爆破地震荷载作用下承插式HDPE管道动力失效机制

承插式管道接口更易受到外界荷载破坏导致管道失效，为保证爆破开挖过程中邻近承插式高密度聚乙烯（high-density polyethylene，HDPE）波纹管道的安全运营，控制爆破振动荷载对管道的影响是重点关注内容。通过全尺度预埋单段HDPE波纹管道现场试验，得到管道的振动速度和动应变响应数据，结合LS-DYNA数值模拟软件分别建立了无承插接口管道与含弹性密封圈的承插式HDPE波纹管道；利用现场试验数据验证了无承插口管道模型参数的可靠性，并对比分析了承插式管道的结构位移、振动速度、有效应力的响应规律与失效机制；结合现行规范，根据管道响应规律与接口允许旋转角度计算得到了承插式管道的安全振动速度。研究结果表明:有承插口管道的合振速、合位移和有效应力大于无承插口管道；在同一截面上，有承插口管道迎爆侧的合振速和有效应力更大，而最大合位移出现在截面的背爆侧；管道合位移与合振速在轴线中心处截面最大，并向两端不断减小，有承插口管道中心合位移更大；通过接口允许旋转角度得到此类工况条件下的承插式管道的安全振速为24.77 cm/s。

Dynamic failure mechanism of HDPE pipelines with a gasketed bell and spigot joint subjected to blasting seismic load

Pipelines with a gasketed bell and spigot joint are more vulnerable to external load damage, leading to pipeline failure. To ensure the safe operation of adjacent high-density polyethylene (HDPE) bellows during blasting excavation, control of the influence of blasting vibration load on the pipeline is the main focus. The vibration velocity and dynamic strain response data of the pipeline were collected from the field test of a full-scale embedded single-segment HDPE bellow. The HDPE bellow models without socket contact and with an elastic sealing ring were established using the LS-DYNA numerical simulation software. The reliability of the model parameters of the HDPE bellows without a joint was verified by the field test data, and the response laws and failure mechanisms of the structural displacement, vibration velocity, and effective stress of the HDPE bellows with a gasketed bell and spigot joint were compared and analyzed. The safe vibration velocity of the pipe was determined using the pipeline response law and the allowable rotation angle of the interface in conjunction with the current specification. The research results show that the resultant vibration velocity, resultant displacement, and effective stress of the bellow with a gasketed bell and spigot joint are greater than those of the bellow without a joint. At the same cross-section, the resultant vibration velocity and effective stress on the explosion side of the bellow with a gasketed bell and spigot joint are higher, and the maximum resultant displacement occurs on the back of the explosion side of the cross-section. Along the axis direction of the pipeline, the resultant displacement and the resultant vibration velocity of the pipeline decrease continuously from the center to both ends of the pipeline, and the resultant displacement of the pipeline with a gasketed bell and spigot joint is larger. The safe vibration velocity of the pipeline with a gasketed bell and spigot joint under such working conditions is 24.77 cm/s, according to the allowable rotation angle of the interface.