冷却塔拆除爆破倒塌运动规律和结构变形力学分析

Analysis of the collapse movement law and structural deformation mechanics of cooling towers demolished by blasting

为了分析双曲线薄壁冷却塔在拆除爆破过程中的变形破坏特性,利用ANSYS/LS-DYNA有限元软件对冷却塔结构建立了整体式模型,并结合摄影资料对其倒塌历程进行了对比分析。结果表明:冷却塔人字柱、圈梁和塔壁会先后发生倒塌破坏,整个塔体随即在重力作用下形成倾覆力矩向预定方向倒塌。自身结构存在损伤的冷却塔,会导致其局部塔壁强度降低,在爆破过程中通常会出现大变形扭曲现象。冷却塔结构整体重量较大,在倒塌过程中会产生很大的塌落振动,对爆区附近桥面和桥墩进行振动监测发现,阻尼器的存在使得桥面振动频率远低于桥墩振动频率,高程差引起的高程放大效应使得桥面振动峰值成倍扩增。

To analyze the deformation and failure characteristics of the hyperbolic thin-walled cooling tower during blasting demolition,an integral model of the cooling tower structure was developed using ANSYS/LS-DYNA finite element software.The collapse process was compared and analyzed against photographic data.The results indicate that the herringbone column,ring beam,and tower wall of the cooling tower collapse and sustain damage sequentially.As the entire tower structure experiences an overturning moment due to gravity,it collapses in the predetermined direction.Structural damage to the cooling tower results in a reduction of local wall strength,leading to significant deformation and distortion during the blasting process.The substantial weight of the cooling tower generates considerable vibrations during the collapse.Vibration monitoring of the bridge deck and piers near the explosion area revealed that the presence of dampers causes the vibration frequency of the bridge deck to be significantly lower than that of the piers.This elevation difference creates an amplification effect,magnifying the peak vibration of the bridge deck several times.