Method for evaluating protection effect of newly-built tunnel grouting ring on existing shield tunnel

Abstract

The invention discloses a method for evaluating the protection effect of a newly-built tunnel grouting ring on an existing shield tunnel. The method comprises steps of a three-dimensional coordinate system and a grouting ring mechanical calculation model being established according to the relative positions of a newly-built tunnel, an existing tunnel and the grouting ring; according to the established grouting ring mechanical model, the influence process on the surrounding soil layer being simulated through volume expansion of the grouting ring, and a formula for solving the additional stressof the surrounding soil layer caused by expansion of the grouting ring being deduced by utilizing a random medium theory; considering the influence of excavation of the newly-built tunnel and volume expansion of the grouting ring, and calculating the total vertical additional stress at the axis of the existing tunnel under the combined action of the excavation and the grouting ring; substituting the total vertical additional stress into the shear slab staggering and rigid body rotation cooperative deformation model to obtain the vertical displacement of the existing tunnel, and evaluating therationality of a tunnel underneath pass scheme and a grouting ring setting scheme according to the obtained vertical displacement of the tunnel. The method can be designed and optimized through repeated adjustment of parameters and multiple times of substitution checking calculation.

Description

technical field [0001] The invention belongs to the technical field of underground engineering, and in particular relates to a method for evaluating the protective effect of a newly-built tunnel grouting ring on an existing shield tunnel, which is suitable for projects in which a grouting ring is installed behind the wall of a newly-built tunnel for reinforcement, especially for shield tunneling at short distances In the existing tunnel engineering, it is especially suitable for analyzing the protective effect of the grouting ring on the existing tunnel. Background technique [0002] With the development of urban subway construction, more and more subway pipelines appear in the limited shallow ground space, and it is inevitable that new shield tunnels will pass through existing tunnels at close range. The short-distance crossing of the shield tunnel will cause deformation of the surrounding soil and redistribution of soil stress, which will affect the structural safety of th...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for evaluating the protection effect of a new tunnel grouting ring on an existing shield tunnel, so as to solve the difficulty in the accuracy of the existing numerical simulation method, measured data analysis method, and scaled-down model experimental method in the calculation process. Problems with control or inability to perform single factor analysis on grouting rings

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