Rock Bolts and Rock Dowels
Rock bolts are used to tie individual unstable rocks and potentially unstable rock structure into the slope. There are static (rock dowels) and tensioned rock bolts. Tensioned rock bolts should be used where individual blocks or rock structures have already experienced strain along discontinuities. Tensioned reinforcements improve the resistance to future sliding or toppling.
In most cases static bolts (rock dowels) should be used. The logic behind a static bolt is that if the structure is safe enough to drill into and install rock bolts, it already has an inherent factor of safety. If the stability of the structure is adversely affected in the future the static bolt will take the load, and keep the rock slope stable.