Energy-based method for analyzing accumulative plastic strain growth of tailing silt

In order to study the relationship between the accumulative plastic strain growth and the energy dissipation, and to further classify the pattern of the accumulative plastic strain growth, dynamic consolidated-undrained triaxial shear tests are conducted on tailing silts with different void ratios under different cyclic stress ratios. The energy dissipation in soil is divided into plastic strain and viscous accumulative energy dissipations. According to the relationships, failure modes of the accumulative plastic strain growth are reclassified, and the development of accumulative plastic strain is interpreted based on the improved energy dissipation mechanism. The research highlights that as the cyclic stress ratio keeps increasing, the rate of dissipation of viscous accumulative energy will exceed that of the plastic strain accumulative energy,and the development mode of accumulative plastic strain will turn from the stability to the failure. Furthermore, the failure modes are reasonably divided into four categories: stable type, stable damage type, damage type and collapse. Essentially, the plastic strain accumulative energy will dissipate due to the rearrangement among relatively large particles such as sand and silt grains. Similarly, the viscous accumulative energy will dissipate because of the relative slippage among clay particles and colloid particles under the relaxation of weak bound water in the double electrical layers. This energy dissipation mechanism is consistent with the proposed failure pattern of the accumulative plastic strain growth. The research results may provide a basis for further model researches on the accumulative plastic strain growth.