摘要
某120 m钢筋混凝土烟囱待爆破拆除,其东侧60 m和南侧21 m有高压线路,南侧41 m有厂房,北侧8 m有一座待拆旧厂房。设计布置了一个爆破切口,切口高度3.2 m,切口圆心角225°;在切口两侧对称预开3.0 m×3.2 m三角形定向窗;在切口中心预开3.0 m×3.2 m减荷槽。共布置炮孔324个,总装药58.32 kg,分2段延迟起爆,总延迟时间210 ms。为防止烟囱爆后下坐,爆破前采用砖块水泥砂浆将东侧出灰口砌筑。为减小拆除爆破危害,采用3道减振堤降低振动;采用稻草帘、竹笆、钢丝网、双层密目安全网等措施防止飞石危害;采用消防车洒水进行爆后降尘。爆破后,烟囱按设计方向倾倒落地,无后坐与下坐;倒塌长度约115 m,爆堆高度约3 m,无飞石,二次飞溅最大距离约20 m,南侧41 m处振动监测最大值1.21 cm/s,对周围环境设施没有影响。
A 120 m reinforced concrete chimney needs explosion demolition,which located at 60 m east to high voltage line and 21 m south to a high voltage line,41m south to a workshop,and 8m north to an oht factory buihting. A blast cut was set up with the height of 3.2 meter with the central angle 225°. A triangle directional window with 3.0 m 3.2 m was arranged bilaterally symmetry of incision. A load reducing groove with 3.0 m 3.2 m was set up in the eenter of the cut. 324 blast holes and total explosive 58.32 kg were initiated by two delayed intervals with 210 ms. in order to prevent chimney sitting down after blasting,the bricks masonry cement mortar was set on the ash mouth at the east side before blasting. To reduce the demolition blasting harm,three anti-vibration dams were taken to reduce collapsing vibration. The straw shade, bamboo basketry, barbed wire, double layer mesh nyhm nets and other measures were used to prevent the flyrock. In addition, the fire fighting vehicle helped to prevent dust after blasting. Finally, the chimney collapsed on the ground according to the designed direction after blasting, without sit back or sit down. Meanwhile, the blasting collapse length was about 115 m and the blasting pile height was 3 m or so. The maximum blasting vibration monitored was 1.21 cm/s on the south 41 m and no damage effect was made on the surroundings.
出处
《爆破》
CSCD
北大核心
2016年第3期92-95,共4页
Blasting
关键词
120
m烟囱
爆破拆除
定向窗
减荷槽
120 m chimney
explosive demolition
directional windows
load reducing groove
