Abstract: Perilous rock is widely distributed in mountainous areas and on excavated slopes and can lead to a serious geological disaster.Where there is developed rock cavity, support-anchorage combined technology can be used to effectively control the perilous rock.By converting the load on perilous rock into the normal force, tangential force and bending moment acting on the main controlling structural plane, a calculation method is established for the fracture angle and joint fracture strength factor of rock near the end of control fissure in perilous rock.Based on this, the formula for calculating the stability coefficient of perilous rock is proposed.A calculation method for the support and anchorage force needed in controlling perilous rock is established based on fracture mechanics and then a method is proposed on this base for determining the sectional dimensions of support and the anchor bolt number.Real case study has proven the rationality and effectiveness of this method.It is an effective supplement and improvement to the relevant technical specifications.

Key words: Rockmass mechanics, Perilous rock, Fracture strength factor, Support and anchorage, Calculation method