The Stress Control Criterion Of Gravity Dam Based On H-version Adaptive FEM And The Consideration In Improving The Distribution Of The Stress In The Dam Heel

With the high development of computer technology, FEM gets broadly applied in the engineering. But the concrete gravity dam design norm is still to be the base with the material mechanics method, FEM can't be the main design standard. A reason is the stress singularity of the dam heel and toe. Many experts and scholars make a great deal of research to this, however the problem hasn't been got to resolve nicely.On the basis of studying and absorbing systematically the main theories of adaptive FEM, this paper studies that h-version adaptive FEM how to implement in the ANSYS program. In order to verify its credibility, this paper first applies it to a steel plate of L, and carries on the research to the influence of the control parameters. The result shows that the effect is good on the basis of adaptive FEM of ANSYS. And then, adaptive FEM is applied to study dam stress determination. Aiming at different height of dam and different ratio of elastic modulus of the dam and dam foundation, this paper made a lot of calculation. Some conclusions are obtained.For the given global energy error limit, the calculation results can meet the required error to use adaptive mesh strategy of ANSYS program, and the influence of controlling parameters of mesh size can be ignored, and the stress singularity of dam heel doesn't influence the convergence of adaptive calculation.For the different original gridding and no original gridding, the stress of dam foundation surface can achieve the approximate results if the same global energy error limit is adopted.There is a stable critical global energy error limit for gravity dam, moreover, the critical global energy error limit isn't influenced by the height of dam and ratio of elastic modulus. This paper draws the conclusion that the stable critical global energy error limit of the dam of rock foundation is 2.At last, in view of the case that big tensile stress exists in gravity dam heel, the author brings forward a proposal that sets a V slot in the upper stream of dam foundation to improving the stresses distributing of the dam heel zone, and besides, position and sizes of the V slot have been optimized. That provides new thought of the structure design of gravity dam.