Aiming at the blasting demolition problems of a 180 m reinforced concrete chimney in Wuhan Iron and Steel plant,which contains a herringbone large volume lining and an adjacent gas pipe,the feasibility of the opti-mization scheme of"digging large arched guide window and raising blasting incision"was demonstrated by the AN-SYS/LS-DYNA finite element software.The calculation results show that the collapse and accumulation speed of the inner lining is obviously greater than the closing speed of the blasting incision after it is generated.Meanwhile,the chimney may not be topple over under the influence of the accumulation body by using a general directional dumping scheme.However,the chimney will collapse by raising the height of blasting incision to 5.6 m and digging a large arched guide window which is 6.09 m wide and 8 m high.In addition,to ensure a good effect of blasting demolition,the auxiliary measures of mechanically removing the lining around the blasting incision and covering the surface of the blasting incision and gas pipeline with flexible protective layers composed of safety nets,barbed wires,geogrids and other composite materials were put forward.The actual demolition blasting results show that the chimney collapse process is smooth after the incision detonation,and the numerical simulation results are in good agreement with the actual situation.At the same time,the gap between the chimney root cylinder wall and the ground is filled with the accumulated objects after the collapse,and there is no damage to the adjacent gas pipe.Besides,the excavation of the oversized arched guide window not only realizes the relief of the accumulation materials,but also greatly reduces the workload of charging and protection.
关键词
钢筋混凝土烟囱/定向爆破/超大拱形导向窗
Key words
reinforced concrete chimney/directional blasting/oversized arched guide windows
维普
万方数据