循环荷载作用下格栅防护柔性埋地管道的性能分析  

Performance of flexible buried pipes reinforced by geogrids under cyclic loading

作　　者：肖成志 何晨曦 王嘉勇 XIAO Cheng-zhi;HE Chen-xi;WANG Jia-yong(School of Civil and Transportation Engineering,Hebei University of Technology,Tianjin 300401,China)

机构地区：[1]河北工业大学土木与交通学院

出　　处：《岩土工程学报》2018年第10期1852-1861,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(50909032);河北省自然科学基金项目(E2014202038);河北省研究生创新资助项目(CXZZSS2017027)

摘　　要：交通循环荷载下埋地管道性能与防护是当前研究的重点问题,首先针对格栅加筋柔性管道开展试验研究,分析管道埋深H为3D（D为管道外径）时循环荷载水平和频率、首层格栅埋深、长度、层间距和筋材层数对管道力学与变形性能的影响,试验结果表明：首层格栅最佳埋深u为0.4B（B为加载板宽度）,最佳层间距ug为0.5B,最佳铺设长度L为5D;增加格栅层数能显著增强土体,从而有效减少管道变形和加载板沉降;提高荷载水平或降低荷载频率使管道变形、加载板沉降和格栅应变整体显著增加;格栅应变随其与加载板中心的距离增加而减小,格栅中心点应变随循环次数增加呈现先增加后减少的趋势。进而,基于有限元数值模拟分析管道埋深H、加载板宽度B和管径D对管道力学性能的影响,数值结果表明增加管道埋深或减小加载板宽度,管道径向变形减小;同等荷载作用下,减小管径时管道径向变形增大,筋材加筋效果减弱,适当增加管道直径,有利于筋材加筋作用的充分发挥,从而减小管道径向变形。The study on protection performance of buried pipes under cyclic loading has been increasingly concerned. Firstly, a series of laboratory tests are conducted to investigate the mechanical performance of buried pipes during cyclic loading when the buried depth of pipes is 3 D（D, external diameter of pipes）. The results show that the optimum embedment depth of the uppermost reinforcement, spacing of geogrid layers and length of reinforcement are 0.4 B（B, width of loading plates）, 0.5 B and 5 D, respectively. Adding the numbers of layers of geogrids can significantly enhance the strength of soils and thus reduce the deformation of pipes and settlements of loading plates. It is pronounced that higher level of loading or lower frequency can affect remarkably the mechanical performance of buried pipes. Increasing the level of cyclic loading or lowering frequency of loads can result in the increase of radial deformations of pipes, settlements of loading plates and strains of geogrids. The strains of reinforcement decrease with the increase of distance away from the center of loading plates, and those of geogrids in the center tend to increase firstly and then decrease with the increase of cycles of loads. Furthermore, based on the numerical simulation method, the mechanical properties of pipes under different buried depths of pipelines, H, width of loading plates, B, and pipe diameter, D, are presented. The increasing buried depth or decreasing width of loading plates may reduce the radial deformations of pipes. The reinforcement effect is weakened for the pipes with smaller diameters, leading to the increase of deformations of pipes. However, the reinforcement plays a significant role in reducing the deformations of pipes with greater diameters.

关 键 词：土工格栅 埋地管道 模型试验 数值模拟 循环荷载 

分 类 号：TU472.34[建筑科学—结构工程] TU990.3[建筑科学—土工工程]