Abstract:

Anchor cable is closely contacted with geotechnical body through reaction support. After a certain pre-stress is applied on anchor cable, the geotechnical body also deforms under the action of pre-stress. Due to the creep property of geotechnical body, its deformation doesn’t complete instantaneously but changes with time, which causes the long-term loss of pre-stress. In this research, anchor cable is equivalent to two models (elasticity body and generalized Kelvin body), and geotechnical body is assumed to be model of H+nK (n≤3) which could simulate the creep property of geotechnical body. According to the coupling deformation between anchor cable and geotechnical body and the initial conditions, formulas of calculating the pre-stress of anchor cable with the change of time are obtained. Through comparison with the results of previous studies, the correctness of this model is verified. Moreover, the fitting curve could be more consistent with the measured pre-stress variation if the number of K in creep model of geotechnical body is increased and the relaxation of anchor cable stress is considered in the theoretical model.

Key words: anchor cable, creep, coupling model, stress relaxation, loss of pre-stress