Multi-factors influence of anchorage force on surrounding rock under coupling effect of creep rock mass and bolt/cable

Assuming that relative sliding does not occur to the coordinated deformation of bolt/cable and surrounding rock, a constitutive model of coupling effect between bolt/cable and creep surrounding rock is established to study the variation law of anchorage force on surrounding rock with time increasing, the parameters of physical-mechanics of bolt/cable and the mechanical parameters of surrounding rocks analyzed, and the sensitivity of the above parameters to anchorage force compared using sensitivity analysis method. Results show that the validity and effectiveness of the proposed constitutive model is verified by numerical simulation. And the main factors affecting the anchorage force for creep rock are diameter (D), elastic modulus (E (C)), and initial pre-stress force (F) of bolt/cable, viscoelastic modulus (E (R)), viscoelastic coefficient (eta (R)) and initial in situ stress (sigma (0)) of surrounding rocks, respectively. For bolt or cable, increasing the parameter values of D, E (C) and F can strengthen the anchorage force; while for surrounding rocks, large value of sigma (0) and small value of eta (R) are beneficial to the exertion of anchorage force. The sensitivities of these factors from high to low are D, E (R), sigma (0), E (C), F, eta (R), respectively. The result can provide some guidance for the formulation of on-site support scheme and parameters selection.