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针对城市路桥箱梁水压爆破环境复杂、技术难度高的特点,结合实际工程,采用动力有限元分析软件研究了箱梁在爆炸冲击波和爆生气体气泡膨胀作用下的破坏机理,讨论了药包的布置、微差起爆时间对箱梁破碎的影响。分析表明:对称布药、同时起爆的方案不利于中隔梁的破碎,主要是中隔梁两侧压差太小;采用微差爆破可以克服压差过小的缺点,合理的微差时间为5 ms左右;采用交叉布药、同时起爆的方案时,爆炸能量分布均匀,有利于改善爆破破碎效果,也避免了压差小的缺点;箱梁的破坏模拟效果与实际爆破效果相吻合,表明采用数值仿真技术可以很好地从力学角度揭示箱梁水压爆破的破坏机理,再现箱梁水压爆破的破坏过程,预判爆破参数对爆破效果的影响。
In view of the complex environment and high technical difficulty of urban road-bridge box girder hydraulic blasting, the failure mechanism of the box girder under the explosion shock wave and the gas expansion of the blasting gas is studied by using the dynamic finite element analysis software. The layout of the micro-differential detonation time on the impact of broken box girder. The analysis shows that the solution of symmetric drug delivery and simultaneous detonation is not conducive to the breakage of the septal beams. The main difference is that the pressure difference on both sides of the septal beam is too small. Using the differential blasting can overcome the shortcoming of the pressure drop being too small. 5 ms; using the cross-drug, simultaneous detonation scheme, the explosive energy distribution is uniform, is conducive to improving the blasting and crushing effect, but also to avoid the shortcomings of small pressure differential; box girder failure simulation results and the actual blasting results are consistent, indicating that The numerical simulation technique can well reveal the failure mechanism of box girder hydraulic blasting from the mechanics perspective, reproduce the failure process of box girder hydraulic blasting and predict the influence of blasting parameters on the blasting effect.