[Objective] The accumulation is a typical wide-graded soil, which is susceptible to internal erosion by fine particle loss under seepage, and the prediction of the amount of erosion is crucial to the engineering safety. [Methods] To address the problem that the existing erosion prediction model does not consider the effect of stress states, this paper constructs the coupled control equation and numerical method of accumulations internal erosion on the theory of seepage-erosion-stress, and verifies the reliability and accuracy of the method by using the triaxial erosion shear experimental data. Based on the numerical simulation data of internal erosion with seepage-erosion-stress coupling, a model for characterizing erosion evolution of accumulations considering the effect of seepage-erosion-stress coupling was established using volume strain, rock content, average seepage velocity and time as input parameters. [Results] A preliminary quantitative description of the erosion evolution of accumulations under complex stress states has been realized, and the effects of rock content and volume strain on the erosion characteristics of accumulations and their intrinsic causes have been investigated. [Conclusion] The results show that, under the condition of the soil skeleton was not destroyed by erosion, the constructed model can effectively predict the fine particles erosion evolution process of accumulations with different stress states and different rock content; the increase of rock content inhibits the erosion of accumulations by increasing the seepage distance of pore water and decreasing the average seepage velocity; the increase of volume strain caused by shear dilation of accumulations under deviatoric stress state is the intrinsic reason for the enhancement of the erosion of accumulations.
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