Abstract
Time-dependent deformation of surrounding rock is a common phenomenon for tunnels situated in soft rock stratum or hard rock stratum with high geo-stress. To describe this phenomenon, a creep model combining the Abel dashpot and a non-Newton viscous element was adopted, and the analytical solution about the viscoelastoplastic deformation for circular tunnel was obtained based on this creep model. Then, the auxiliary tunnel of Jinping II hydropower station was taken as an example to reveal the influence of creep parameters on the creep deformation. The research shows that (1) the creep model can well describe the whole creep stage of rocks, that is, the decay, constant, and accelerated creep stages, (2) the creep deformation has a positive relation with the value of fractional order of Abel dashpot and the order of the non-Newton viscous element, and (3) the creep curves between test results and analytical solutions are well consistent with each other, which demonstrate the validity of the analytical solution.
Highlights
In former research, the creep behavior of surrounding rock is generally described by viscoelastic constitutive models
Advances in Civil Engineering researchers have done pioneer work in deriving the closedform solution of tunnel displacement using viscoelastoplastic models [9, 10]. erefore, in this article, a creep model, which consists of an elastic element, a non-Newtonian viscous element, an Abel element based on the fractional calculus theory, and a plastic element, is adopted to simulate the whole creep deformation stage of rocks
It reveals that the calculated results agree well with the test results, which shows that the creep model can describe the whole creep deformation stage of rock
Summary
E Abel dashpot based on the theory of fractional calculus can well describe the viscous characteristics of the viscous body between the ideal elastic body and the ideal fluid, and its expression is dcε(t) σ(t) η dtc. A creep model (Figure 1) combining the Abel dashpot and a non-Newton viscous element was adopted to simulate the whole creep deformation stage of rocks. E result showed that the long-term strength of marble is 130.1 MPa, and it underwent evident three-stage creep deformation when the axial compression stress exceeds 135.7 MPa. us, the creep curve at 135.7 MPa is chosen to validate this creep model. E calibrated parameters and simulated creep curves are shown in Table 1 and Figure 2, respectively It reveals that the calculated results agree well with the test results, which shows that the creep model can describe the whole creep deformation stage of rock
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