Reverse tunnel-out construction method for shallowly-buried broken surrounding rock tunnel

Abstract

The invention discloses a shallow-buried broken surrounding rock tunnel reverse out-of-hole construction method which comprises the following steps: S1, when small-section tunnel construction is close to cut-through, constructing a pipe shed working room in a tunnel hole; s2, backfilling and compacting the intersection area of the pipe shed working chamber and the tunnel face to serve as a climbing channel for upper step construction; s3, guide wall construction of the advanced pipe shed is conducted through the backfill compaction area, and after guide wall construction is completed, advanced pipe shed construction is conducted through a pipe shed drilling machine; s4, after construction of the advanced pipe shed is completed, pre-reinforcement construction is conducted on the upper step tunnel face through glass fiber ribs; s5, after the tunnel face of the upper step is pre-reinforced, the upper step is excavated, one steel frame is arranged every cycle footage of the upper step, a temporary inverted arch is arranged, and one frame is excavated and closed; and S6, after the upper step is excavated to be through, the lower step is excavated, and after the lower step is constructed to be through, secondary lining construction of the tunnel is conducted. The construction safety and the construction quality can be effectively guaranteed.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a tunnel reverse exit construction method for shallow buried broken surrounding rock. Background technique [0002] At present, tunnel projects are built in mountainous areas with complex terrain or in urban areas with many surrounding buildings. Due to factors such as terrain and land acquisition and demolition, tunnel construction often cannot meet the conditions for two-way excavation, or requires a large economic cost to realize two-way excavation construction. . Therefore, under the construction condition of no two-way excavation, the tunnel cannot be penetrated at the position where the surrounding rock is better buried and deep, and can only be achieved by unidirectional excavation and reverse exit. [0003] The traditional construction method of reverse tunnel exit is mainly based on the advanced small conduit grouting pre-reinforcement and circular excavatio...

AI Technical Summary

Problems solved by technology

However, in areas close to penetration, tunnels often have shallow burial depths and poor surrounding rock. The support rigidity of the traditional construction method is often insufficient, and the core soil reserved for the tunnel face will result in limited construction space. The construction quality of the lock foot bolt is difficult to control, which will lead to a large amount of tunnel settlement and deformation, which may easily lead to primary branch invasion or landslides; therefore, the traditional reverse hole method has high construction risks and is difficult to control safety

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