Abstract: Simulation model experiment, with a model scale of 1:2, is carried out to study the mechanisms of transferring force and stress state of nut column structure of the ship lift in the Three Gorges Project, and to compare the variation of stresses and deformation of each member between construction period and running period. The experiment shows that in running period the definite load end is tensioned significantly, tension stresses exist in pre  embedded steel member convex teeth and grouting materials, and the tension stress values are in the allowable range of design. Under the combined action of prestress and definite load, the relationship of displacement, strain with the load is nearly linear, and the effect of transferring force among the grouting material and steel members is good. Destructive test under the condition of ignoring the prestress reinforcement effect and increasing the test load to 50% of design load shows that, the safe bearing capacity of the nut column is 0.7 times the value of the design load. It states that the prestress is indispensable.

Key words: ship lift of Three-Gorges dam  ,   nut column structure ,    extrusion convex tooth ,    pre -embedded steel members  ,   prestressed bolt ,    prestressed reinforcing bar