ABSTRACT
Water is another factor of major importance to slope stability analyses. A primary objective of slope stability analysis is estimation of a factor of safety for the considered slope and slide mass. When reinforcement with tensioned bolts is considered, the factor of safety may be written in the form where the first term on the right is the unbolted slope safety factor and the second term on the right is the improvement obtained by bolting. Quantitative analysis of actual surface mine bolting cases shows that bolting provides very little improvement in the unbolted safety factor at bolt spacings of the order of bench height, say, 50 ft more or less. Horizontal spacing can be much less, but decreased spacing comes at increased cost. Generally, bolting open-pit mine rock slopes is not economical except in unusual circumstances, for example, where an in-pit crusher requires protection. In civil works, public safety often justifies the cost of maintaining stable slopes using bolting methods.
