摘要
基于入和没入硬层时有限元数值模拟对比分析和持力层不同时同场地现场对比试验资料分析,对大直径超长灌注桩的承载潜力问题进行了探讨.结果表明:(1)大直径超长桩入和没入桩端硬层时其承载性能会有很大区别.桩入硬层后其承载力大大提高,其极限承载力为没入硬层的3.8倍以上;(2)通过桩底注浆使持力层强度提高后,大直径超长桩的承载力大大提高.和注浆前相比,注浆后桩的承载力提高了0.27—1.0倍以上.和非注浆的桩相比,注浆桩的承载力为非注浆桩的1.25—1.61倍以上;(3)有好的天然持力层时,应设法使大直径超长桩进入该持力层;无好的天然持力层时,可进行人工桩底注浆使桩端岩土层强度提高;(4)当大直径超长桩有了好的持力层后,应使桩顶的沉降尽可能的大,这样可使桩的承载潜力充分地发挥出来.
Based on the field loading tests and FEM numerical simulation analysis, the paper probes into the potential bearing capacity of large diameter and super-long bored-cast-place piles. Conclusions are drawn as follows： Firstly, the bearing behavior is different greatly when the pile penetrates into hard soil layer and when it does not. The bearing capacity of the pile is increased greatly-its hearing capacity being 3.8 times as much as the pile that doesn＇t penetrate into hard soil layer. Secondly, the bearing properties of large diameter and super-long bored-cast-place piles is improved greatly after the bearing layer is reinforced by pile bottom grouting. The bearing capacity of pile after the bottom grouting is 0.27-1.0 times greater than the pile＇ that precedes bottom grouting. The bearing capacity of grouting piles is 1.25-1.61 times as much as that of the non-grouting piles. Thirdly, when there is a strong natural hearing layer, the large diameter and super-long bored-cast-place piles would penetrate into the bearing layer. When there isn＇t strong natural bearing layer, the hearing properties of pile end soil layer can he enhanced through pile bottom grouting. Finally, with a strong hearing layer, the tip settlement of large diameter and super-long bored-cast-place piles should he as large as possible in order to bring the hearing capacity of pile into fully play.
出处
《西安建筑科技大学学报（自然科学版）》
CSCD
北大核心
2006年第3期333-338,共6页
Journal of Xi'an University of Architecture & Technology(Natural Science Edition)
基金
上海市交通运输规划与管理重点学科建设资助项目(2005)
上海市教委科研资助项目(05FZ03)
关键词
承载潜力
大直径超长灌注桩
持力层
现场试验
数值模拟
the potential bearing capacity
large diameter and super-long cast-in-situ pile
bearing layer
field tests
numerical simulation
