Directional Blasting Demolition Technology of 150m-High Reinforced Concrete Chimney and 75m Cooling Tower

This paper describes the successful experience of the directional control blasting demolition of 150m-high reinforced concrete chimney and 75m cooling tower of Shizuishan Power Plant in Ningxia. It emphatically describes the pretreatment measures, blasting cut shape and size, blasting parameters, detonating network and blasting safety technology of the directional window, oriented window and load reducing slot. This paper provides the method for opening the overlarge arch oriented window, opening the special-shape load reducing slot and dense mesh safety net cross-multilayer coverage as well as comprehensive protection method for anti-flyrock splash and vibration reduction. Especially, the blast holes for opening the special-shape load reducing slot and the herringbone column are centralized at the bottom and top, which not only reduces the drilling workload, but also reduces the maximum detonating explosive amount of single section, and also reduces the safety protection workload.