Grading method suitable for soft rock tunnel deformation grade under ultrahigh ground stress effect

Abstract

The invention discloses a grading method suitable for a soft rock tunnel deformation grade under an ultrahigh ground stress effect. A judgment basis is provided from five aspects including a surrounding rock grade, ground stress size, underground water development conditions, a strength stress ratio, absolute deformation and relative deformation; weight factors of all evaluation factors are considered on the basis and a surrounding rock deformation degree evaluation index ELD is provided; and the surrounding rock deformation degree can be divided into four conditions including no large deformation, slight large deformation I, middle large deformation II and serious large deformation III based on the surrounding rock deformation degree evaluation index ELD. The grading method can provide a judgment standard for dividing the deformation grade of an extruded phyllite and carbon slate tunnel; and meanwhile, a theoretical basis and method are provided for constructors to comprehensively know the grading of extruded phyllite and carbon slate. The grading method has the advantages of wide applicable range, high testing precision, strong pertinence, simple and reliable grading method and the like, and guarantees are provided for safe construction of tunnel engineering.

Description

technical field [0001] The invention relates to the field of tunnel surrounding rock deformation classification methods, in particular to a classification method suitable for deformation grades of soft rock tunnels under ultra-high ground stress. Background technique [0002] When tunnels pass through high ground stress, strong residual tectonic stress and fault fracture zone, large deformation of surrounding rock is a widely distributed and extremely harmful construction geological disaster. The large deformation of the tunnel is a force deformation and damage phenomenon of the soft surrounding rock under the joint action of ground stress, construction influence, groundwater and other factors. The rock mass loses or partially loses its self-stabilizing ability, and the deformation of the surrounding rock cannot be restrained, resulting in a loose area of ​​the surrounding rock, which in turn destroys the tunnel support system. When large deformation occurs in the tunnel, t...

AI Technical Summary

Problems solved by technology

It can be seen that at present, scholars at home and abroad have their own opinions on the classification of large deformation of surrounding rocks, but there is no consistent criterion for judging whether large deformations occur in surrounding rocks.

In addition, there is no relevant deformation grading standard for extrusive phyllite and carbonaceous slate in China. Most of them only consider how to solve the problems of tunnel support structure and stability, and do not pay attention to in-depth research on extrusive phyllite. The deformation under the influence of different factors has led to a lack of understanding of extrusive phyllite, and it is impossible to take relevant targeted measures

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