Abstract:

Three-dimensional finite element method is used to analyze the stress and deformation behavior of cut-off wall of concrete faced rockfill dam on deep overburden foundation. The Duncan-Chang E-B model is used to simulate the constitutive relationship between rockfill and overburden material. The contact friction elements are set to simulate the interaction between the concrete structures and the overburden and cushion materials. The influences of staged-filling scheme, construction rate of dam body and construction sequence on stress-deformation behavior of the cut-off wall are discussed. In addition, the stress-deformation behavior of the suspended cut-off wall is also analyzed. Based on the numerical analysis, it is concluded that the staged-filling of dam body has small impact on the stress and deformation of the cut-off wall, whereas high construction rate may cause large stresses and displacements of the wall during completion period (tensile stress reaches 3MPa, deformation along the river direction amounts to 15cm), and the sequence of constructing cut-off wall in later stage could reduce the tensile stress by 2.42MPa and the deformation along river direction by 85%. A small depth of suspended cut-off wall could also improve its stress and deformation behavior.

Key words: hydraulic structure, concrete faced rockfill dam, cut-off wall, stress and deformation behavior, numerical analysis