Study on Creep Damage Behaviors and Model of Rock Mass During Excavation and Unloading Under High Seepage Pressure

The dynamic high seepage pressure environment caused by reservoir storage and discharge during the operation of large‐scale power stations is an important factor leading to the deterioration of rock structure and the intensification of creep deformation during excavation unloading of hydraulic bank slopes. Based on the unloaded rock mass caused by segmented excavation of reservoir bank slopes, creep tests were conducted on unloaded samples with the same unloading level under different seepage pressures. The creep mechanical properties, seepage evolution laws, and crack propagation laws and mechanisms of unloaded samples under graded loading conditions were analyzed. The one‐dimensional creep model of the Hausdorff derivative was introduced and extended to a three‐dimensional form. The applicability of the three‐dimensional extension form of the creep model was verified by test data. Through parameter sensitivity analysis, the correlation between derivative order and damage factor with time‐dependent deformation characteristics and creep stages of rock was revealed.