Abstract

The coefficient of tunnel broken zone combined with the max thickness is used to descript the loosening zone distribution after excavation, which defined to the ratio of broken zone area to tunnel cross section. With 16 operation modes designed by Orthogonal test, coefficient of the broken zone can be obtained with numerical methods. The findings suggest that the order of each factor is: surrounding rock grades, ratio of depth to span, side pressure coefficient, buried depth, span length. Gonghe tunnel of Yu-Xiang highway is used to introduce the basic flow of tunnel broken zone coefficient test. Results show that the broken zone coefficient is closely related to geological conditions and excavation methods and the scope of broken zone can effectively reduce by selecting suitable ratio of depth to span and excavation method.

Keywords:

Broken zone, excavation, field test, numerical methods, orthogonal test,

References

Competing interests

The authors have no competing interests.

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The authors have no competing interests.