Large-section underground space non-excavation construction prestress bunching structure and construction method

Abstract

The invention discloses a large-section underground space non-excavation construction prestress bunching structure and a construction method. The large-section underground space non-excavation construction prestress bunching structure comprises a plurality of corner pipes, a plurality of square steel pipes and a plurality of post-tensioning method prestress bunches, wherein a tubular structure is defined by the multiple corner pipes and the multiple square steel pipes, each corner pipe is arranged at the corner position of the cross section of the tubular structure, the plurality of square steel pipes corresponding to each straight side of the cross section of the tubular structure and the corresponding two corner pipes are anchored and fixed through post-tensioned prestressing tendons, and the space between each square steel pipe and the adjacent square steel pipe or the space between each square steel pipe and the corner pipe is filled with concrete for sealing. During construction, 1, the corner pipe with the highest elevation serves as a starting point, jacking is conducted in batches, and the tubular structure is formed; 2, a corrugated pipe and a middle rib plate are arranged; 3, steel strands are threaded and concrete filling is carried out; 4, all the steel strands are tensioned; and 5, a soil body inside the tubular structure is excavated, wherein the cracking or stripping part of the concrete is sealed by polyurethane. The prestress bunching structure and the construction method are more suitable for large-section underground space, standardization can be better implemented, and therefore, the construction efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of underground space construction, in particular to a prestressed bundled structure and a construction method for non-excavation construction of a large-section underground space. [0002] Through the double-row steel strands and the middle rib of the standard pipe, the filling of concrete in the pipe is solved and the material is saved. There is also quick install. In addition, the large span can flexibly arrange the internal structure. Background technique [0003] With the continuous acceleration of the urban process, the underground space gradually shows a deeper and larger development trend, and the conventional open-cut method gradually shows more and more problems of safety and quality, cost and construction period, conservation and environmental protection. Therefore, underground excavation technology has become an unavoidable way of thinking in underground space construction. As we all know, the ...

AI Technical Summary

Problems solved by technology

However, what restricts its application the most is that when the span is large, the method of revealing cannot meet the corresponding force requirements, so it cannot meet the structural form of the large-section underground space.

In addition, there are still the following problems: First, the form and layout of tensioning prestressed tendons need to be calculated according to the simplified model, combined with the distribution of positive and negative bending moments, and a prestressed tendon is bent from the negative bending moment area to the positive bending moment area. area, so as to ensure that the prestressed tendon is located in the tension area of ​​the section, which belongs to the flexural prestressed member in the design principle of concrete structure

Inevitably, first, the distribution of positive and negative bending moments is calculated by a simplified beam model, and the reliability of simulating the actual situation in which discrete concrete steel pipes are stretched to form a whole needs further research; are completely equal, but a prestressed tendon provides the same tensile force, which will affect the stress state of each section, so that the distribution of positive and negative bending moments is more difficult to determine; third, due to the bending of the prestressed tendon, part of the prestressed force is close to the section In the middle, except for the “zero point” section of the bending moment, there is a tension zone in the other sections, which may cause more serious opening and leakage between pipe sections

Secondly, according to the design of the bending prestressed member, the square steel pipe at the corner needs to be equipped with a diaphragm and filled with a part of concrete, so as to ensure the mechanical performance of a part of the negative moment area at the corner, but the setting of the diaphragm reduces the internal labor of the square steel pipe. Therefore, the corner square steel pipe needs to be enlarged and adopts a special-shaped section, and each steel pipe needs to be filled with concrete, resulting in a lot of waste

Thirdly, the adopted "C-T" slot or "double L" slot resulted in the inability of the flanges of the steel pipes on all sides to be closed to form a continuous force, thereby greatly reducing the calculated height of the section and causing unnecessary waste

Finally, the bent prestressed tendons need to leave holes at different positions on the outer walls of the steel pipes on all sides, so that each steel pipe needs to be further drilled and processed in the project, with low standardization and cumbersome procedures

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