Method for excavating combined vertical erection branch part of super-large rocky section tunnel steel frame rock wall

Abstract

The invention provides a method for excavating a combined vertical erection branch part of a super-large rocky section tunnel steel frame rock wall. The method includes the specific steps that an excavation section of a tunnel is set, wherein an upper left pilot tunnel is a first excavation part, an upper right pilot tunnel is a second excavation part, the upper left pilot tunnel and the upper right pilot tunnel constitute an upper excavation section, a lower left pilot tunnel is a third excavation part, a lower right pilot tunnel is a fourth excavation part, a rock wall body is a fifth excavation part, the lower left pilot tunnel, the lower right pilot tunnel and the rock wall constitute a lower excavation part, and besides, a first supporting and protecting part, a second supporting andprotecting part, a third supporting and protecting part, a fourth supporting and protecting part and a fifth supporting and protecting part are included; the various excavation parts are excavated inturn, and primary support and protection is conducted on the corresponding supporting and protecting parts; in the entire excavation process, the second excavation part is kept lagging behind the first excavation part, the third excavation part lags behind the second excavation part, and the fourth excavation part lags behind the third excavation part. According to the method, large-scale machinery is convenient to work in the case of a super-large section tunnel, the excavation speed is fast, and the economic benefit is obvious.

Description

technical field [0001] The invention relates to the excavation field of rock super-large-section blasting method in tunnels and underground structures, in particular to a partial excavation method for rock super-large-section tunnel steel frame rock wall composite vertical braces. Background technique [0002] According to data, with the further development of my country's transportation industry, a large number of large-section tunnel projects have emerged. At present, in the construction of shallow large-section tunnels, step-by-step construction methods such as step method, CD method, CRD method and double-side pilot-pit method are mainly used at home and abroad. The main idea is to turn the large section into a small section and reduce the span of a single excavation of the tunnel, which is conducive to the stability and safety of the construction along the road. [0003] 1) Step method and step division method. Due to the influence of traditional construction methods, ...

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Problems solved by technology

[0007] There are some problems in the above methods, such as complex construction procedures, multiple disturbances to the surrounding rock and difficulty in switching between various construction methods, long construction period, high cost, poor construction quality, etc.

[0008] In grade IV surrounding rock, grade III shallow buried and partial pressure sections, etc., the CD method is often designed for excavation, which has the characteristics of slow demolition of the temporary support system, long construction period, and high cost.

If the step method of middle partition is used for construction, the excavation area of ​​the middle partition of the upper step and the lower step will be too large at one time, which will easily cause the instability of the surrounding rock

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