闹市区超深基坑开挖的控制爆破技术

采取控制爆破技术,可解决闹市区地层复杂的大方量超深岩质基坑开挖的问题,有效缩短工期,降低成本。主爆区使用较大孔径(φ90 mm)爆破孔控制成本,提高效率;临边区采用小孔径静态破碎辅助机械破岩,减弱围护结构上的动荷载;重点保护文物建筑侧面钻多排超深大孔径减振孔(φ165 mm),严格控制爆破振动。主爆区炮孔使用电子雷管长、短延时结合,控制药量、逐孔起爆的同时控制单次振动持续时间,降低对附近居民区的影响。居民区、重点文物保护处振动值均在国家安全规程允许范围,未因爆破施工产生"扰民"与"民扰"纠纷。

Controlled blasting technique for ultra-deep foundation pits in downtown area

Excavation problern for large-scale ulrra-deep rock foundation pits with complicated rock in downtown area,controlled blasting technology was adopted,which could shorten the construction period and reduce costs effectively.For the main blasting area,blasting holes with large aperture(φ90 mm) were adopted to control the costs and improve the efficiency,while for border areas,small-aperture static crushing aid machinery was adopted for rock breaking to weaken the dynamic load on the envelop enclosure;For cultural relics and buildings under key protection,multiple rows of ultra-deep large-aperture shock relieve holes(φ165 mm) were sidetracked to control the blasting vibration strictly.The blast holes in the main blasting area,electronic detonators with long and short delay were combined to use,the explosive charge was controlled,the blast holes were detonated one by one,and the blasting time of each single time of vibration was controlled,so that the psychological influences on the neighboring residents were reduced The vibration value at each of the residential areas and the cultural relics under key protection was within the scope permitted by the national safety regulations,and no"disturbance to residents" or "disturbance from residents" occurred due to the blasting construction.