Shear Creep Behavior of Open-Pit Clay and Development of a Fractional-Order Model
摘要
It is difficult to accurately describe the creep behaviour of the traditional open-pit mine clay slope because of its complex sliding zone creep mechanical characteristics. To solve this problem, a four-element fractional-order clay creep model is innovatively constructed based on component model theory and fractional calculus theory, which can accurately describe the accelerated creep process. Considering the dynamic evolution of rock mass during creep, the function expressions of rock strain and time are established. The least square method is used to verify and analyze the test data. The results show that the model established in this study has an excellent fitting effect on the experimental data, and the correlation coefficients are more significant than 0.98. The curves of parameters E1, W1, α, E2, W2 are all exponential functions with the increase of axial stress. The decay creep rate increases gradually with the increase of the α order of the parameter. With the rise of the β order of the parameter, the steady-state time of the rock decreases gradually. This model verified and analysed the creep characteristics of a specific peaty soil in Yunnan Province and a particular granitic soil in Gansu Province. It is found that the model is also suitable for accelerated creep under different lithology conditions, and the application range of the fractional order creep model is extended. The research results can provide a solid theoretical basis for the practical engineering application of clay slope slip zone treatment in open-pit coal mines.