Shield tunnel excavation face instability probability determination method

Abstract

The invention discloses a shield tunnel excavation surface instability probability determination method, which comprises the following steps of: 1, initializing random field parameters including a mean value, a standard deviation, a probability distribution type, a correlation function form and an autocorrelation distance of rock-soil body parameters; 2, dividing a research area into random fieldgrids, and numbering random field units; 3, calculating a covariance matrix, and carrying out Cholesky decomposition on the covariance matrix; 4, constructing a standard Gaussian random field model ofthe rock-soil body parameters for N times; 5, constructing a non-Gaussian random field model of the rock-soil body parameters for N times; 6, calculating the ultimate supporting force of the shield tunnel excavation face; and 7, calculating the instability probability of the tunnel excavation surface. According to the method, the instability probability of the shield tunnel excavation face can beaccurately determined, the method is more comprehensive and reliable compared with a previous deterministic analysis method, and a basis is provided for shield tunnel construction and design.

Description

technical field [0001] The invention relates to a method in the technical field of geotechnical engineering, in particular to a method for determining the instability probability of a shield tunnel excavation face considering heterogeneity of rock and soil mass. Background technique [0002] In the construction of urban rail transit projects, shield method construction has the advantages of fast excavation speed, high degree of mechanization, strong stratum adaptability, and small impact on the environment, and has broad application prospects. The control of the stability of the tunnel excavation face is a key technology in the construction of shield tunneling, and it is also a difficult problem in engineering practice to reasonably determine the support pressure of the excavation face. In recent years, in the construction of urban subway tunnels, the accidents of excavation face instability caused by improper support pressure control are not uncommon. These accidents not o...

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Problems solved by technology

In fact, in the above research, the rock and soil parameters are regarded as random variables, and the soil parameters at each spatial position in the calculation model are considered to be completely related, while the random and structural characteristics of the soil parameters themselves are ignored. There is a certain difference between the stable state of the tunnel excavation face and the actual situation

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