When excavating a tunnel, the stresses are distributed asymmetrically along the tunnel cross-section. Other factors, particularly slope friction force and excavation speed, can also contribute to the deformation and displacement of a tunnel. Despite this, several authors have used the complex potential method to predict the ground deformation surrounding the tunnel. However, their applicability to the ground response caused by the asymmetric stress distribution around the tunnel wall is analysed in this context. This paper, therefore, proposes an approximate solution on the slope to predict the tunnel cross-section deformation. The solution is based on the complex potential method to predict analytically and numerically the ground deformation around the tunnel. However, two variables called the “complex potential functions” for the Laurent series expansion are used for the stress redistribution to the tunnel boundary conditions. Data from the Qijiazhuang tunnel case are used to justify the proposed analytical solutions. This solution is an essential guide for analyzing deformations in complex geological conditions and structures, such as steeper slopes.

Affected by the bias stress, the mechanical properties of shallow buried bias tunnel construction are complex. The influence of different construction methods on the stability of the portal section of the shallow buried bias tunnel has received significant attention in past studies, but the microscopic mechanism of it has not been properly analyzed. In this study, the discrete element method is used to simulate the construction steps of the three‐step method and the single side heading method with and without systematic bolt supports taking Qijiazhuang tunnel as the research object. The tunnel surrounding rock stress, vertical displacement, and surface deformation results under different working conditions are analyzed, and the mechanism of systematic bolt supports is analyzed from microscopic perspective. The results show that the single side heading method can gradually release the load and deformation and better play the supporting capacity of lining; the existence of systematic bolt improves the shear capacity of surrounding rock and enhances the arching effect, thus significantly reducing the vertical displacement of surrounding rock and surface deformation. Finally, compared with the field monitoring data, it is recommended to adopt the single side heading method with systematic bolt support for the construction of the portal section.