The Appliance of 3-D Composite Layerrd Element in RCC Arch Dam

摘要

A numerical calculation method and a new type element of EFM for the simulation of the RCC dams is presented. It takes into account the more relevant features of RCC, such as the transversely isotropic, the layered character, the strength unequal to tension and compress and the discontinuities. The element presented is made up of a serial of layers to simulate the concrete layer and interlaminar sand mortar. Due to construction conditions, RCC dam often occurs weak intercalated layer defects, which may lead to changes in the distributions of stress and displacement in the structure, and make the weak layers to be the failure control positions of the dam structure as a result of its poor strength. In order to ascertain the stress state in the layered dam structure, a simplified analytical method is suggested in this paper. The Mohr- Coulomb's failure criteria expressed in general stress state is used to evaluation the safety of element. A 3-D model of RCC Dam, built in South-West of China, is used to perform the corresponding analyses. It is found that the local stress concentrations do exist in the boundary area of the layered RCC dam structure. The result shows the location of third height to dam heel in upstream dam will be crack between layers. So it is very dangerous for arch dam. In the locations of third height to dam toe and dam crest of the downstream of the dam will occur the stresses concentration, so some of engineer measures must be adopted to avoid the damage. The factor effecting interlaminar shear stress is analyzed. The main factors of causing the layer stresses are temperature changer, the different expansion coefficient between body and layeres and the Poisson ratio. In a word, the methodologies are feasible. And the element of EFM should be introduced in the RCC dam design.