超大直径嵌岩桩基础竖向受荷性状研究

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摘要 研究目的:超大直径桩的应用越来越多,超大直径桩基础的工作性能是否仍可以采用常规的设计方法,需要进一步研究。本文基于夜郎河铁路特大桥的超大直径桩基础,结合具体地质情况采用FLAC^3D软件仿真模拟分析大直径单桩基础竖向受荷特性。
研究结论:(1)对于完全嵌入强度较高岩层的桩或上覆岩层强度较高的超大直径桩基础,当桩的长径比大于1.8时,桩基侧阻曲线形态表现为“上大下小”;随着桩长减短、长径比减小,桩上部侧阻逐渐减小,下部侧阻逐渐增大;当长径比很小时,变成“两端大、中间小”的形态;(2)只有当桩侧岩层弹模较小或上覆土层强度较低(如为黏土)的超大直径桩基础,侧阻曲线才表现为“上小下大”的形态,且桩侧岩层弹模越小,或上覆土层越弱,这种特征表现越明显;(3)超大直径桩的最优长径比小于3,比小直径桩的最优长径比小;(4)对于同直径的超大桩基础,桩侧阻力会根据桩侧岩层弹模的不同表现出三种不同的分布形态;(5)本研究成果可为超大直径桩基础的研究及应用提供指导和参考。

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	宋随弟
	彭雄志
	杨泉
	冯振兴
	郭伦波

关键词 ：嵌岩桩, 桩基础, 长径比, 竖向受荷, 侧阻

Abstract：Research purposes:There are more and more applications of super-large diameter piles. Further research is needed on the working performance of super-large diameter pile foundations and whether conventional design methods can still be used. In this paper, based on the super-large diameter pile foundation of the Yelanghe Railway Bridge, combined with the specific geological conditions, the FLAC^3D software is used to simulate and analyze the vertical load characteristics of the large-diameter single-pile foundation.
Research conclusions:(1) For rock-socketed piles that are completely embedded in strong rock formations or large-diameter pile foundations with high strength of overlying rock formations, when the length-diameter ratio of the piles is greater than 1.8, the lateral resistance curve of the pile foundation is shown as "large on the top and small on the bottom" shape. With the shortening of the pile length and the reduction of the length-diameter ratio, the upper lateral resistance of the pile gradually decreases and the lower lateral resistance gradually increases. When the length-diameter ratio is very small, it becomes a "big at both ends, small in the middle" shape. (2) Only when the elastic modulus of the rock layer on the side of the pile is small or the strength of the overlying soil layer is weak (such as clay) with a super large diameter pile foundation, the lateral resistance curve shows the shape of "small on the top and large on the bottom", and the smaller the elastic modulus of the rock layer on the side of the pile, or the weaker the overlying soil layer, the more obvious this characteristic is. (3) The optimal length-diameter ratio of super-large diameter piles is less than 3, which is smaller than that of small-diameter piles. (4) For the super-large diameter pile foundation of the same diameter, the pile lateral resistance will show three different distribution patterns according to the different elastic modulus of the pile side rock formation. (5) The research results can provide guidance and reference for the research and application of super-large diameter pile foundations.

Key words： rock-socketed pile pile foundation length-diameter ratio vertical load lateral resistance

收稿日期: 2022-09-26

PACS:

U24

作者简介: ** 宋随弟,1970年出生,男,教授级高级工程师。

引用本文:

宋随弟, 彭雄志, 杨泉, 冯振兴, 郭伦波. 超大直径嵌岩桩基础竖向受荷性状研究[J]. 铁道工程学报, 2023, 40(2): 47-52.
SONG Suidi, PENG Xiongzhi, YANG Quan, FENG Zhengxin, GUO Lunbo. Research on the Characters of Super-large Diameter Rock-socketed Pile Foundation under Vertical Load. Journal of Railway Engineering Society, 2023, 40(2): 47-52.

链接本文:

https://tdgcxb.crec.cn/CN/ 或 https://tdgcxb.crec.cn/CN/Y2023/V40/I2/47

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