The Anisotropy Of Tailings And Its Application In Analysis Of Stability Of Dam

The sedimentation process of non-spheral grains may lead to directional variation, or anisotropy, of soil properties. It has long been recognized that soil anisotropy significantly affect the behavior of earth structures. The stability analysis of anisotropic tailings dam is very important because tailings dam often influences the life and property safety of people in a large area. Therefore, this paper focused on the anisotropy of tailings, and the results were applied in an engineering example. The anisotropy of tailings were studied by controlling inclination angle of bedding plane, initial void ratio and normal stress in the modified direct shear tests. Finally, an anisotropic model was introduced to evaluate the stability of a typical tailings dam numerically.First, it was found that the peak friction angle firstly decreased and then increased with the increasing of inclination angle of bedding plane. The peak friction angle when the inclination angle is 90 was far more than that of zero degree inclination angle. The minimum peak friction angle emerged when the inclination angle is around 25 . In addition, the difference of maximum and minimum residual friction angle is around two degree. In contrast, the difference of peak friction angle was around eight degree. Moreover, with the variation of normal stress the curves of peak friction angle versus inclination angle were similar, and lager normal stress led to less friction angle. With the variation of void ratio the peak friction angle of loose sand was far less than that of dense sand, but the residual value almost remained constant.Second, the dilatancy of tailings with initial void ratio 0.84 or 1.09 were studied through the analysis of corresponding variation of specimen volume. Then, it was found that dilation decreased with the increasing of initial void ratio under the conditions of same inclination angle, and contraction continued if initial void ratio reached a certain value. The results consisted with other studies. Whereas, the most important was that dilatancy can be influenced remarkably by inclination angle of bedding plane. A physical model of rigid block containing dentation interface was used to describe the process of dilative behavior under the conditions of different inclination angle of bedding plane in this paper. Finally, an anisotropic model of sand strength was summarized based on the experimental research. The anisotropic model was used to calculate the stability of a tailings dam containing homogeneous material. The results of numerical simulation showed that the stability of tailings dam considering anisotropic model was 4.84% less than that of isotropic case.