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地层沉陷致埋地HDPE管道事故频发,主要原因之一是地层沉陷过程中所诱发的管道附加应力和变形剧增,从而导致管道破坏。已有研究成果大多集中于固定尺寸沉陷区域管道与周围土体力学特性的分析,尚无相关理论预测沉陷发展过程中管道力学响应特征变化规律。利用自制室内足尺大型模型试验系统,以粗砂为管道开挖沟槽回填料,通过调整模型箱底板的下沉模拟地层沉陷形成过程,研究埋地HDPE双壁波纹管道的受力变形特性及其上覆回填料土体的沉降分布规律。试验结果表明:1地层沉陷过程中HDPE管道的竖向变形符合修正高斯分布曲线;2随着土体沉陷的发展,管道顶部土压力随之增大,且试验管道顶部的土拱率由0.7增大到2.05,呈现出明显负土拱效应;3对于相同抗弯刚度管道,土体沉陷变形所致管道附加变形随管道上覆土层厚度的减小而减小;4随着管道抗弯刚度增加,埋地管道对于土体的沉降抑制作用愈加明显。
One of the main reasons for the frequent HDPE pipeline accidents caused by ground subsidence is the additional stress and deformation induced by the pipe during the subsidence process, which leads to pipeline destruction. The existing research results mainly focus on the analysis of the mechanical properties of the pipelines and the surrounding soil in the fixed-size subsidence area. There is no relevant theory to predict the variation of the pipe mechanical response characteristics during the development of the subsidence. The self-made indoor full-scale large-scale model test system was used to excavate the trench backfilling material with grit, and the subsidence of the mold box floor was simulated to simulate the formation of subsidence. The deformation characteristics of buried HDPE double- The overlying backfill soil subsidence distribution. The results show that: (1) The vertical deformation of HDPE pipe in the process of subsidence accords with the modified Gaussian distribution curve. (2) With the development of soil subsidence, the soil pressure at the top of the pipe increases, and the soil arching rate at the top of the test pipe increases from 0.7 To 2.05, showing obvious negative soil arching effect. 3 For the same bending stiffness pipe, the additional deformation of the pipe caused by soil subsidence decreases with the decrease of the thickness of the overburden; 4 as the pipe bending stiffness increases Buried pipe for the settlement of soil inhibition is even more obvious.