Super-large-cross-section tunnel-based surrounding rock classification method

Abstract

The invention discloses a super-large-cross-section tunnel-based surrounding rock classification method. The super-large-cross-section tunnel-based surrounding rock classification method comprises the following steps of (1) obtaining a tunnel excavation section area S; (2) calculating and determining the number of excavation faces according to a formula S / 50, and ensuring the excavation faces to be same in area, wherein S is the tunnel excavation section area in the step (1); (3) performing finite element numerical simulation analysis on practical engineering, and performing strength reduction on the excavation faces and expanded regions of the excavation faces to obtain different safety coefficients a1, a2, a3 and a4; (4) determining weight values b1, b2, b3 and b4 according to the reciprocals of the different safety coefficients a1, a2, a3 and a4 in the step (3); (5) performing zoning on the excavation faces on site; (6) calculating [BQ] of zones, and performing weighting according to [BQ] so as to obtain [BQ]A; and (7) finishing excavation face sketches according to an actual situation, and marking [BQ] and [BQ]A of the zones.

Description

technical field [0001] The invention relates to the technical field of surrounding rock classification, in particular to a surrounding rock classification method based on super-large-section tunnels. Background technique [0002] Surrounding rock classification is to divide the infinite rock mass sequence into finite categories with different degrees of stability according to the rock mass integrity and rock strength and other indicators. [0003] At present, the surrounding rock classification of highway tunnels in my country uses a combination of qualitative feature division and quantitative index division for comprehensive evaluation. The basic indicators of surrounding rock are rock hardness and rock mass integrity. The top two of integrity are expressed by the rock mass integrity coefficient Kv. When Kv has no actual measured value on site, it can be determined according to the rock mass volume joint number Jv. Due to the fact that the sections of tunnels in our countr...

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Problems solved by technology

Due to the fact that the sections of tunnels in our country have become larger and larger in recent years, and the surrounding rock conditions are complex, different grades of surrounding rock characteristics may appear on the tunnel face at the same time. Therefore, the surrounding rock classification method used in my country at this stage has been unable to accurately determine the size of large-section tunnels. Surrounding rock grade

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