The Effects of Bolts on the Stress-state in Visco-elastic Rock Masses around an Excavation

The effects of bolting in visco-elastic rock media are studied by analytical methods in this paper. After simplification, the concise expressions of stress state in confining rock, including bolting area, are given, by which the influences of bolting time, bolt spaces and prestresses and the lengths of bolts can be reflected. The emphasis is laid on the discussion of reasonable bolt lengths and some explicit conclusions are obtained,