Aiming at the blasting demolition of the buildings embedded with a 43 m high steel structure boiler frame,the five boiler frames of No.2~No.6 boiler rooms were demolished by one-time directional blasting method and collapsed from north to south by span to east according to the order of No.2~No.6 boiler rooms.The reinforced concrete support columns were drilled and blasted,and the steel support columns were cut by a shaped energy cutter.Three cuts for the first-row of support columns of No.2 and No.3 boilers were set with a cut heigh of 6 m.Similarly,three 4m high cuts and two 3 m high cuts were set for the second-row and the third-row of support columns,respectively.The cut heights of the first-row and second-row of support columns of No.4~No.6 boilers were set as 6 m and 3.5 m,respectively.Additionally,the steel plates with a thickness less than 14 mm were cut by the SGPQ-15(180 g/m) cutter,and the steel plates with a thickness of 16mm and 20 mm were cut by the SGPQ-19(280 g/m) cutter.The total charge was 30.288 kg.During the explosion,the coal hopper room,boiler building roof and steel structure boiler frame overturned according to the designed direction.The frame of No.2 boiler sank at the moment of detonation,and the lower seat of No.5 column in the boiler room was placed after 0.25 seconds.Subsequently,the factory collapsed span by span from north to south and tilted towards the east with a detonation interval of 0.25 seconds.The collapse of the two stairwells were lagged significantly under the support of shear walls,and the stairwells toppled eastward under the impact of boiler overturning.The column between the upper and lower blasting cuts was compressed and collapsed during the tilting process of the column on the east side of the boiler room towards the east.The column was 16 m away from the chimney,and the upper part of the middle staircase,boiler,and shear wall were tilted forward.The main body was 14 m away from the chimney,and the closest distance of collapsed object to the chimney was 6 m.Both of the blasting flying stones and blasting vibration(0.28 cm/s) did not exceed the standard,and the blasting demolition did not cause any damage to surrounding buildings and facilities.