超高层建筑受飞机撞击后坍塌过程模拟分析

Simulation of collapse process of super high-rise buildings by aircraft collision

为了解飞机撞击超高层建筑并引起油箱爆炸所致建筑坍塌的特征,使用基于颗粒流的PFC 3D分析程序对其撞击、爆炸及坍塌过程进行模拟。以核心筒-框架结构的超高层建筑为研究对象建立了飞机撞击模型,并引入三维爆炸模型。设计飞机撞击速度为900 km/h,撞击高度为建筑正面250 m和100 m处。对两种高度撞击后的建筑坍塌过程进行模拟,结果表明:两种坍塌都包含撞击和爆炸两种作用,直接撞击作用并不能造成建筑的坍塌,爆炸是建筑坍塌的直接原因。但两者坍塌至稳定的时间不同,撞击高度250 m所用时间为151.28 s,而撞击高度100 m所用时间为196.08 s;最终残骸的分布不同,前者分布于撞击反方向,后者分布于四周;坍塌过程不同,前者为倒塌,后者为坐塌,即上部建筑结构重力作用导致下部结构坐塌破坏;最终坍塌结果不同,前者下部建筑结构完好,后者完全破坏。

In order to understand the collapse process of high-rise buildings caused by the aircraft collision and fuel tank explosion, PFC 3D based on particle flow was employed to simulate the collision, explosion and collapse process. The high-rise building with the frame-core tube was the research object. The aircraft model was constructed, and the three-dimensional explosion model was proposed. The hitting speed of the aircraft was 900 krn/h. The collision were at the 250 m and 100 m of building frontage. Building collapse process was simulated after the collisions at the two structural heights. Results show that the two collapses take place under the actions of collision and explosion. The direct collision cannot cause the collapse, while the explosion can. The time durations from the start of collapse to stabilization are 151.28 s and 196.08 s for the 250 m and 100 m hit respectively. The distribution of debris due to the 250 m hit is in the opposite direction of collision, while that due to the 100 m hit is around the building. The collapse due to the 250 m hit is overturning type, while that due to the 100 m hit is the vertical collapse caused by the instability of bottom stories under tremendous gravity load of upper stories. The bottom stories coule be in good shape after the collapse due to the 250 m hit, while the entire structure could be destroyed after the collapse due to the 100 m hit.