Method for calculating existing shield tunnel displacements caused by new under-crossing tunnels

Abstract

The invention relates to a method for calculating existing shield tunnel displacements caused by new under-crossing tunnels. The method comprises the following steps of: 1, calculating existing tunneladditional stresses caused by a new under-crossing tunnel: a vertical additional stress <sigma>z-q generated by cutter head additional thrust q, a vertical additional stress <sigma>z-f generated by shield shell friction force f, vertical additional stresses <sigma>z-p1 and <sigma>z-p2 generated by slip casting additional pressure p and an additional stress generated by soil mass loss; and 2, calculating longitudinal deformation of the tunnel on the basis of a principle of minimum potential energy: total potential energy of a shield tunnel, a displacement function of an assumed tunnel lining ring and a variation control equation. The method has the beneficial effects that joint effect among tunnel rings is considered, structural characteristics and physical characteristics of tunnels are sufficiently considered, and longitudinal displacements, caused by new under-crossing tunnels, of existing shield tunnels can be rapidly calculated by utilizing Matlab, so that safety of existing tunnel structures under the action of the new under-crossing tunnels can be judged and relatively accord with practical stress and deformation of the shield tunnels.

Description

technical field [0001] The invention relates to a calculation method for calculating the displacement of an existing shield tunnel caused by the underpass of a new tunnel, belonging to the technical field of underground engineering. Background technique [0002] When a new tunnel passes through the lower part of the existing shield tunnel, the original force balance is broken, causing the redistribution of stress in the existing shield tunnel, resulting in excessive lateral or longitudinal deformation, causing segment cracking, joint opening, Bolt failure and other phenomena affect the safety of the subway. Existing calculation methods to analyze the existing shield tunnel under the new tunnel are all based on the elastic foundation beam method, which simplifies the shield tunnel into a homogeneous elastic beam, does not consider the "joint effect" between the tunnel rings, and cannot calculate the segment displacement The amount is different from the actual one. Contents...

AI Technical Summary

Problems solved by technology

[0002] When a new tunnel passes through the lower part of the existing shield tunnel, the original force balance is broken, causing the redistribution of stress in the existing shield tunnel, resulting in excessive lateral or longitudinal deformation, causing segment cracking, joint opening, Bolt failure and other phenomena affect the safety of the subway

Existing calculation methods to analyze the existing shield tunnel under the new tunnel are based on the elastic foundation beam method, which simplifies the shield tunnel into a homogeneous elastic beam, does not consider the "joint effect" between the tunnel rings, and cannot calculate the segment displacement The amount differs from the actual

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