Full-section precast concrete pouring method

Abstract

The invention relates to the technical field of immersed tube tunnels. The invention relates to a full-section precast concrete pouring method. A single immersed tube section is divided into a bottompouring section, a wall pouring section and a top pouring section; after bottom pouring is completed, wall pouring is conducted; top pouring is conducted after wall pouring is completed; every two ofthe bottom pouring, the wall body pouring and the top pouring are continuous; the bottom pouring, the wall pouring and the top pouring are continuously carried out in sequence to complete full-sectionprecast concrete pouring of the immersed tube sections. The immersed tube sections prepared by the method are free of layering so that the problem that cracks are generated at layering positions is completely eradicated from the source. By means of bottom pouring, the lateral acting force and buoyancy, generated in the mode that concrete is directly poured from top to bottom, on the formwork arereduced, traditional layered pouring is replaced with full-section pouring, the problem that cracks are generated in a layered mode is solved, and the full-section precast concrete pouring operation process is standardized.

Description

technical field [0001] The invention relates to the technical field of immersed tube tunnels, in particular to a full-section prefabricated concrete pouring method. Background technique [0002] Crack control is a key factor that needs to be considered in the construction process of mass concrete. As a typical mass concrete structure, immersed tube tunnel concrete has a large structural volume (more than 25m in cross-section width and more than 6m in height) and complex cross-section, which leads to self-constrained structures. Large, under the action of temperature deformation, concrete is prone to cracks; moreover, the immersed tube tunnel has been buried in water during its use, and under long-term water pressure conditions, the cracks generated are easy to connect and extend, becoming water seepage channels, causing its The self-impermeability is reduced and erosion is accelerated; at the same time, the immersed tube concrete structure is buried underwater for a long tim...

AI Technical Summary

Problems solved by technology

[0003] Due to the large temperature field and stress field involved in mass concrete, there are great requirements on the pouring process control and formwork system. In order to effectively control the temperature field and stress field, in the existing technology, precast concrete is mainly poured in layers and sections. , but the immersed tube poured by this process will produce cracks at the layered connection after long-term use. Since the immersed tube is buried underwater, it is difficult to maintain the cracks. According to statistics: a 280-meter-long immersed tube tunnel maintains cracks The 50-year maintenance cost is about 5-10 million, and the maintenance cost of precast concrete pouring in layers and sections is large

[0004] In order to solve the above problems, full-section pouring has been gradually developed, but the existing full-section precast concrete pouring technology is extremely immature, and it faces a series of pouring process problems such as how to control the pouring sequence, pouring speed and pouring volume. One-time pouring from top to bottom will increase the force of concrete on the formwork and formwork support

[0005] Therefore, there is an urgent need for a good one-time full-section pouring, which can solve the problem of cracks caused by layered pouring.

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