Circular tunnel mechanical calculation method considering interaction between surrounding rock and a supporting structure

Abstract

The invention relates to a circular tunnel mechanical calculation method considering the interaction between surrounding rock and a supporting structure. The method comprises the following steps that1, establishing a circular tunnel mechanical model; 2, selecting a rock strength criterion: selecting a Dryer-Prager (D-P) criterion in place of Mohr-Culomb (M-C) criterion to consider the influence of the middle main stress; Thirdly, analyzing a surrounding rock secondary stress field and a displacement field caused by tunnel excavation on the basis of an elastic-plastic theory; Fourthly, considering the cubic stress field and displacement field of the surrounding rock considering the interaction of the surrounding rock and the supporting structure, wherein the rigidity of the supporting structure and the timing of the supporting structure are used to reflect the surrounding rock support in the calculation of the supporting force of the supporting structure; The interaction of the structure, and then its influence on the plastic zone of the surrounding rock and the stress field and displacement field. The calculation method comprehensively considers the influence of three factors, such as the intermediate principal stress, the stiffness of the supporting structure and the timing of the application, on the displacement and plastic zone of the surrounding rock of the circular tunnel, which makes the calculation result more in line with the actual situation.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering mechanical model research, and specifically relates to a circular tunnel mechanical calculation method considering the interaction between surrounding rock and supporting structures, which is used for the research of various rock and soil underground engineering mechanical models such as tunnels and underground chambers . Background technique [0002] One of the core ideas of the new Austrian method of tunnel construction proposed in the 1960s is to make full use of the self-supporting capacity of the surrounding rock, that is, the lining and the surrounding rock are no longer regarded as the main body of the load and the source of the load, but both are regarded as As a bearing system, the main function of support is to fully mobilize the self-supporting capacity of the surrounding rock. Since then, the theory and practice of tunnel support have also been greatly developed, and the intera...

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Problems solved by technology

For this reason, according to the spatial effect of the excavation surface, that is, the Hoek fitting equation, the distribution curve of the radial displacement of the tunnel roof along the longitudinal section of the tunnel was calculated, and a mechanical model considering the coupling effect of surrounding rock and support structure was established. There are two problems: the first is that it does not consider the influence of the intermediate principal stress, and the second is that it only studies the distribution curve of the radial displacement of the tunnel roof along the longitudinal section of the tunnel, but does not consider the surrounding area in the direction of the tunnel cross section. Rock deformation and plastic zone range

[0005] However, although abundant research results have been obtained on the interaction mechanism between the surrounding rock and the supporting structure of the circular tunnel, there are still some problems, such as failure to fully consider the intermediate principal stress, the stiffness of the supporting structure and the construction The influence of timing and other factors on the displacement and plastic zone of the surrounding rock, thus causing the theoretical calculation results to be inconsistent with reality

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