Construction method of shallow buried underground excavating tunnel super large section using PBA method

Abstract

The invention relates to a method of shallow embedment and concealed excavation based on the PBA method for construction on super large cross-section of tunnel, comprising the following steps: 1. to detect the geologic cavity over the wide span tunnel structure; 2. to arrange the ground dewatering well and the tunnel horizontal well; 3. to take the horizontal channels of vertical well as the front large pipe shed on the arch part of the main body and to inject for strengthening the terrain formation; 4. to carry out the supporting arch construction on the side span of small pilot tunnel and the supporting major arch construction on the main body; 5. to excavate the soil mass of lower cross section as the extended foundation and the central partition wall; 6. to remove the bottom central partition wall section by section, construct bottom underlayer and waterproof layer, pour the reinforced concrete; 7. to remove the central partition wall of the upper part section by section and temporary steel shotcrete in the small pilot tunnel, construct the waterproof layer and concrete of the side wall and the main arch. The method of shallow embedment and concealed excavation based on the PBA method for construction on super large cross-section of tunnel has the advantages of guaranteeing the safety, quality and time limit of the construction, saving cost and enhancing work efficiency.

Description

Technical field: [0001] The invention belongs to a building construction method, in particular to a construction method for super-large section of a shallow-buried underground excavation tunnel by using the PBA method. Background technique: [0002] At present, the construction technology level of large-span tunnels in China mainly includes open-cut method and shallow buried method. Among them, the shallow burial and underground excavation methods include the double-side wall pilot pit method and the "PBA" method used in large-span subway stations. However, these methods have different defects and limitations for construction environments with complex surrounding environments, dense underground pipelines, poor geological conditions, abundant groundwater, and large cross-sectional spans. [0003] 1. Open-cut method For the working conditions with a lot of ground traffic and a lot of underground pipelines, pipeline relocation and traffic relief must be carried out during cons...

AI Technical Summary

Problems solved by technology

However, these methods have different defects and limitations for construction environments with complex surrounding environments, dense underground pipelines, poor geological conditions, abundant groundwater, and large cross-sectional spans.

[0003] 1. Open-cut method For the working conditions with a lot of ground traffic and a lot of underground pipelines, pipeline relocation and traffic relief must be carried out during construction, so the construction will be greatly disturbed and the construction period will be long; high, poor economy

[0004] 2. The shallow-buried double-side-wall pilot pit method adopted is extremely unfavorable for the safety control of the pipeline above the structure and the surrounding environment for the construction environment with poor geological conditions, complex surrounding environment, and many underground pipelines, and the construction risk is high. It is difficult to guarantee safety from theoretical analysis

[0005] However, due to its wide application range, the PBA method is suitable for excavation of tunnels with poor strata, poor geological conditions, large spans, and strict ground subsidence requirements, and can reduce ground subsidence and remove temporary support with relatively small workload, simplifying The construction technology and work efficiency are high, so it is applied in the construction of long-span subway stations, but it has not been applied to the construction of long-span tunnels

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