院报 ›› 2022, Vol. 39 ›› Issue (1): 78-85.DOI: 10.11988/ckyyb.20200921

• 岩土工程 • 上一篇    下一篇

圆砾-泥岩组合地层坑中坑开挖对双排桩的影响

欧孝夺1,2,3, 黄中正1, 江杰1,2,3, 罗方正4, 梁亚华4   

  1. 1.广西大学 土木建筑工程学院,南宁 530004;
    2.工程防灾与结构安全教育部重点实验室,南宁 530004;
    3.广西金属尾矿安全防控工程技术研究中心,南宁 530004;
    4.中国建筑第八工程局有限公司,南宁 530028
  • 收稿日期:2020-09-09 修回日期:2020-10-19 出版日期:2022-01-01 发布日期:2022-01-14
  • 通讯作者: 江 杰(1979-),男,湖北麻城人,研究员,博士,主要从事城市地下工程与桩基工程研究。E-mail:jie_jiang001@126.com
  • 作者简介:欧孝夺(1970-),男,广西来宾人,教授,博士,主要从事城市地下工程与环境岩土工程研究。E-mail:ouxiaoduo@163.com
  • 基金资助:
    国家自然科学基金项目(51768006,51978179);广西科技计划项目(桂科AB17195035)

Influence of Pit-in-Pit Excavation on Double-row Piles in Composite Stratum of Round Gravel and Mudstone

OU Xiao-duo1,2,3, HUANG Zhong-zheng1, JIANG Jie1,2,3, LUO Fang-zheng4, LIANG Ya-hua4   

  1. 1. College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China;
    2. Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education, Guangxi University, Nanning 530004, China;
    3. Guangxi Engineering Research Center for Metallic Tailings Security Prevention and Control, Nanning 530004, China;
    4. China Construction Eighth Engineering Division Co., Ltd., Nanning 530028, China
  • Received:2020-09-09 Revised:2020-10-19 Online:2022-01-01 Published:2022-01-14

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摘要： 为研究双排桩在南宁圆砾-泥岩组合地层中的支护特性,以南宁地铁4号线某深基坑工程为依托,运用ABAQUS有限元软件和现场监测数据进行分析,得出双排桩在该地层有较好适用性的结论。然后在此基础上,进一步探讨坑趾系数、深度比在影响阈值左右范围变化以及不同土体强度弱化百分比的工况下,坑中坑开挖对双排桩的影响。结果表明各因素对双排桩支护效果的影响强弱依次为土体强度弱化百分比、坑趾系数、深度比;并提出以双排桩的最大侧移增长百分比是否>20%作为依据,初步评价内坑开挖对基坑安全稳定性的影响程度;最后通过分析各参数对应工况下基坑破坏的模式和原因,针对性地给出了相应的解决措施。

关键词: 双排桩, 坑中坑, 圆砾-泥岩组合地层, 数值模拟, 安全系数

Abstract: With a deep foundation pit project of Nanning Metro Line 4, we studied the supporting characteristics of double-row piles in round gravel mudstone composite stratum in Nanning using ABAQUS finite element software and field monitoring data, and concluded that double-row piles are well applicable in the round gravel mudstone composite stratum. We further investigated into the influence of pit-in-pit excavation on double-row piles under the conditions of different soil strength weakening percentages and the variations of pit toe coefficient and depth ratio around thresholds. Our findings suggest that the weakening of soil strength has the greatest influence on the supporting effect of double-row piles, followed by pit toe coefficient and depth ratio in sequence. Meanwhile, we propose to take whether the maximum increase percentage of lateral displacement of double-row piles exceeds 20% as the criterion to assess the influence degree of inner pit excavation on the safety and stability of foundation pit. In addition, by analyzing the failure modes and causes of the foundation pit under corresponding working conditions of each parameter, we gave corresponding countermeasures.

Key words: double-row piles, pit-in-pit, round gravel-mudstone mixed strata, numerical simulation, safety factor

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