doi:10.16186/j.cnki.1673-9787.2020040027

Received:2020/04/07

Revised:2020/07/14

Published:2021/11/15

Study on the rock creep constitutive model based on fractional derivative

HU Qizhi1, WANG Zhichao1, DING Zhigang1,2

1.Civil Architecture and Environment， Hubei University of Technology， Wuhan 430068 ， Hubei， China;2.China Jiaotong Brige South Engineering Co.， Ltd. ， Beijing  101149 ， China

Abstract:Since the composite element model cannot describe the disadvantage of the nonlinear creep acceleration stage of the rock ， the soft element based on the fractional order theory was connected in series with the spring element and a nonlinear viscoplastic composite composed of a friction member and a Newton viscous potin parallel to form an four-element creep model based on the fractional derivative that could better describe the whole process of rock creep. The three process characteristics of rock creep were analyzed ， and the expression of the four-element model was derived. Combining the creep experiment data of green schist ， Wanzhou red bed sandstone and Changshan salt rock of Jinping Hydropower station ， the fractional order model was fitted ， and it was found that by adjusting the order of the fractional order in the fractional model ， it was possible to better simulate the nonlinear gradual change process with the constant creep velocity of rock in the creep stage ， and the fractional order model could also reflect the characteristics of the exponential function growth of the rock strain over time in the accelerated creep stage. By comparison ， it was believed that the fractional order model could well simulate the whole process of rock creep， and the model had simple combination and few parameters ， and had good practical application value.

Key words:fractional derivative;rock creep;acceleration phase;nonlinear;constitutive model

 基于分数阶导数的岩石蠕变本构模型研究_胡其志.pdf