Abstract: On-site experiments are crucial to study rock mechanics due to the complexity and diversity of rock mass. In the past, test conditions restrain the test load setting of rock creep to transient creep, thus it cannot reflect steady-state creep and accelerated creep. The mechanical characteristics of weak rock mass are vital factors which affect the long-term stability of a dam and its underground structure. The creep model which is identified through the two stage characters of transient creep and steady-state creep is presented in the test curve of the bearing plate in dam foundation. Viscoelastic general solutions of deep rock rigid and flexible bearing plate are deduced by applying viscoelastic theory, and uniform expression of Maxwell modal , generalized Kelvin and Burgers model are also given. The rheological parameters obtained through the combination of theoretically analytic inversion and the experiment data form the basis for analyzing long-term stability of dam foundations.

Key words: long-term stability, bearing plate test, compressive creep, rheological parameters, weak rock mass in dam zone