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Question:

Concrete construction technology of tunnel roof?

The periphery of the tunnel outline has been sealed with steel seal, and can be used as the external formwork when the concrete is poured. The 3 parts of the tunnel are divided into floor, side wall and roof. When pouring, the concrete can only be pumped in the tunnel, the outside of the tunnel is the Pearl River, and the construction can not be carried out outside the tunnel. The roof pouring, only from the bottom to the pump. Question: 1, the roof concrete pouring, how to discharge the air? How to tamper? 2, the tunnel width of 23 meters, you need to do the construction of the seam or after pouring it? Time is pressing, please reply as soon as possible. Good addition score. Thank you。 If you can't see the picture, click this link:

Answer:

The floor concrete is made by the method of subsection pouring, the length of each section is about 16 ~ 24m, and the construction joint is kept between each construction section. After pouring concrete floor, due to the need for roughly 7 days to meet the design requirements of concrete strength, to remove the floor above the first steel purlin and support. During this period of time can be the first construction of steel bars and formwork works, and then the construction of the outer wall of the leveling layer and the wall of the waterproof layer.
Before pumping concrete, the water in the storage hopper is pumped out of the pipeline to achieve the purpose of wetting and cleaning pipes. And then added to the cement mortar and concrete mix proportion in the hopper (or 1:2 cement mortar), lubricating pipe can start pumping concrete; start pumping, pumping speed slow, hydraulic pressure in the acceptable range, to be pumping well, only with the normal speed of pump. Concrete pumping concrete for continuous operation, if not timely, need to reduce the pump speed, the pump is temporarily interrupted, don't stop stirring; pumping finished cleaning pipes, using air compressor driven cleaning ball, and then immediately wash the concrete pump and pipeline, pipeline disassembled according to different specifications of classification.
Concrete construction technology of tunnel roof:Due to the main roof, the floor of a large amount of concrete pouring, consider the construction period and other factors, the site is equipped with 2 sets of automotive pump or HBT60 pump and 300m Phi pipe and a variety of accessories.

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