Displacement deformation prediction method for shield tunnel with anti-floating anchor rods under foundation pit excavation

Abstract

The invention discloses a displacement deformation prediction method for a shield tunnel with anti-floating anchor rods under foundation pit excavation, and belongs to the technical field of underground engineering. The prediction method specifically comprises the following steps of: predicting; establishing a position relationship between the shield tunnel with the anti-floating anchor rods and aground foundation pit; calculating the additional load of the shield tunnel with the anti-floating anchor rod caused by excavation of the foundation pit; considering a segment ring cooperative deformation model of rotation and slab staggering, calculating the total potential energy Epm of shield tunnel deformation under the action of the anti-floating anchor rod, and solving a longitudinal displacement function w (l), the slab staggering amount delta m2 between adjacent shield segments and the shearing force Qm between adjacent shield segments through Fourier expansion and a variation controlequation. The prediction method has the characteristics that the number of acting segments of the anti-floating anchor rod is considered; the deformation condition of the shield tunnel is close to the real condition; and the accuracy is high.

Description

technical field [0001] The invention belongs to the technical field of underground engineering, and in particular relates to a method for predicting displacement and deformation of a shield tunnel with anti-floating anchor rods under excavation of a foundation pit, which is suitable for shield tunnels with anti-floating anchor rods under the influence of excavation of upper foundation pits The resulting displacement and deformation values ​​are predicted. Background technique [0002] In recent years, with the development of underground engineering construction, urban shallow ground space has become more and more crowded, and the situation that construction projects are adjacent to existing shield tunnels has become more and more frequent. Among them, the excavation of the foundation pit adjacent to the existing tunnel will have an unloading effect on the soil above the existing tunnel, causing the existing tunnel to float and deform, which may cause deformation and damage t...

AI Technical Summary

Problems solved by technology

The main method of existing research is finite element simulation, the results of which have a great relationship with the degree of reduction of the modeling to the real working conditions, and the accuracy of the results cannot be guaranteed. At present, there is no theoretical solution to guide the excavation of foundation pits. Correlative research on the displacement and deformation of the existing tunnel under the anti-floating anchor rod

[0004] In summary, most of the studies on the displacement and deformation of shield tunnels with anti-floating anchor rods under foundation pit excavation focus on finite element numerical simulation, which is difficult to ensure accurate degree, but there is no derivation method for theoretical solutions, and relevant research is urgently needed

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