摘要
以玉溪—磨憨铁路普洱车站的超高填方工程为依托,借助ABAQUS有限元软件,研究超高填方路堤荷载下传统刚性桩和柔性桩复合地基桩体的受荷模式及路基稳定性。传统的刚性桩复合地基路堤中心处PHC管桩,桩身所受剪力和弯矩较低,PHC管桩的抗弯性能、抗剪性能未得到充分的利用;而传统的柔性桩复合地基则表现为路堤边桩侧向变形大,桩体柔性弯曲明显,路堤安全性相对较低等特点。在确保路堤安全的前提下,提出一种兼顾工程成本的超高填方荷载下刚柔组合桩复合地基优化设计方法,即将刚性桩布置于潜在滑裂面剪入口或剪出口位置,其余位置布置柔性桩。并借助有限元数值模拟方法对其加固机理及效果进行分析。研究结果表明:当刚性桩布置在剪入口位置时,能显著减少路堤的侧向变形以及坡肩处路堤顶面的竖向变形,其存在可直接阻止潜在滑裂面的进一步发展和贯通;而将刚性桩布置在剪出口位置,亦能减少路堤的侧向变形,但效果并不显著;且其能分担剪出口处桩周土体所受的剪切应力,使其塑性区向四周分散。2 种优化方案下路堤安全系数均较常规柔性桩复合地基安全系数有显著提升。
Based on the ultra-high filling project of Yuxi-Mohan Railway Pu'er Station, the ABAQUS finite element software was used to study the loading mode and subgrade stability of traditional rigid pile and flexible pile composite foundation under ultra-high fill embankment load. The PHC pipe pile in the center of the traditional rigid pile composite foundation embankment is low in shear strength and bending moment, and the bending and shear properties of PHC pipe piles are not fully utilized;The traditional flexible pile composite foundation is characterized by large lateral deformation value of the embankment side pile, flexible bending of the pile body and relatively low safety of the embankment. In order to ensure the safety of embankment, and at the same time take into account the engineering cost, an optimal design method for composite foundation of rigid-flexible composite pile under ultrahigh fill load was proposed. The rigid pile was arranged at the location of the potential slip surface shearing or shearing exit, and the flexible pile at the rest of the position was arranged. Then its reinforcement mechanism and effect were analyzed by finite element numerical simulation method. The results show that the rigid pile is arranged at the shearing entrance position, which can significantly reduces the lateral deformation of the embankment and the vertical deformation of the top surface of the embankment at the shoulder, and its existence can directly prevent further development and penetration of potential slip surfaces. And the rigid pile is arranged at the shearing exit position, which can reduce the lateral deformation of the embankment, but the effect is not significant, and the existence can share the shear stress of the soil around the pile at the shearing outlet, so that the plastic zone is dispersed around. And the safety factor values of the embankments under the two optimization schemes are significantly improved compared with the conventional flexible pile composite foundation.
作者
豆红强
俞仰航
聂文峰
王浩
陈雷
张蕊
DOU Hongqiang;YU Yanghang;NIE Wenfeng;WANG Hao;CHEN Lei;ZHANG Rui(College of Environment and Resources, Fuzhou University, Fuzhou 350116, China;Geological Engineering Fujian Provincial University Research Center, Fuzhou 350116, China;Kunming Survey, Design and Research Institute Co. Ltd., CREEC, Kunming 650200, China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2019年第10期2552-2562,共11页
Journal of Central South University:Science and Technology
基金
福建省自然科学基金资助项目(2017J05061)
国家自然科学基金资助项目(41602294)~~
关键词
超高填方
复合地基
刚柔组合桩
滑裂面
优化设计
ultrahigh fill
composite foundation
rigid-flexible pile
sliding surface
optimized design
