双排桩加固滑坡桥基模型试验与数值模拟研究
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摘要
滑坡段桥梁基础常采用抗滑桩作为支挡结构,但针对此类工况的研究成果却少见发表。目前,滑坡段桥基设计一般不考虑抗水平荷载作用,水平荷载常通过设计抗滑桩来承担,而实际上抗滑桩和桥基是相互作用的。文章以成兰铁路九寨沟双线大桥为研究背景,进行前后排抗滑桩支护滑坡桥基的模型试验,分析在前后两排抗滑桩的作用下桥基的变形情况和受力特性,并基于FLAC 3D软件讨论了不同埋置位置下双排抗滑桩对桥基的影响。结果表明:(1)后排抗滑桩水平的变形产生了较大的荷载作用于桥基上,且集中在承台附近;(2)数值模拟下的桥梁基桩受力特性与室内模型试验测试数据较为符合,证明了数值模拟的可行性;(3)后排抗滑桩和桥基之间有一个最佳距离,能起到充分减小桥基水平变形的作用,而前排抗滑桩应靠近桥基方能有效发挥其支护效果。
Although anti-slide piles are often used as retaining structure for bridge foundation in landslide section, few of research results have been published in the journal. At present, the anti-horizontal load is generally not considered in the design of bridge foundation in landslide section, and the horizontal load is usually borne by anti-slide pile. In fact, the anti-slide pile and the bridge foundation are interacted. Taking Jiuzhaigou double-line bridge of Chengdu-Lanzhou Railway as research background, this paper carries out the model test of the bridge foundation with front and rear anti-slide piles in landslide section, analyses the deformation and stress characteristics of the bridge foundation under the action of the front and rear anti-slide piles, and discusses the influence of the double-row anti-slide piles on the bridge foundation under different buried positions based on FLAC 3 D software. The results show that:(1) the large load produced by the horizontal deformation of the rear anti-slide pile acts on the bridge foundation and concentrates near the cap;(2) the stress characteristics of the bridge foundation pile under the numerical simulation are consistent with? the testing data of the indoor model test, which proves the feasibility of the numerical simulation;(3) there should be an optimum distance between the rear anti-slide pile and the bridge foundation, which can adequately reduce the horizontal deformation of the bridge foundation, but the front anti-slide pile should be close to the bridge foundation so as to effectively play its supporting role.
Although anti-slide piles are often used as retaining structure for bridge foundation in landslide section, few of research results have been published in the journal. At present, the anti-horizontal load is generally not considered in the design of bridge foundation in landslide section, and the horizontal load is usually borne by anti-slide pile. In fact, the anti-slide pile and the bridge foundation are interacted. Taking Jiuzhaigou double-line bridge of Chengdu-Lanzhou Railway as research background, this paper carries out the model test of the bridge foundation with front and rear anti-slide piles in landslide section, analyses the deformation and stress characteristics of the bridge foundation under the action of the front and rear anti-slide piles, and discusses the influence of the double-row anti-slide piles on the bridge foundation under different buried positions based on FLAC 3 D software. The results show that:(1) the large load produced by the horizontal deformation of the rear anti-slide pile acts on the bridge foundation and concentrates near the cap;(2) the stress characteristics of the bridge foundation pile under the numerical simulation are consistent with? the testing data of the indoor model test, which proves the feasibility of the numerical simulation;(3) there should be an optimum distance between the rear anti-slide pile and the bridge foundation, which can adequately reduce the horizontal deformation of the bridge foundation, but the front anti-slide pile should be close to the bridge foundation so as to effectively play its supporting role.
引文
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[3] 王华.桥基岸坡变形破坏机制物理模拟研究[J].岩土力学,2011,32(7):2034-2038.WANG Hua.Study of Deformation and Failure Mechanism of Bridge Foundation Slope with Physical Simulation Method [J].Rock & Soil Mechanics,2011,32(7):2034-2038.
[4] Souri A,Abufarsakh M,Voyiadjis G.Study of Static Lateral Behavior of Battered Pile Group Foundation at I-10 Twin Span Bridge using Three-dimensional Finite Element Modeling [J].Canadian Geotechnical Journal,2016,53:962-973.
[5] Sawwaf M E.Lateral Behavior of Vertical Pile Group Embedded in Stabilized Earth Slope [J].Journal of Geotechnical & Geoenvironmental Engineering,2008,134(7):1015-1020.
[6] 詹志峰,谢强,赵文.峡谷区岩质桥基岸坡稳定性系统分析方法研究[J].四川大学学报(工程科学版),2003,35(6):31-35.ZHAN Zhifeng,XIE Qiang,ZHAO Wen.Systematic Analysis Method Research on Rocky Slope Stability of Bridge Foundation in Gorge Area[J].Journal of Sichuan University,2003,35(6):31-35.
[7] Ruesta P F,Townsend F C.Evaluation of Laterally Loaded Pile Group at Roosevelt Bridge[J].Journal of Geotechnical & Geoenvironmental Engineering,1997,123(12):1153-1161.
[8] 刘建华,赵明华,杨明辉.高陡岩质边坡上桥梁基桩模型试验研究[J].岩土工程学报,2009,31(3):372-377.LIU Jianhua,ZHAO Minghua,YANG Minghui.Model Tests on Bridge Pile Foundation in High and Steep Rock Slopes[J].Chinese Journal of Geotechnical Engineering,2009,31(3):372-377.
[9] 李春鹏.锚固桩基础在高墩桥梁中的应用研究[D].北京:中国地质大学,2007.LI Chunpeng.A Study of Anchored Pile Foundation for High Pier Bridge[D].Beijing:China University of Geosciences,2007.
[10] 尹平保.陡坡段桩柱式桥梁桩基设计计算方法及试验研究[D].长沙:湖南大学,2013.YIN Pingbao.Design Method and Test Study of Pile-column Bridge Foundation in Steep Slope[D].Changsha:Hunan University,2013.
[11] Ismael N F.Lateral Load Tests on Bored Piles and Pile Groups in Sand [C]//International Symposium on Field Measurements in Geomechanics.Boston:September 24-27,2007:1-11.