Quantification design method for preliminary bracing parameters of unsymmetrical loading tunnel

Abstract

The invention discloses a quantification design method for preliminary bracing parameters of an unsymmetrical loading tunnel. The method comprises the following steps: the preliminary bracing parameters of the unsymmetrical loading tunnel are designed based on shearing resistance damage; the shearing resistance bracing resisting force during tunnel construction is completely borne by a preliminary bracing system; the shear slip force during the unsymmetrical loading tunnel construction is solved according to a limit analysis method; and the shearing resistance bracing resisting force of the preliminary bracing are obtained through stacking the shearing resistance bracing resisting forces provided by an anchor rod, spray concrete, steel frame, etc., which constitute the preliminary bracing system. The invention changes the present situation that at present the design of the preliminary bracing parameters of the unsymmetrical loading tunnel relies on experience for a long time, and realizes the quantification design of the tunnel preliminary bracing parameters.

Description

technical field [0001] The invention relates to a design method of tunnel support parameters, in particular to a quantitative design method of bias tunnel initial support parameters. Background technique [0002] Unbiased pressure tunnel refers to the tunnel in which the surrounding rock pressure is obviously asymmetrical due to various reasons such as terrain, geological structure, construction, etc., so that the support structure bears the unbiased load. Due to the asymmetric distribution of the load acting on the support structure, the force on the support structure is extremely unbalanced, and engineering disasters such as collapse, roof fall, and surface subsidence are prone to occur during tunnel construction. [0003] At present, the design of the parameters of the initial support of unbiased tunnels at home and abroad is mainly carried out on the basis of experience and according to the engineering analogy. Primary support design parameters of surrounding rock. How...

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Problems solved by technology

However, on the one hand, the grade of the surrounding rock of the tunnel is judged by geological engineers based on their personal experience. Different engineers may have certain deviations in the judgment of the grade of surrounding rock. There will also be certain differences in the surrounding rocks of different grades. Using the same design parameters will inevitably lead to risks in construction in some areas, while in other areas it will be conservative

In addition, the design code also proposes to use numerical calculation methods to calculate and analyze the initial support parameters of the tunnel, but it is well known that numerical calculation methods are difficult to accurately simulate the actual effect of the initial support. It is difficult to fully reflect the role played by concrete and steel frames in numerical calculations

Moreover, the load of the eccentric tunnel shows obvious asymmetry, and the corresponding asymmetric design of its support parameters can better exert the support effect of the support system, but the current design method based on experience cannot be based on this Quantify design with asymmetry

[0004] Generally speaking, the design of the parameters of the initial support of the biased tunnel is still based on experience, and it is difficult to ensure the construction safety of the biased tunnel

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