Surrounding rock stability evaluation method for tunnel down-traversing goaf

Abstract

The invention belongs to the technical field of tunnel construction, and particularly provides a surrounding rock stability evaluation method for a tunnel down-traversing goaf. The method comprises the following steps that: according to different heights between a tunnel vault and the goaf, selecting a plurality of typical fracture surfaces and conventional fracture surfaces with the same lithology, and utilizing a point load meter to measure the uniaxial compressive strength of a field rock mass; adopting a reinforcement stress meter, a pressure box and a concrete stress meter to collect archaxial force, surrounding rock contact pressure and concrete spray layer radial stress; collecting arch apex displacement; and calculating a dimensionless parameter index value for reflecting tunnel down-traversing goaf arch apex surrounding rock stability, distributing a weight coefficient according to a ratio, establishing the quantitative evaluation value of the tunnel down-traversing goaf archapex surrounding rock stability, and guiding field supporting and construction. By use of the method, testing under a situation of different field rock mass strengths is reinforced, so that the method is more reasonable when surrounding rock stability evaluation relates to field rock mass strength, the evaluation of a surrounding rock control effect can be carried out in the construction field, an indoor test does not need to be carried out, and construction efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a method for evaluating the stability of surrounding rock in a goaf under a tunnel. Background technique [0002] With the rapid development of my country's economy, the demand for transportation has increased sharply, and expressways and high-speed railways have grown rapidly. The role of tunnels in corresponding projects has become increasingly important. In Shanxi, Inner Mongolia and other major coal-producing provinces in Northwest China, many tunnels pass through goafs. area, especially the goaf undercutting is the most common. Due to the complex distribution of coal-measure strata and irregular mined-out areas in my country, such situations are extremely harmful to the safety of tunnel construction. Therefore, it is of great significance to carry out the stability evaluation of the surrounding rock of the tunnel passing through the mined-out area and ...

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a method for evaluating the stability of the surrounding rock of the tunnel under the goaf to at least solve the problem that the evaluation of the stability of the surrounding rock of the tunnel under the goaf is mainly based on single factors and qualitative factors. The force monitoring of the body protection is insufficient, and there is no effective test for the change of the rock mass strength after the tunnel passes through the goaf on site. These factors lead to inaccurate and unreasonable evaluation of the stability of the surrounding rock.

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