Analysis on the Length of Rock Bolt with Underground Works under Explosion Load
In this paper based on the explosive stress wave theory, the mechanism for the broken rock zone’s formation and the character of the surrounding rock’s disfeature under blast loads are analyzed. On the basis of these works, the surround rock’s dynamic broken rock zone calculation formula is derived and for the anti-explosion reinforcement to the surrounding rock of tunnel segment bearing dynamic load is locked. In addition, the author also calculated and analyzed separately the necessary length of rock bolt for the reinforcement, consider of the first type to the forth type surrounding rock, different vertical critical explosion distance, different span. The curves are obtained between the length of rock bolt for the anti-explosion reinforcement of the surrounding rock and three factors are included: the span of underground opening, type of the surrounding rock, the distance between the center of charge and the vault.