黄土地基H-U组合荷载作用下扩底桩承载特性研究
Study on the Bearing Characteristics of Belled Pile Under Combined H-U Load in Loess Soil
陈阳 1吴武强 1訾凡 2耿芳杰 1王伟伟 3赵宇飞4
作者信息
- 1. 西安理工大学岩土工程所,陕西西安 710048
- 2. 中国有色金属工业西安勘察设计研究院有限公司,陕西西安 710061
- 3. 中铁十四局集团建筑工程有限公司,山东济南 250101
- 4. 中国水利水电科学研究院,北京 100038
- 折叠
摘要
为研究水平-上拔(H-U)组合荷载作用下荷载倾角和扩径比对扩底桩抗拔承载特性的影响,开展了黄土地基中4组荷载倾角θ(0°、15°、30°、60°)和2组扩径比λ(1.5、2.0)下的抗拔承载特性试验.对比分析了不同工况下的荷载位移曲线、桩身应变和桩侧土压力分布规律,探讨了扩底桩抗拔承载性能与荷载角度、扩径比之间的关系.进一步探究了荷载顺序、长径比和抗剪强度等因素对H-U组合荷载下破坏包络线的影响.研究结果表明:当θ=0°时,λ由1.5提高至2.0时,扩底桩的极限承载力Tλ=2较Tλ=1.5提高了 126％;随着荷载倾角的增加,当θ＞30°时,λ增大对扩底桩的极限承载力提高效果降低.H-U联合荷载作用下桩体承载力随着长径比(L/d)和土体抗剪强度的增加而增大,扩底桩主要通过扩大端克服桩周土体抗力,从而提高单桩抗拔承载性能.
Abstract
To study the influence of inclination angle and expanded diameter ratio of inclined uplift load(H-U)on the pull-out bearing characteristics of belled piles in loess area,pullout tests of 4 load angles θ(0°,15°,30°,60°)and 2 expanded diameter ratios λ(1.5,2.0)were performed.The load displacement curves,strain variation,and distribution of earth pressure under different engineering scenarios were compared according to the tests results.In addition,the relationship between the pull-out bearing performance of belled pile with respect to the load inclination and expanded diameter ratio were explored.Further,the influential factors such as load sequence,length to diameter ratio,and shear strength on the failure envelope under H-U combined loads were investigated.Results indicate that the ultimate bearing capacity T of the belled pile increased by 126％with λ increases from 1.5 to 2.0 when θ=0°.With the increase of λ,increment of the ultimate bearing capacity of belled pile decreased.The ultimate bearing capacity under H-U combined load increases with the length to diameter ratio L/d and the shear strength of the soil.Soil resistance around the enlarged part contributes to the uplift bearing capacity of the pile.
关键词
黄土/扩底桩/组合荷载/承载特性/包络线Key words
loess/belled pile/combined load/bearing characteristic/failure envelope引用本文复制引用
基金项目
国家自然科学基金项目(52008338)
中国水利水电科学研究院水利部水工程建设与安全重点实验室开放基金项目(IWHR-ENGI-202305)
陕西省博士后科研项目(2023BSHYDZZ138)
出版年
2024
NETL
NSTL
万方数据