Material Substitution Method To Improve The Arch Dam Stress Research

Arch dam is an important dam type and it plays a very prominent role in the construction of water conservancy and hydropower. With reasonable structure, beautiful shape, high security, and economic superiority, it has been widely used at home and abroad. However, during the process of operation, the arch dam will produce temperature load with the change of the temperature outside. As the temperature rises, the temperature load will increase the dam stress, while as the temperature drops, the temperature load will increase tensile stress of the dam. Considering that the concrete tensile strength is far lower than the compressive strength, under the temperature drop conditions the dam would crack because of excessive tensile stress. Consequently it will influence the dam safety.This paper tries to improve the stress of arch dam by replacing the dam body material. At present, the main method for arch dam stress analysis is finite element, the second is arch-cantilever method. Compared with arch-cantilever method, finite element method is more perfect and advanced in theory with higher calculation precision and stronger calculating function. The finite element method can solve many structure problems in size, load condition and complex boundary condition etc.. For example it can consider large orifice, complex foundation, gravity piers and irregular appearance, besides, it can simulate the construction stage and operation process of the arch dam, together with reasonably considering global stiffness of arch dam and the interaction between the dam and dam foundation. These are which the arch-cantilever method cannot solve. Because of these advantages, now the finite element method is being widely used for the dam stability and strength analysis at home and abroad and its use in concrete arch dam stress analysis and application has got more and more widely and deeply. It will gradually replace the arch-cantilevers method and become the main method for arch dam design.This paper first collect material for low elastic modulus concrete, understand the various performance and provide the theory basis for whether it can be used as the arch dam material.Then by using the finite element method as the analysis theory, the software ANSYS10.0as a platform, using APDL language to establish the command stream file and SOLID226unit to divide the units, we get a100m high arch dam model and use the direct coupling method to calculate the arch dam tensile stress. On one hand, we get the arch dam stress distributionin the cases of temperature rise and temperature drop. On the other hand, under the premise condition of temperature drop, we use low elastic modulus concrete dam instead of regional concrete dam with stress concentration. After computing, we find that low elastic modulus material replacement method can not only well improve the phenomenon of concentrated tensile stress in arch dam but also improve the security of the arch dam.