Tunnel axial difference deformation design value determination method based on surrounding rock spatial variability

Abstract

The invention discloses a tunnel axial difference deformation design value determination method based on surrounding rock space variability. The method comprises the following steps: obtaining a random distribution function of surrounding rock mechanical parameters; dividing finite element model units according to the characteristics, determining the number of types of different mechanical parameter units, and performing assignment on each unit by adopting a random sampling method to obtain a finite element model of space variation distribution of the surrounding rock; obtaining the displacement value of any point of the surrounding rock through each assignment; obtaining a displacement statistical rule considering random distribution of surrounding rock space through multiple times of calculation; calling the difference value between the displacement value w1 corresponding to the cumulative probability P1 and the displacement value w2 corresponding to the cumulative probability P2 as a tunnel difference deformation probability design value; changing the value of the mechanical parameter standard deviation, obtaining a displacement statistical rule under a plurality of standard deviation working conditions through multiple times of assignment, obtaining a probability design value of tunnel differential deformation, obtaining a probability design value-standard deviation function of surrounding rock space random distribution tunnel differential deformation, and providing a theoretical basis for realizing tunnel reliability design.

Description

technical field [0001] The invention relates to a method for determining the design value of tunnel axial differential deformation based on the spatial variability of surrounding rock, and belongs to the technical field of underground engineering construction. Background technique [0002] After the excavation of the actual deep tunnel, the damage and plastic distribution in the surrounding rock are usually related to the distance of the excavation face; considering the spatial variability of the initial state of the surrounding rock, the mechanical parameters at different depths of the actual surrounding rock have obvious spatial differences. variability. However, the traditional design and calculation method of tunnel wall displacement is to select the average value of the elastic modulus or the definite value of a certain typical section as the design parameter, and use the modified Fenner formula to directly calculate. The error is very large, and it is impossible to pre...

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Problems solved by technology

However, the traditional design and calculation method of tunnel wall displacement is to select the average value of the elastic modulus or the definite value of a typical section as the design parameter, and use the modified Fenner formula to directly calculate it. The error is very large, and it is impossible to predict a certain line along the longitudinal direction. Differential deformation value of rock mass

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