Unsymmetrically loading tunnel construction method

Abstract

The invention discloses an unsymmetrically loading tunnel construction method. The method comprises the steps of 1, determining basic mechanical parameters of surrounding rocks; 2, determining a supporting scheme of arch parts of a tunnel and a supporting scheme of side walls of the tunnel; 3, determining an initial supporting structure of the tunnel; 4, conducting tunnel excavation and initial supporting construction on the tunnel; 5, conducting secondary lining construction on the tunnel; 6, conducting construction on the next section: executing the steps 1-5 again, and conducting construction on the next section; repeatedly executing the step 6 until the entire construction process of the unsymmetrically loading tunnel is completed. The method has the advantages of being simple in process, convenient to implement and good in use effect. The supporting structure adopted for a tunnel anchorage supporting system is designed according to the judgment of instability of the side walls ofthe tunnel, deformation and destruction of the surrounding rocks of the side walls of the unsymmetrically loading tunnel can be effectively controlled, a tunnel arch part supporting system is determined according to the height of the roof caving arch camber when the side wall of the tunnel is in a stable state, requirements of stable supporting of the tunnel are satisfied, and construction costs are low.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a bias tunnel construction method. Background technique [0002] In recent years, with the rapid development of my country's transportation industry, a large number of deep-buried mountain tunnels will pass through water-rich and high-in-situ stress areas. Improper construction will easily lead to the reduction of the tunnel section and the instability of the supporting structure, which will seriously affect the rapid construction of the tunnel and the safe operation in the future. For a long time, many experts and scholars have carried out in-depth research on the deformation mechanism and support technology of soft rock tunnels (also known as weak surrounding rock tunnels). He Benguo et al. took the Muzhailing high geostress tunnel as the engineering background, analyzed the deformation characteristics, energy accumulation, mechanical response and plasti...

AI Technical Summary

Problems solved by technology

[0004] Although many research results have been obtained in the deformation of surrounding rock and support technology of soft rock tunnels, and the research on the collapse and floor heaving of soft rock tunnels is also relatively in-depth, but the research on the common tunnel spall disasters in soft rock tunnels is still incomplete. Rarely, on-site treatment measures for slabs still rely on construction experience, and the treatment effect is not ideal

Especially for soft rock tunnels with unstable side walls, there is almost no construction experience for reference

Moreover, when the soft rock tunnel being constructed is a biased tunnel, due to terrain asymmetry or geological stratum factors, the loads on both sides of the tunnel structure are asymmetrical, resulting in biased pressure, and the surrounding rock instability states of the side walls of the tunnel on both sides are inconsistent. Wall stability control construction is more difficult

[0005] In addition, practice has shown that the basic theory of Platts' caving arch reflects the objective law of ground pressure to a certain extent, but there are still the following deficiencies in soft rock engineering: First, there is a lack of stability conditions for tunnel side walls (also called tunnel sides) Research: Studies have shown that the stability of the tunnel side wall is closely related to the strength of the rock mass itself, the depth of the tunnel, and the excavation height of the tunnel. When the lithology of the tunnel side wall and the tunnel depth are constant, the greater the tunnel height The worse its stability is; Research: When the tunnel side wall is unstable, the side wall will undergo shear failure, such as pull cracking-slip shear failure and single-slope shear failure

Therefore, when applying the basic theory of Platts' caving arch to calculate the caving arch sagittal height and determine the surrounding rock pressure, there are often deviations, which directly affect the accuracy of tunnel support parameters determination.

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