Anchor rod reinforcing method for operation tunnel

Abstract

The invention relates to an anchor rod reinforcing method for an operation tunnel. The anchor rod reinforcing method specifically comprises the steps that a mathematical model of the arch part radiusr<1> of a loose zone of surrounding rock or the arch part radius r<2> of a plastic zone of the surrounding rock and lining parameters and surrounding rock parameters of the tunnel is fitted on the basis of a finite element positive analysis method; surrounding rock lithology, the lining parameters and the surrounding rock parameters of the tunnel are collected, and the lining parameters and the surrounding rock parameters are input into the mathematical model to solve the r<1> or the r<2>; the load capacity of a lining arch part and a side wall of the tunnel with the joint developed or loose and broken surrounding rock lithology is calculated according to the self-weight stress of rock in the loose zone range; the load capacity of the lining arch part and the side wall of the tunnel with the expansive surrounding rock lithology is positively analyzed and solved by establishing a finite element model with the same lining parameters and surrounding rock parameters as the tunnel; and thenumber N of reinforcing anchor rods needed by the tunnel lining arch part and the side wall is determined through the load capacity, and anchor rod reinforcement is carried out on the operation tunnelbased on the determined N. Compared with the prior art, the anchor rod reinforcing method for the operation tunnel has the advantages of quantitative parametric design, high accuracy and the like.

Description

technical field [0001] The invention relates to bolt reinforcement technology, in particular to a bolt reinforcement method for operating tunnels. Background technique [0002] The bearing capacity of the tunnel decreases during the long-term operation, which brings many potential safety hazards. In order to ensure the safety of operation, bolt reinforcement technology can be used to improve the bearing capacity of the tunnel and prolong 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, in the case of insufficient bearing capacity and degradation of service performance of the tunnel during the operation period, the bearing capacity of the tunnel can also be improved by bolt reinforcement. and service life. [0004] The key to implementing bolt reinforcement in operating tunnels is to determine the scope of the surrounding rock loose cir...

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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