Vertical jacking construction method for tunnel inclined shaft entering main tunnel

Abstract

The invention relates to the technical field of construction, and discloses a vertical jacking construction method for a tunnel inclined shaft entering a main tunnel. The method comprises the following steps that step one, a rectangular pilot tunnel is excavated when the inclined shaft is excavated to a certain distance away from the main tunnel; step two, a cuboid support is built in the rectangular pilot tunnel within the range of the main tunnel; step three, an arched support is built; and in the later step, excavation of a vault of the whole main tunnel part is completed through cyclic transposition jacking of two sets of jacks while excavation is conducted, and meanwhile independent supporting for the vault of the main tunnel is formed. According to the vertical jacking excavation method, traditional construction processes such as pilot tunnel climbing are abandoned, another path is found, main horizontal excavation is changed into main vertical excavation, the temporary supporting amount is reduced, and waste is avoided; and after excavation, a surrounding rock area of a three-fork joint section can be reserved, the expanding excavation problem is basically avoided, and large-mass concrete backfilling and large-scale use of complex supporting structures are also avoided.

Description

technical field [0001] The invention relates to the field of construction technology, in particular to a vertical jacking construction method for a tunnel inclined shaft entering a main tunnel. Background technique [0002] Common construction methods for inclined shafts entering main tunnels are as follows: [0003] 1. Straight-line climbing guide tunnel form (such as "big bag method"). The problems of this type of method are: ①The main hole and the secondary hole at the junction of the inclined shaft and the main hole require a large amount of excavation; ②Tunnel expansion The excavation part is concentrated on the vault, and it is inconvenient to pour concrete backfill; ③The excavation part of the tunnel needs to be backfilled with a large amount of concrete, which will generate excess load on the support structure; [0004] 2. Curved climbing guide tunnel form (such as "arc guide pit method"). The disadvantages of this type of method are: ①The curved climbing route incr...

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Problems solved by technology

[0003]1. The form of straight-line climbing guide tunnel (such as "big bag method"). The problems of this kind of method are: ①The main part of the connecting part of the inclined shaft entering the main tunnel Tunnels and sub-holes require a large amount of excavation; ②The excavation part of the tunnel is concentrated on the vault, and it is inconvenient to pour concrete backfill; ③The part of the tunnel expansion needs to be backfilled with a large amount of concrete, which will generate excess load on the support structure ;

[0004]2. Curved climbing guide tunnel form (such as "arc guide pit method"). The disadvantages of this type of method are: ①The curved climbing route increases the surveying and mapping ②The construction work surface at the junction of the pilot tunnel and the main tunnel is narrow, and large tools cannot be used; ③Curved slopes have high requirements for the protection of surrounding rocks, requiring multi-step ascending excavations, and the construction process takes a long time to change. It was sealed by shotcrete in time, and the surrounding rock was severely weathered;

[0005]3. The construction method of turning the small pilot tunnel to the roof. The disadvantages of this method are: ① There is a long turning section after the pilot tunnel enters the main tunnel, and this section consumes A large number of temporary supports (because they need to be removed in the subsequent excavation process); ② The steering position of the pilot tunnel needs to be reasonably arranged to turn to the temporary supports, which requires high technical requirements for the erection and reinforcement of the temporary supports; The large-span excavation surface is generated by the three-dimensional suspended force-bearing area, and the safety is poor;

[0006]4. Similar to the CRD method of expanding the excavation into the main hole, the disadvantages of this method are: ①The cross brace affects the excavation operation, and it is difficult to remove the ballast; ②The construction step There are many and complex procedures, and the construction period is long; ③ Higher technical requirements

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