爆炸荷载下装配式桥墩损伤因素灰色关联分析

Grey Correlation Analysis of Damage Factors of Prefabricated Pier under Explosion Load

装配式桥墩在桥梁施工领域得到广泛的应用,常受偶然爆炸或恐怖袭击的打击影响。为研究爆炸荷载下装配式桥墩损伤因素的影响规律,采用ANSYS/Workbench建立了近场爆炸荷载作用下的装配式桥墩数值模型,基于桥墩剩余承载力,提出以破坏参数D作为抗爆性指标,以炸药当量、爆心距离、初始预应力大小、节段数和剪力键的设置为损伤因素,分析了5种因素对桥墩损伤程度影响。在此基础上,利用灰色关联分析法衡量爆炸荷载下装配式桥墩损伤因素之间关联度的指标与贡献度。结果表明:增大初始预应力、节段间设置剪力键其破坏参数D的综合降低率为32.1%、29.6%,均能有效降低墩柱的损伤,与装配式桥墩抗爆受损有良好的关联性;而增加剪力键高度和节段数为12%、7.2%,对墩柱损伤影响较小;5种因素对爆炸荷载下装配式桥墩损伤影响的关联度从大到小为:TNT当量、爆心距离、初张拉预应力、剪力键的设置、节段数量。装配式桥墩抗爆设计中,可优先考虑提高初张拉预应力大小、设置剪力键等关联度较大的因素,灰色关联分析法对爆炸荷载下装配式桥墩损伤因素分析具有一定的参考性。

Prefabricated piers are widely used in the field of bridge construction and are often affected by accidental explosions or terrorist attacks.In order to study the influence law of the damage factors of prefabricated bridge piers under explosion load,a numerical model of the prefabricated bridge piers under near-field explosion load has been established by ANSYS.Based on the residual bearing capacity of bridge piers,the damage parameter D is proposed as the anti-explosion index.The influence of five damage factors,including the explosive equivalent,the distance from the explosion center,the initial prestress,the number of segments and the setting of shear keys,on the damage degree of bridge piers is analyzed.On this basis,grey correlation analysis method is used to measure the degrees of correlation and contribution among the damage factors.The results show that the comprehensive reduction rates of failure parameter D are 32.1%and 29.6%by increasing the initial prestress and setting shear keys between segments,which can effectively reduce the damage of the piers and have a good correlation with the blast resistance of prefabricated piers.However,increasing the shear key height and segment number to 12%and 7.2%has a small effect on pier damage.The order from largest to smallest of the five factors in the correlation degree on the damage of the fabricated bridge piers under blast loading is:TNT equivalent,blast center distance,initial tensile prestress,shear key setting and segment number.In the anti-explosion design of prefabricated bridge piers,the factors of large correlations such as increasing the initial tensile prestress and setting shear keys can be given priority.The grey correlation analysis method has certain reference value for the analysis of damage factors of prefabricated bridge piers under explosive load.