An operation tunnel bolt reinforcement method

Abstract

The invention relates to a bolt reinforcement method for operating tunnels, specifically: fitting the radius r of the loose ring arch part of the surrounding rock based on the finite element forward analysis method 1 or arch radius r in the plastic zone 2 and the mathematical model of the lining parameters and surrounding rock parameters of the tunnel; collect the surrounding rock lithology, lining parameters and surrounding rock parameters of the tunnel, and input the lining parameters and surrounding rock parameters into the mathematical model to solve r 1 or r 2 ; The lithology of the surrounding rock is that the tunnel lining arch and the side wall are loose and broken, and the load is calculated according to the rock self-weight stress in the range of the loose circle; the surrounding rock lithology is expansive. The load is solved by establishing a finite element model with the same parameters as the tunnel lining and surrounding rock through forward analysis; the number N of reinforcement bolts required for the tunnel lining arch and side wall is determined by the load, and based on the determined N pairs of operating tunnels Perform anchor reinforcement. Compared with the prior art, the invention has the advantages of quantitative parameterized design, high precision and the like.

Description

technical field [0001] The invention relates to bolt reinforcement technology, in particular to a bolt reinforcement method for operational tunnels. Background technique [0002] The bearing capacity of the tunnel decreases during the long-term operation, which brings many safety hazards. In order to ensure the safety of operation, the anchor bolt reinforcement technology can be used to improve the bearing capacity of the tunnel and extend the service life of the tunnel. [0003] The existing bolt reinforcement technology is usually carried out during the construction period. With the popularization of high-strength concrete, the tunnel's bearing capacity can also be improved by bolt reinforcement when the tunnel in the operation period has insufficient bearing capacity and service performance degradation. and service life. [0004] The key to implementing bolt reinforcement in operational tunnels is to determine the scope of the surrounding rock loose circle or plastic zon...

AI Technical Summary

Problems solved by technology

The empirical method lacks sufficient theoretical basis; the on-site detection method of the surrounding rock loose circle or plastic zone (expansive surrounding rock) is suitable for the construction period, and drilling and sampling are required, and the detection range is limited, which will also damage the safety of the operating tunnel structure; The back-analysis method requires numerical inversion analysis for each detected deformation data, which requires a large amount of calculation, and does not take into account the voids behind the lining and structural cracks in the operating tunnel, and there are still large differences between the analysis results and the actual situation.

The above problems often lead to small analysis results of the loose circle or plastic zone of the expansive surrounding rock, resulting in a small reinforcement range of bolts, making the structure in an unsafe state

[0005] The existing technology also provides some solutions. Chinese patent CN201711298427.4 discloses a quantitative design method for roadway support based on the size of the plastic zone of surrounding rock, including the following steps: calculating and determining the size of the radius R of the plastic zone of surrounding rock in the roadway; According to the calculation results, the roadway surrounding rocks are classified; according to the classification results of the roadway surrounding rocks, the support parameters are designed for different types of surrounding rocks; according to the site monitoring feedback information, the support parameters are modified and adjusted, and the design is based on the size of the plastic zone. The supporting parameters of the roadway are scientific and reasonable. On the basis of obtaining the radius of the plastic zone of the roadway and the geometric characteristics of the boundary, the surrounding rock of the roadway is classified with the radius of the plastic zone as the main index, so as to carry out targeted support for different types of surrounding rock. Design of protection parameters to ensure the scientific and economical design of roadway support; however, the patent derives the radius of the plastic zone of the surrounding rock based on the formula, which will be affected by the constitutive relationship of rock and soil, resulting in a large amount of calculation and inaccurate results

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