Hard brittle rock would occur creep failure like the soft rock,therefore,the investigations on the creep behavior of brittle hard rock is of great significance to the stability of surrounding rock.To character-ize the effect of the initial hardness and compactness of rock on its creep behavior,an improved fractional nonlinear viscous body,whose viscosity coefficient is proportional to the power of the initial elastic modu-lus,was proposed to describe the viscoelastic characteristics in the decay and steady creep stages.Accord-ing to the theory of continuum damage mechanics,a fractional nonlinear damage visco-plastic body consid-ering time-dependent damage,which can describe the mechanical behavior of accelerated creep,was estab-lished by introducing a damage factor.Furthermore,connecting Hooke's body,the improved fractional non-linear viscous body and the fractional nonlinear damage visco-plastic body in series,a fractional creep damage model of brittle hard rock was established,and its rationality was verified by an experimental data.The experimental curve is in good agreement with the theoretical curve of the model,which shows that the model can better describe the whole creep process of brittle hard rock.Next,the sensitivity of the parame-ters was analyzed,and the influence of the parameters on the creep behavior is discussed.The results show the relevant parameters play an important role in correctly describing the creep characteristics of hard brit-tle rock.
creep modelbrittle hard rockfractional-order calculustime-dependent damage
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