为研究爆炸作用后二次起爆对单箱三室混凝土箱梁的破坏行为，开展节段箱梁试件箱外/箱内连续爆炸试验。在10 kg TNT药柱爆炸作用后，施加5 kg TNT药柱继续作用，观测箱梁试件毁伤及动态响应。利用LS-DYNA软件分析了TNT当量、爆炸距离及起爆位置对箱梁破坏形态及动态响应的影响。结果表明:5 kg TNT炸药在中间箱室底板中心正上方 0。35 m处二次起爆后，中间箱室顶板破洞进一步增大，底板破洞沿横、纵桥向长度分别为 48。50 cm、62。50 cm，底板中心钢筋凹陷18。30 cm，两侧腹板有明显损伤。采用10 kg、5 kg TNT分别对 3 个箱室进行箱外/箱内连续爆炸作用，且二次起爆为内部接触爆时，箱室顶、底板均出现贯穿性破洞，底板破洞均大于顶板。相较于药柱位于箱室底板上方0。35 m，采用接触起爆时，箱室顶板沿横、纵桥向破洞长度分别减小21。2%、33。8%，底板破洞长度分别增加103。9%、113。2%。
Model test and mechanism analysis of concrete box girder explosion damage under continuous explosion action inside and outside box
In order to study the damage behavior of a single-box three-chamber concrete box girder caused by a secondary detonation after first blast,a continuous explosion test of section box girder is carried out inside and outside the box.After the explosion of 10 kg TNT,the 5 kg TNT is applied to continue the action,and the damage and dynamic response of the box girder specimen are observed.The LS-DYNA software is used to analyze the effects of TNT equivalent,explosion distance and detonation position on the damage pattern and dynamic response of the box girder.The results substantiate that:after the second explosion of 5 kg TNT 0.35 m above the center of the bottom plate of the intermediate box,the hole in the roof of the intermediate box is further enlarged.The length of the hole of the bottom plate along the transverse and longitudinal bridge are 48.50 cm and 62.50 cm respectively,with the steel bar in the center of the bottom plate sunken 18.30 cm and the two sides of the abdominal plate obviously damaged.10 kg and 5 kg TNT are used to carry out the continuous explosion outside and inside the box to the three box chambers respectively.When the secondary explosion is a contact detonation,penetrating holes appear in the top and the bottom of the box chamber,and the holes of the bottom plate are larger than that of the top plate.Compared with the pillars 0.35 m above the bottom of the chamber,when the contact explosion is adopted,the length of the transverse and longitudinal holes in the top plate of the chamber decreases by 21.2%and 33.8%respectively,and the length of the bottom plate holes increases by 103.9%and 113.2%respectively.
万方数据
维普
