Abstract:Firstly the displacement s both f rom field measurement s and f rom finite element method are analyzed to demonst rate that the disturbed zones should be considered in the displacement back analysis of the ship lock slopes of the Three Gorges Project and that elasticity is the feasible constitutive relation. Secondly the mechanical and physical properties of the disturbed zones are int roduced and the methods for considering disturbed zones are dis2 cussed. Finally the elastic moduli of both the primary rockmasses and their disturbed zones are back2analyzed by an error back2propagation neural network (BP network) and genetic algorithm based model.