| In this thesis, a load-displacement relation for a 7-strand steel cable bolt has been established. It is assumed that cable bolt performance is mainly determined by the interaction between the cable strand and grout. This interaction, in turn, is dependent on the cable's external shape, the mechanical and geological properties of the rock mass, the mechanical properties of the grout and the in-situ stress level.; A cable bolt's unique characteristics come from its twisted strand construction. A three dimensional parametric equation describing the cable bolt surface was established first. The assumption of contact forces between the cable bolt and grout is based on the analysis of relative displacements between them. The effect of stiffness of the grout and the rock mass is studied through a restrained thick wall cylinder analysis. This analysis leads to the development of elastic stress state in the grout. It is shown that there are four types of stress components in the grout: the radial compressive stress {dollar}sigmarmsb r{dollar} which reacts with the confining stiffness; the tensile hoop normal stress {dollar}sigmasbtheta{dollar} which controls fracturing of the grout; the hoop shear stress {dollar}sigmarmsb{lcub}rtheta{rcub}{dollar} and the axial shear stress {dollar}sigmarmsb{lcub}rz{rcub}{dollar}whose resultant controls the cable bolt's pull-out resistance.; Equations for two critical cable bolt loads--the linear elastic limit load and the ultimate bond load--were formulated based on mathematical and statistical analysis of cable test data conducted by Reichert and Goris. Reichert and Goris' test data on various cable embedment lengths has been reduced to form an embedment length factor. A post elastic model which describes the relation of confining stiffness, the basic friction angle and the dilation angle has been formed. The effect of in-situ stress is considered using a basic friction model. Finally, the load-displacement relation is derived based on the above developed loads and experimental analysis of displacements.; Effort has been made to implement this model in the numerical packages FLAC and UDEC. Using the modified FLAC and UDEC, laboratory cable bolt pull tests and the Winston Lake Mine quasi-AVOCA-longhole stope stability problem have been numerically modelled with good results. |
