To understand the viaduct collapse process and the motion behavior of the viaduct collapse process ac-curately,the high-speed photography was used to monitor the viaduct collapse process. The problem of insufficient light of high-speed photography at night was solved by using highlight LED lamp belt. The method and formula of a-nalysis and calculation of the results from high-speed photography were put forward. The relationship between the via-duct collapse displacement and velocity and acceleration with time were obtained. The velocity and acceleration for-mulas of the viaduct collapse process of the reference light with east,central and west were achieved by the data fit-ting. The maximum velocity of the corresponding part of the viaduct was 8. 56 m/s,8. 70 m/s and 8. 64 m/s respec-tively,and the maximum acceleration was -61. 02 m/s2 ,-82. 60 m/s2 and -64. 95 m/s2 respectively. The viaduct collapse time was 0. 95~1. 00 s. Results showed that the viaduct collapse time and velocity were related to the deto-nating sequence and the initiation interval. The viaduct collapse maximum velocity was smaller than free fall velocity of the corresponding viaduct bridge,due to the combined effects of the supporting role of broken concrete blocks and constrain force from the piers and the diversionary effect from the subsequent collapse of the bridge body. The study provided important reference for the design of blasting scheme,the hazard assessment of vibration impact and the safety protection.%为了详细了解高架桥桥体的塌落过程，研究高架桥桥体在塌落过程中的运动规律，运用高速摄像技术对高架桥桥体的塌落过程进行了观测。采用高亮LED灯带解决了夜间进行高速摄影时的进光量不足的问题；提出了进行高速摄像结果分析与计算的方法和公式；获得了塌落位移、速度和加速度随时间的变化关系；拟合获得了参考灯带东侧、中部和西侧桥体在塌落过程中的速度和加速度公式；可以得到对应部分桥体的速度最大值分别为8.56 m/s、8.70 m/s、8.64 m/s，加速度最大值分别为-61.02 m/s2、-82.60 m/s2、-64.95 m/s2，桥体的塌落时间为0.95~1.00 s。结果表明：不同部位桥体塌落时间和塌落速度与起爆顺序和起爆时差有一定的关系，受桥墩爆破后碎混凝土块及钢筋的支撑作用和后塌落桥体的牵制作用共同影响，导致高架桥桥体塌落速度最大值小于对应桥体的自由落体速度值。本研究对于爆破方案设计、振动冲击危害评估及安全防护都有极为重要的参考价值。
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