Abstract: It is known that Jinping-I arch dam is the highest arch dam in the world with a height of 305 m. However, the dam foundation lithology is quite poor due to f5, f8 and other faults exposed on the construction base layer. In addition, the foundation is highly asymmetric. Hence, the evaluation of the ultimate bearing capacity of Jinping-I arch dam cannot reach an agreement due to the geological complexity. Based on the deformation reinforcement theory and 3D nonlinear FEM program T-FINE, the concrete elastic modulus and dam foundation deformation modulus during impounding period are inverted using a direct method and values of the forward inverted plumb monitoring stations. Moreover, the validity and feasibility of the inversion parameters are verified in the impoundment period prediction and the ultimate bearing capacity analysis. The stress and displacement of dam body under normal conditions are simulated with the inversion parameters. Based on project analogy method, the ultimate bearing capacity of Jinping-I arch dam is evaluated completely, considering the yield zones, unbalanced force, plastic complementary energy norm, safety factors and other indexes. The reliability of design parameters is also verified by comparing the calculated results of inversion parameters and design parameters. The results show that K1 (the safety factor when crack initiating) of Jinping–I arch dam is double overload while K3 (the safety factor for ultimate load) is 8 times overload. Hence, it is confirmed that Jinping–I arch dam has a higher ultimate bearing capacity than other arch dams in 300 m height and thus the whole stability is guaranteed.

Key words: Jinping-I, ultimate bearing capacity, parameter inversion, project analogy, unbalanced force