摘要
针对120 m高钢筋混凝土排气塔爆破拆除工程,利用有限元软件ANSYS/LS-DYNA,采用分离式共节点模型,对其倒塌过程进行数值模拟研究,并结合录像资料进行对比,分析其倒塌过程中结构支撑部、断裂部、顶部位置的失稳破坏过程及其运动状态。结果表明:长细比很大的筒体结构,因其自重大惯性大,并且结构外形有截面突变,下坐过程中冲击破坏与加速下落相互作用,故筒体在倒塌时在断面缺陷部位急剧收缩极易发生断裂;由模拟得0.2 s时爆破切口形成,应力集中首先在切口顶角出现,倾倒一定角度后背部拉裂,应力集中转移至切口底角;前期应力重分布时间约4.5 s,9 s时在结构75 m位置处出现裂隙,筒体分离,下筒体绕塑性铰缓慢倾倒,上筒体自由落体;录像得8.5 s时在结构约70 m位置出现裂隙约为截面突变处;模拟倒塌长度范围为104 m,在触地时速度达最大,上筒体最大触地速度为49 m/s,下筒体速度达最大为29 m/s;模拟倒塌时间约12 s实际为11.8 s,与实际工程吻合得较好。
Aiming at the blasting demolition project of a 120 m high reinforced concrete exhaust tower,the finite element software ANSYS/LS-DYNA was used to simulate the collapse process by a separate common node model.Compared with the video data,the movement state of the structural support part,the fracture part,and the top position of the instability failure process were analyzed.The results show that the cylinder structure with a large slenderness ratio was prone to fracture due to its large self-weight inertia and section mutation in the structure shape,and the interaction between impact failure and accelerated fall appeared in the process of sitting down.It was found that the blasting cut was formed at 0.2 s,and the stress concentration first appeared was at the top angle of the cut.After tipping at a certain angle,the back part was pulled and the stress concentration was transferred to the bottom angle of the cut.Furthermore,the initial stress redistribution time was at about 4.5 s,and there was a crack at 75 m of the structure at 9 s.Meanwhile,the cylinder was separated,the lower cylinder was slowly overturned around the plastic hinge,and the upper cylinder fell freely.The recorded video showed that the crack appeared at the position of the structure at about 70 m with a sudden mutation of the cross section at 8.5 s.The simulated collapse length was 104 m,the vibration velocity of cylinder collapse reached the maximum,the maximum velocity of the upper cylinder was 49 m/s,and the maximum velocity of the lower cylinder was 29 m/s.Besides,the simulated collapse time was about 12 s and the actual collapse time was 11.8 s,these two times were very close.
作者
高文乐
段耀奎
柳鹏辉
方昌华
李传水
吴超
GAO Wen-le;DUAN Yao-kui;LIU Peng-hui;FANG Chang-hua;LI Chuan-shui;WU Chao(School of Civil Engineering and Architecture,Shandong University of Science and Technology,Qingdao 266590,China;Shandong Tongli Blasting Co.,Ltd.,Weifang 262400,China;Zaozhuang Jinxing Blasting Co.,Ltd.,Zaozhuang 277116,China)
出处
《爆破》
CSCD
北大核心
2022年第1期101-106,129,共7页
Blasting
基金
深部高应力岩巷掏槽爆破破岩过程与机理研究(51-874189)。
关键词
钢筋混凝土排气塔
定向爆破
数值模拟
倒塌过程分析
reinforced concrete exhaust tower
directional blasting
numerical simulation
collapse process analysis
