Study of creep characteristics of red mudstone filling and fractional five-element nonlinear creep model
In order to reveal the creep mechanical characteristics of red mudstone filling,triaxial CU creep test with graded loading of red mudstone filling in Gansu Province was carried out,and the creep characteristics such as the axial creep,creep rate and stress-strain isochronous curves of red mudstone filled with different moisture contents and stress levels were analyzed.Based on the characteristic analyses of creep curves of red mudstone filling,fractional calculus was introduced to construct a fractional five-element nonlinear creep model suitable for red mudstone filling in Gansu Province,and the model parameters were identified and analyzed.The results show that the red mudstone filling in Gansu Province has obvious creep characteristics,showing nonlinear attenuation creep,and the creep deformation increases significantly with the increase of moisture content and deflection stress.The stress-strain isochronous curves show nonlinear characteristics and obvious inflection point,and the long-term strength of the Gansu red mudstone filling is 0.6-0.8 times the instantaneous strength.The constructed model can accurately describe the creep characteristics of Gansu red mudstone filling,and the fitting effect on the experimental results is significantly better than those of the Burgers and Merchant models.
red mudstone fillingtriaxial CU creep testcreep propertyfractional calculusnonlinear creep model
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