爆炸载荷作用下焊缝区附近埋地X70钢管的动力响应分析

Dynamic Response Analysis of Buried X70 Steel Pipe near Weld Zone under Blast Loads

爆破地震效应对埋地管线的影响已成为工程爆破领域研究的热点。基于有限元软件ANSYS/LS-DYNA,以两种含Y型焊缝(坡口有2 mm余高焊缝和坡口无余高焊缝)的埋地X70钢管为例,数值模拟研究了TNT炸药量相同(4.473 kg)而炸高(60.0、85.0和110.0 cm)不同时,焊缝区附近埋地X70钢管的动力响应规律。研究表明:当炸高为60.0 cm时,焊缝有余高的管道受应力集中的影响较大,且先于焊缝无余高的管道进入屈服阶段;当炸高为60.0和85.0 cm时,焊缝有余高的管道整体抵抗变形的能力明显弱于焊缝无余高的管道。管土间的相互作用对X70管道背爆面有支撑作用,可有效地减小管道背爆面的位移。在相同条件下,焊缝有余高的X70管道抵抗振动的性能弱于焊缝无余高的管道,且与焊缝形式相比,炸高对含焊缝区的X70管道的最大振速起主要影响作用。

The influence of blasting seismic effect on buried pipes has been an important research hotspot in the field of engineering blasting.Taking two kinds of buried X70 steel pipes with Y-type welds(groove with2 mm weld reinforcement and groove without weld reinforcement)as examples,the dynamic behaviors of buried X70 steel pipes near the weld zone under blast loads were studied numerically by the finite element software ANSYS/LS-DYNA.The blast loads are formed by detonating 4.473 kg TNT with different blast heights(60.0,85.0 and 110.0 cm).The results show that when the blast height is 60.0 cm,the pipe with weld reinforcement is greatly affected by stress concentration and that it yields earlier than the pipe without weld reinforcement.When the blast heights are 60.0 cm and 85.0 cm,the ability of the pipe with weld reinforcement to resist deformation is significantly weaker than that of the pipe without weld reinforcement.The interaction between soil and pipe supports the explosion-back surface of the X70 pipe,which can effectively reduce the displacement of the explosion-back surface of the X70 pipe.Under the same conditions,the vibration resistance performance of the X70 pipe with weld reinforcement is weaker than that of pipe without weld reinforcement.Moreover,compared with the weld form,blast height plays an important role in the maximum vibration velocity of the X70 pipe near weld zone.