Analysis of Behavior of Edward Hyatt Power Plant

Incremental finite element analyses were conducted to determine whether the measured displacements of the Edward Hyatt (Oroville) Power Plant chamber excavation could be predicted with available procedures. The analyses modeled: (1) Linear rock properties; (2) nonlinear stress-dependent rock properties; and (3) nonlinear stress- dependent rock and joint properties. All three analyses provided reasonable representations of the observed displacements if the material properties were suitably defined, but only the third case, which modeled the joints in a realistic manner, could be used to evaluate the stability of rock blocks around the openings for the design of support systems. A further value of these analyses is to enable the engineer to investigate the effects of different geometries, material properties, and models, even though precisely accurate predictions may not be realized.