城市地下工程的减震爆破技术

Cushion Blasting Technique for City Underground Project

介绍在城市建筑物下掘进地下工程,采用增加自由面,确定合理起爆时间间隔和周边眼隔孔装药等减震爆破技术。

Chong qing City underground project constructed by the 9th Engineering Division of Sichuan Coal Construction Engineering Department is more than 700 m in length; 12m in net span, and maximum net span is 15m. Underground blasting operation below crowded municipal architecture and buildings is carried on with aids of cushion blasting technique, monitoring and controlling blasting force to keep all the architecture and building safe. Main technical measures of blasting and main constructing method are: (1) blasting free holes are increased by using old holes; (2) constructing method of advanced guide hole is to drive roof firstly, then drive vertical walls, the finally,sublevel blaste; (3) millisecond delay blasting technology with 10 short-delay detonators and delay interval 100ms between 2 detonators is adopted to decrease seismic wave; (4) line holes are charged at intervals of a hole to decrease vibration; (5)charge is limited, charge per time is 0,9kg for I class architecture and 2,5kg for II class architecture to control blasting force; (6) holes are reasonably arranged to increase blasting efficiency. All the measures assure the project of successful construction and surface architdecture and building of safety.