Soft rock would display the characteristics of elasticity and viscoelasticity under low stress

of elasticity

plasticity and viscoelasticity under higher stress and of elasticity

plasticity

viscoelasticity and viscoplasticity under very high stress .In order to describe these characteristics comprehensively

firstly the paper brought forward two nonlinear components of creep body and plastic cranny body

and combined them with KELVIN body describing the deceleration creep and HOKE body describing the instantaneous elasticity to gain a new multiple rheological model .Then it used the model to simulate the results of the multi-step incremental cycling loading and unloading creep test of soft rock and drew a conclusion that the new model could effectively describe the creep properties of soft rock under different stress level

especially the properties of the cranny-closed phase and the creep-accelerated phase so that it could be popularly used in engineering practice.