摘要:
针对地质灾害高风险区段埋地管道所面临的落石冲击威胁,为深入探究其动力响应特性,本文通过缩尺模型试验与数值模拟相结合的方法,系统研究了埋地管道的动力响应特性。建立的试验模型缩尺比例为1:10,采用落锤冲击试验装置,结合LS-DYNA有限元分析,探讨了管道埋深、壁厚、冲击参数、管道参数和土体特性(土体弹性模量和管土摩擦系数)对埋地管道的影响规律。试验结果表明:同一冲击高度下,管道埋深和壁厚越大,应变峰值越小;落锤偏心冲击时,冲击点偏离管道中心后,对管道上下截面影响降低;冲击高度越高,管道中部应变峰值越大。数值模拟表明:管道最大应力和应变与管道直径、内压、冲击速度正相关,与冲击偏距、土体弹性模量、管道埋深负相关;管土摩擦系数增大对管道应力应变影响有限,超过0.3后影响甚微。基于Pearson相关性分析,各参数影响程度为:冲击偏距>管道内压>管道直径>土体弹性模量>管土摩擦系数,其中管道内压、管道直径、管土摩擦系数与应变正相关,土体弹性模量、冲击偏距与应变负相关,落石冲击偏距和管道内压对埋地管道影响中等偏强相关。研究成果可为高风险区域埋地管道的安全设计提供依据。
Abstract:
In view of the rockfall impact threat faced by buried pipelines in high-risk areas of geological disasters, in order to further explore its dynamic response characteristics, this paper systematically studied the dynamic response characteristics of buried pipelines through the combination of scale model test and numerical simulation. Its purpose is to dig deep into these characteristics. During the experiment, this study, firstly, constructed a test model at a geometric scale ratio of 1:10. And at the same time, a drop hammer impact test device combined with LS-DYNA finite element analysis was used. Based on these above, the influence laws of pipe burial depth, wall thickness, impact parameters, pipe parameters, and soil properties (including soil elastic modulus and pipe-soil friction coefficient) on buried pipelines were explored. The test results show that at the same impact height, the peak strain decreases as the pipeline’s burial depth and wall thickness increase. When facing the eccentric drop hammer impacts, the influence on the upper and lower cross-sections of the pipeline diminishes as the impact point deviates from the pipeline center. Additionally, a higher impact height corresponds to a greater peak strain in the middle section of the pipeline.The numerical simulation results indicate that the maximum stress and strain of the pipeline are positively correlated with pipeline diameter, internal pressure, and impact velocity, while negatively correlated with impact eccentricity, soil elastic modulus, and pipeline burial depth. Moreover, the increase in the pipe-soil friction coefficient has a limited impact on pipeline stress and strain, and this effect becomes negligible when it exceeds 0.3.Based on Pearson correlation analysis, the order of influence degree of each parameter is impact eccentricity first, then pipeline internal pressure, then pipeline diameter, then soil elastic modulus, then pipe-soil friction coefficient last. Among them, pipeline internal pressure, pipeline diameter, and pipe-soil friction coefficient are positively correlated with strain, while soil elastic modulus and impact eccentricity are negatively correlated with strain. The rockfall impact eccentricity and pipeline internal pressure have a moderate to strong correlation with the impact on buried pipelines.The research results can provide a basis for the safety design of buried pipelines in high-risk areas.