Behavior of plastic concrete diaphragm walls in three gorges project

The high earth and rockfill cofferdam of Three Gorges Project employs plastic concrete diaphragm walls as seepage barrier. In view of the importance and technical difficulty of the cofferdams, the behavior of plastic concrete and the diaphragm walls within the cofferdams was studied. Plastic concrete samples taken from concrete mixer in the dam site were tested by using I arge triaxial testing apparatus in Tsnghua University. Mechanical properties and parameters of Duncan Chang nonlinear elastic model were obtained. Test results indicated that, comparing with ordinary concrete, the materials have the features of low modulus of deformation and favorable impermeability. The analysis of stresses and deformations of the diaphragm walls was performed by means of finite element method (FEM), using parameters obtained from the result of triaxial tests. Calculation results were discussed.