| The contact problem is a very widespread problem in hydraulic engineering and geotechnical engineering. The key to the solution is to establish a mathematical and mechanical model to reflect the nature of contact of structures. The main research contents with creative points are as follows:1. The contact problem related to hydraulic and geotechnical engineering issummarized. The characteristics of the joint are discussed, especially the type and the performance of the concrete key groove. The state of art of the contact problem and the numerical analysis method are summarized, too.2. The variation principle of the 3-D contact problem is introduced, the related formulas based on the finite element method are derived, and the contact mode and condition of the boundary are discussed.3. A model named shear slide model is presented, which can be used to simulate the mechanical property of the contact surface between the structure and its adjacent object.4. The structural type, geometry property, force transfer mode and performanceof various types of key grooves are first studied fully such as single key groove, two-way key groove and multi-way key groove. The relations between the initial normal and shear apertures of the key groove are derived. A nonlinear constitutive equation named the key groove shear transfer model is presented, in which the initial aperture of the joint can be considered. In the model, the direction, the shape and the shear strength of the key groove can be considered, so the variation law and the contact characteristics of the key groove can be truly reflected.5. A variable incremental search method used for the solution of the nonlinear space contact problem is presented, in which the calculation stability can be ensured. A nonlinear contact analysis program named FCSAP is developed. A rapid solution method, in which the coefficient matrix does not need to be resolved, is developed to solve the special problem in which the contact region is much smaller than the entire region.6. In combination with the application to the upstream lock head engineering of the ship lift in the Three Gorges Project, the influence of cross construction joints on the integrity of the massive concrete structure is researched. Based on the analysis of the arrangement form, the key type and the initial joint aperture of the cross construction joints in the upstream lock head, the influence of the joint aperture on the contact condition and the stress and displacement of the structure is studied, the influence of the joint arrangement form and contact type on the structural stress and displacement is also discussed. At the end, a proposal for joint arrangement and calculationis presented for the improvement of the structural integrity.7. In combination with the application to the permanent ship lock engineering in the Three Gorges Project, the interactions between the structure and the foundation are studied. By the computer simulation method, the law of variation of the aperture between the structure and the rock mass induced by the hydration heat and the variation of external temperature is researched for the construction and operation periods of the lock head concrete structure. Also studied are the influences of concrete structure type on the contact condition of the joints between the structure and the rock foundation and on the structural stress distribution. In the end, the strength and stiffness of the first lock head is reasonably evaluated.8. The applications to a few calculation examples and engineering practice show the correctness, rationality and validity of the key groove shear transfer model, the shear slide model, the variable increment search method for the solution of contact problem, and the program developed for the nonlinear contact problem, presented in this paper. Compared with the part shear transfer model and the complete shear transfer model are often used currently, the influence of the construction joints with key groove on the integrity of massive concrete structur...
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