Tunnel anti-expansion support design method

Abstract

The invention discloses a tunnel anti-expansion support design method. The method comprises the following steps that firstly, the lateral confinement free expansion test and the expansion force and time test are carried out; secondly, according to a test result, parameters of an expansion constitutive equation containing the time effect are obtained; thirdly, according to the expansion constitutive equation containing the time effect, a relation equation of tunnel expansion deformation and support anti-expansion force is established; fourthly, under the boundary condition that the support force is equal to zero, the expansion deformation of the tunnel construction period is worked out, expansion deformation is considered in the reserved deformation design based on the calculation result, and the problems of instability and beyond limit caused by expansibility in the construction period are effectively solved; and fifthly, under the boundary condition of displacement restraint, the expansion force borne by a tunnel running period secondary lining is worked out, the anti-hydrostatic pressure design is added in the secondary lining, the anti-hydrostatic pressure value is not smaller than the maximum expansion force value in the running period, and the problem of stability in the running period is effectively solved.

Description

technical field [0001] The invention relates to a design method for tunnel anti-expansion support. Background technique [0002] In the construction of underground geotechnical engineering, especially for tunnel engineering, the expansibility of expansive rock will generate expansion pressure on the structures, which seriously affects the stability of the project. The harm of expansive rock expansibility to tunnels is mainly reflected in: [0003] 1) During the construction period, the expansion effect will cause the instability and invasion of the primary support. [0004] 2) During the operation period, the expansion force will act on the second lining, causing damage to the second lining and affecting the long-term stability of the tunnel. [0005] The current design methods of anti-expansion support for tunnels are mostly based on engineering experience, and the design parameters given are not economical and reasonable, and there is no systematic, scientific, and accura...

AI Technical Summary

Problems solved by technology

[0003] 1) During the construction period, the expansion effect will cause the instability and invasion of the initial support

[0004] 2) During the operation period, the expansion force will act on the second lining, causing damage to the second lining and affecting the long-term stability of the tunnel

[0005] The current tunnel anti-expansion support design methods are mostly based on engineering experience, the design parameters given are not economical and reasonable, and there is no systematic, scientific, and accurate quantitative design method

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