This study investigates the creep damage characteristics of weakly cemented soft rock induced by excavation and unloading in an underground chamber

focusing on samples from the western mining area. A series of multi-stage unloading confining pressure creep tests on weakly cemented soft rock was conducted using GDS HPTAS. Under different water conditions

the creep characteristics and creep rate characteristics of weakly cemented soft rock were studied under confining pressure unloading. Based on the reciprocal steady creep rate method

the mathematical exponential function relationship between long-term strength and water content of weakly cemented soft rock was determined. By introducing the Riemann-Liouville fractional order integral operator and the negative time exponential damage evolution variable

nonlinear damage Abel clay pot was defined

and a six-element fractional order creep damage constitutive model

including elastic elements

viscoelastic damage elements

viscous damage elements and nonlinear viscoplastic damage elements

was established. Based on the experimental results

the Trust-Region algorithm in Matlab was used to identify the model parameters and analyze the sensitivity. The results show that the established model has clear physical significance and high agreement with the test values. It can accurately reflect the creep damage characteristics of weakly cemented soft rock under excavation and unloading confining pressure in underground engineering

which is significant for ensuring the long-term stability of underground engineering.