Influence analysis of frequent blasting disturbance on the stability of toppling perilous rocks

The effective performance of the tensile properties of the rock in the rock bridge section of the main control structural plane is the key to maintaining the stability of the overturned dangerous rock mass, while the mechanical properties of the rock in the rock bridge section often deteriorate due to blasting disturbance near underground engineering, resulting in continuous decline of stability of dangerous rock mass. Firstly, based on the limit equilibrium theory for considering the influence of decayed explosion stress wave on the stability of dangerous rock mass, a stability evaluation method for overturned dangerous rock mass was constructed. Secondly, the micro cumulative damage variable of rock in the rock bridge section under the blasting load was obtained based on the Lemaitre equivalent principle. According to the weakening of the effective tensile area of rock, the tensile strength deterioration equation was obtained and verified by test results. Finally, according to such deterioration equation, the stability evaluation method for dangerous rock mass was modified. Based on engineering examples, the influence of related sensitive parameters on the stability of dangerous rock mass was analyzed. The research results showed that frequent blasting disturbance would deteriorate the mechanical properties of the main control plane. As the blasting intensity increases, the propagation distance of the explosive stress wave decreases, the deterioration of the mechanical properties of the rock in the rock bridge section intensified, resulting in a greater attenuation trend of its own stability coefficient. Moreover, the dumping load generated by the explosion on the dangerous rock mass was more sensitive than the deterioration of the mechanical properties of the rock mass.