Study On The Analysis Theory And Method Of The Influence Of Complex Concrete Dam Base To The Structure Behaviors Of Dam Body

Dam is a complex system including dam body and base. There exists complex interact between dam body, base, and load. Also, the reciprocity of creep between dam base and body, and stress-seepage field couple between dam and its base are something intricateo Anciently, study on dam body is rather abundant, but quite few on dam base. Aiming these hot and difficult spots in dam building, combining one of the great projects sponsored by national natural science fund (No. 50139030), and real projects analysis of Xin'anjiang dam and Longyangxia dam, this dissertation studied these complex problems mentioned hereinbefore. The main contents are as follows:(1) Concrete dam, especially high dam, endures great loads such as water and temperature that passes to its base. So stabilization of dam base is very important. Aiming at the different characteristics of concrete gravity dams and arch dams, the dissertation derived the relation between stress of the dam and their module parameters. Combined with Xin'anjiang dam and Longyangxia dam, the optimum module ratios are determined as 1.0 and 0.8. The results are important for dam base excavation and engineering disposal.(2) Arch dam can be regarded as an elastic ground cantilever system composed of vertical cantilever, horizontal arch, and torsion structures. The dissertation takes the arch dam as load diversion system of arch-cantilevers system located on the ground composed of elastic cantilever. The base is divided into finite block element. So, the stress and load that this system divided can be calculated. Combining analyzing Morrow Point dam on Colorado River with this method, the rationality of it is validated.(3) Generally, dam and base are operated in material viscidity status. By studying on the creep model of dam concrete and base rock, and combined them together, the coupling model of these factors is bringing forward. Using these theories, the physical cause of continual left displacement of Longyangxia dam; especially 4th dam section is analyzed.(4) Accidents of some arch dam show that dam failure mainly caused by crack or failure of their base rock, which is directly related with seepage in the rock. Rock seepage have an important influence on rock's mechanical character, and stress field in it. The stress field and seepage field should be studied as a coupled system. Thedissertation studied the mechanism, elastic and elasto-plastic analysis model, and finite element method of these coupling problems. As an example, the continual left displacement of Longyangxia dam is analyzed by this method.