Study on The Influence of Phyllite Anisotropy Characteristics of Phyllite on The Surrounding Rock of Power Transmission Tunnel

In order to study the influence of creep characteristics of soft rocks, mainly Phyllite, on the long-term stability of transmission tunnel projects in high mountainous areas, this paper designs triaxial creep tests by considering the creep anisotropy of laminated Phyllite to study the anisotropy of creep parameters of different produced laminated Phyllite and the influence of creep anisotropy characteristics of Phyllite on the large deformation of tunnel surrounding rocks. It is shown that the typical damage modes of Phyllite at different dip angles of the rock formation under different circumferential pressures (0MPa, 3MPa, 6MPa) can be roughly categorized into four types: tensile damage, shear slip damage along the lamellar surface, compression-shear tensile damage, and tensile shear damage. The creep parameters such as E1, E2, η1, η2, etc. obtained by using Burgers creep model have obvious anisotropy and inclination effect. It is verified by numerical simulation that the improved Burgers model can better reflect the real situation. This study is of great practical value for optimizing the support process of power transmission tunnels under different inclination conditions in actual projects.