Study on coupling model of anchorage force loss and time-dependent deformation of rock-soil mass

The anchorage force loss of prestressed anchor cables is the key factor causing the failure of engineering. It is vital to study the time-dependent variation law of the anchorage force. When the anchor cable interacts with rock-soil mass for a long time,the stress is equal but the deformation is different. The loss of the anchorage force needs to consider the influence of the interaction between free and anchorage sections of the anchor cable with the rock-soil mass respectively. The Hooke and the Generalized Kelvin bodies are used to simulate the anchor cable and the rock-soil mass respectively. Considering that the free section of the anchor cable is in parallel with the corresponding rock-soil mass but the anchorage section is in series with the rock-soil mass,a coupling model of the anchor cable and rock-soil mass creep is established,and its constitutive,relaxation and creep equations are derived. The rationality and accuracy of the model are verified by comparing with the existing models and experiment data,and the influence of parameters of the anchor cable and the rock-soil mass on the anchorage force loss rate is analyzed. The results show that the loss rate of the anchorage force increases with increasing the equivalent elastic modulus of the anchor cable but decreases with increasing the hysteretic elastic modulus and the viscosity coefficient of the rock-soil mass. When the instantaneous elastic modulus or the viscosity coefficient of the rock-soil mass in free and anchorage sections changes by the same amount,the change of the loss rate is equal. The change of the loss rate caused by the change of the hysteretic elastic modulus in the free section is more than that in the anchorage section. The model can more truly reflect the regular of the anchorage force loss. © 2022, Science Press. All right reserved.