing curing starts from formwork removing, and the end time takes the standard that the difference of the internal temperature of the flood discharging tunnel concrete and the ambient air temperature is not larger than 10 DEG C; the water temperature is dynamically adjusted and controlled, and determined according to the actually-measured internal temperature of the concrete, and it is appropriate that the difference value between the water temperature and the internal temperature is not larger than 10 DEG C; the water flow gives priority to moisture keeping of the surface of the concrete; and surface heat preservation is conducted after water flowing curing is completed till water passes through a flood discharging tunnel and the flood discharging tunnel operates. By establishing an actual model and combining with concrete engineering, the internal temperature and stress change law of the flood discharging tunnellining concrete under a plurality of temperature control and cracking preventing schemes are calculated and analyzed, it is proved that the temperature control and cracking preventing method for the construction period of the flood discharging tunnel lining concrete meets the temperature control and cracking preventing requirements, the flood discharging tunnel lining concrete can be effectively prevented from being cracked, the cracking preventing effect is remarkable, and important reference value for engineering construction of the flood discharging tunnel is achieved.

Description

technical field [0001] The invention relates to a method for preventing cracking of the lining concrete of a flood discharge tunnel during the construction period. Background technique [0002] With the country's increasing investment in infrastructure and the emphasis on clean energy demand, the rich water resources in Southwest China have gradually been developed and utilized, and many water conservancy projects have been planned and constructed. The geographical environment with many mountains and valleys and the natural climate with large temperature difference between day and night have led to the continuous emergence of various thin-walled concrete structures such as spillway tunnels, aqueducts, tunnels, sluice gates, pumping stations and spillways, especially the construction of spillway tunnels is very common. [0003] The ensuing problem of cracks has to be placed in front of the project builders and relevant scholars. How to scientifically and effectively prevent c...

AI Technical Summary

Problems solved by technology

[0004] At present, the existing methods and standards for temperature control and anti-cracking during the construction period of the lining concrete of the spillway are all formulated with reference to the temperature control methods and measures during the construction period of large-volume concrete buildings such as concrete dams, such as the internal and external temperature difference, the foundation temperature difference and the cooling rate, As everyone knows, for the thin-walled concrete structure lining the spillway tunnel, its thickness is only 0.5-2.0m. For such a thin concrete structure, it is unscientific to use the temperature difference between the inside and outside of the dam concrete, the temperature difference of the foundation and the cooling rate of the 20m thick concrete. Therefore, it still leads to temperature cracks in many spillway tunnel lining concrete during the construction period, and the cracking problem of spillway tunnel lining concrete has not been fundamentally solved.

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