Shallow-buried tunnel pipe-roof underground excavation full-section construction method under complicated environmental conditions

Abstract

The invention provides a shallow-buried tunnel pipe-roof underground excavation full-section construction method under complicated environmental conditions. By combining a pipe-roof underground excavation technology and a shallow-buried underground excavation tunnel construction safety and settlement control technology, one or more of the following measures is taken: (1). shortening the distance range of capping mass clearing of each inverted arch, the spatial distance range between the capping mass clearing process and a tunnel excavation face, and the spatial distance range between a secondlining and the tunnel excavation face to the greatest extent; (2). simultaneously constructing inverted arches and the second lining of an arch wall, and timely closing the second lining to form a ring; and (3). if necessary, reinforcing the tunnel excavation face under the protection of super-strong pipe-roofs to realize the stability of the tunnel excavation face under the condition of full-section excavation. Due to the full-section excavation and the shortening of each process to the greatest extent, the distance between the second lining and the face is effectively shortened; and the annular and longitudinal stress system formed by the second lining, initial supports, and soil and the pipe roofs in front of the face has a better effect than a "shallow-buried underground excavation method" safety guarantee and ground surface settlement control.

Description

technical field [0001] The invention relates to a tunnel pipe curtain full-section construction method, in particular to a shallow-buried tunnel pipe curtain full-section construction method under complex environmental conditions. Background technique [0002] The East Ring Line of Chongqing Railway Hub is located around the city, and the environmental conditions are very complicated. Many places pass through the expressway, such as the new Baiyangwan double-track tunnel with a 4m clear distance under the cutting of the Chongqing Ring Expressway; Maoyakou and Qiaozibao No. 2 single-track tunnel Parallel 2~3m clear distance under the filling subgrade of Yuyi Expressway; Jinyu single-track tunnel under 7m clear distance under the filling subgrade of Jinyu Avenue; Jinshan double-line tunnel HMDK14+540~+595 section near Jinshan Avenue filling subgrade Pass through the 20m thick waste slag body; pass through the area of ​​Zhaojiaxi Interchange under the 10m clear distance at the ...

AI Technical Summary

Problems solved by technology

However, due to its advanced support, pipe sheds or small conduits are generally used, and the tunnel face is generally excavated in multiple sections. The distance between the second lining and the tunnel face is relatively long. Under shallow buried complex environmental conditions, due to the extremely high requirements for surface settlement control, the traditional It is difficult to meet the requirements of tunnel construction safety and surface subsidence control in the construction process of the shallow buried underground excavation method.

[0007] (3) At present, in the application cases of pipe curtain underground excavation tunnels, there are no special requirements for the timing of the secondary lining, and the role of the secondary lining is basically not considered in the control of surface settlement; the tunnel face basically adopts multi-part excavation, and the secondary The sub-face distance is long, and the long-distance excavation is carried out under the action of the primary support, and the construction safety and the effect of surface settlement control are not good

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