Effect of previous cyclic loading on deformation characteristics of dam materials

Using dynamic triaxial tests, the effect of previous cyclic loading on capability of anti-deformation dam materials is studied. The results show that the anti-deformation capability is enhanced obviously when the dam materials are stabilized under the previous cyclic loading. It is considered that the further appropriate cyclic loading can not cause more particle breakage and internal redirection as are basically completed under the initial dynamic stress, leading to enhancing of anti-deformation capability and reduction of deformation. A general expression is proposed to describe the effect of the previous cyclic loading on the deformation of coarse materials. The anti-deformation capability of coarse materials only relates with k, which shows the sensitivity of the coarse materials to the previous cyclic loading, and it represents the degree of difficulty of particle breakage and internal redirection under later cyclic loading when they are stabilized under the previous cyclic loading. The value of k just relates with the absorption force and has nothing to do with parent rock, shape, gradation and density and so on. With the decrease of k, the sensitivity of the coarse materials to the previous cyclic loading is larger accordingly, and vice versa.