ABSTRACT
In Figure 1, α is the angle of countersink, β is the frictional angle between clips and anchor ring, γ is the frictional angle between clips and cable, F is the tensile force of cable, N is the total counter force on the contact surface between clips and anchor ring, F1 is the counter force of clips clamping cable, F2 is the frictional force between clips and cable. By equilibrium condition of the static force,
N Fcos( )α β 1 (1) N Fin( )α β 2 (2)
Divided one by the other
F F2 1 tan( )α β+ (3)
The condition of no sliding between clips and cable
1 INTRODUCTION
It is being used more and more widely in coal industry, because of its good flexibility, convenient construction, large anchoring depth and high prestress of small borehole cable (Kang et al. 2009). Study on cable in coal industry is changing from anchoring length and prestress to some details, such as diffusion and loss of prestress (Kang et al. 2011). But still some questions in application of small borehole cable in coal industry, just like only focusing on the length and strength, overlooking matched components such as anchorage, plate and et al. Many situations include slip of anchorage and cable being sheared caused cable failure directly, which would cause roof accident on account of large area supporting unloading suddenly. Sliding of anchorage on cable can produce spark, which brings threat to the management of gas and coal dust.
