Creep Model and Parameter Evolution Law of Sandstone
In order to gain a deeper understanding of the viscoelastic mechanical behavior of rocks,an improved Maxwell model was established.According to the results of sandstone creep tests,the feasibility of the model was verified.On this basis,a method was proposed to obtain the model parameters at different loading times,then,fitting and sensitivity analysis were carried out on the results obtained by the proposed method.The research results indicate that the improved Maxwell model can characterize the viscoelastic properties of sandstone,and the relaxation time is sensitive to the stress level,while the fractional derivative is just the opposite.The fractional derivative is positively correlated with the development of internal cracks in rocks.The steady-state creep deformation process of rock is the process of transition from viscoelasticity to elastic viscosity.In fractional order evolution equations,coefficient a mainly regulates the decay rate of fractional derivative,while coefficient b reflects the way in which the fractional derivative decayed.This research findings provide a reference for clarifying the physical significance of model parameters and revealing the entire process of rock creep.
Improved Maxwell modelSensitivity analysisFractional derivativeFractional order evolution equation
万方数据
维普
