Evolution Characteristics of Multi-Source Mechanical Responses in Soft-Hard Interbedded Tunnel Surrounding Rock with Different Bedding Dip Angles

DOI: https://doi.org/10.62517/jcte.202606305

Author(s)

Xiaohui Wang*

Affiliation(s)

Xi'an-Chengdu Passenger Dedicated Line Shaanxi Co., Ltd., Xi'an, China *Corresponding Author

Abstract

To clarify how bedding orientation affects the excavation stability of tunnels constructed in soft-hard interbedded rock masses, a series of three-dimensional numerical models with different bedding dip angles were developed using 3DEC. The excavation-induced response of the surrounding rock was evaluated by jointly examining the vertical displacement field, vertical stress redistribution, and plastic-zone development. The results show that the vertical displacement field, vertical stress field, and plastic zone are approximately symmetric at bedding dip angles of 0° and 90°. By contrast, pronounced asymmetric responses occur at dip angles of 30°~60°, with the zones of large vertical displacement, vertical stress concentration, and plastic deformation migrating preferentially along the bedding direction. As the bedding dip angle increases, the vertical deformation of the surrounding rock decreases overall, accompanied by a progressive reduction in the peak vertical stress. Plastic failure is predominantly initiated and propagated along the bedding interfaces, indicating that both the failure path and the associated instability mode are strongly governed by bedding orientation.

Keywords

Tunnel; Soft-Hard Interbedded Surrounding Rock; Bedding Dip Angle; Numerical Simulation; Evolution Characteristics of Multi-Source Mechanical Responses.

References

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