岩土力学 ›› 2020, Vol. 41 ›› Issue (2): 399-407.doi: 10.16285/j.rsm.2019.0113

• 基础理论与实验研究 • 上一篇    下一篇

深厚淤泥质土中基坑开挖对基桩 影响的离心模型试验研究

王国辉1, 2, 3,陈文化1,聂庆科2, 3,陈军红2, 3,范晖红2,张川2   

  1. 1. 北京交通大学 土木建筑工程学院,北京 100044;2. 河北建设勘察研究院有限公司,河北 石家庄 050227; 3. 河北省岩土工程技术研究中心,河北 石家庄 050227
  • 收稿日期:2019-01-20 修回日期:2019-05-22 出版日期:2020-02-11 发布日期:2020-02-08
  • 通讯作者: 聂庆科,男,1965年生,硕士,正高级工程师,主要从事岩土工程理论研究与工程实践。E-mail:nieqingke2001@sina.com E-mail:wghlc666@sina.com
  • 作者简介:王国辉,男,1969年生,博士研究生,正高级工程师,主要从事岩土工程理论研究与工程实践。
  • 基金资助:
    河北省建设科技研究项目指令性计划(No. 2014-114)

Impacts of pit excavation on foundation piles in deep silty soil by centrifugal model tests

WANG Guo-hui1, 2, 3, CHEN Wen-hua1, NIE Qing-ke2, 3, CHEN Jun-hong2, 3, FAN Hui-hong2, ZHANG Chuan2   

  1. 1. School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China; 2. Hebei Research Institute of Construction and Geotechnical Investigation Co., Ltd., Shijiazhuang, Hebei 050227, China; 3. Research Center for Geotechnical Engineering Technology of Hebei Province, Shijiazhuang, Hebei 050227, China
  • Received:2019-01-20 Revised:2019-05-22 Online:2020-02-11 Published:2020-02-08
  • Contact: NIE Qing-ke, male,born in 1965, Master, Professor, Research interest: theoretical research and engineering practice of geotechnical engineering. E-mail:nieqingke2001@sina.com E-mail:wghlc666@sina.com
  • About author:WANG Guo-hui, male, born in 1969, PhD, Professor, Research interest: theoretical research and engineering practice of geotechnical engineering. E-mail: wghlc666@sina.com
  • Supported by:
    This work was supported by the Directive Program of Construction Science and Technology Research Project of Hebei Province (2014-114).

摘要: 为研究深厚淤泥质软土地基中开挖基坑时桩土间的作用机制,以江苏省长江沿岸某电厂锅炉房基坑开挖为背景,按1:50的相似比设计了室内离心模型试验,从桩身应变、桩身位移、桩顶位移、地表沉降、土体变形影响范围、桩身弯矩和孔隙水压力等方面,分析了基坑开挖对坑内已有基桩和周围土体的影响,并与现场基坑开挖出现的问题进行了对比分析。结果表明:对上部为淤泥质土,下伏较好土层的地基,当淤泥质土的抗剪强度相对较高时,开挖时基桩受力较大,容易出现断桩事故;开挖过程中基桩应变出现两处极值,深度分别在开挖深度附近和淤泥质土与下伏土层交界面附近;由于基桩的存在,靠近开挖面一侧的土体孔隙水压力变化平稳,而桩后土体孔隙水压力随着开挖的进行变化剧烈;基坑开挖后桩土之间的相互作用主要发生在开挖后48 h内,之后趋于稳定。试验结果与现场实测数据基本吻合,为深厚软土内基坑设计和施工过程提供了可借鉴的依据。

关键词: 深厚软土, 基坑开挖, 离心模型试验, 基桩变形, 桩土相互作用

Abstract: The foundation pit excavation of a power plant located along the Yangtze River in Jiangsu province is selected to study the interaction mechanism between piles and soils during excavation of foundation pits in deep silty soft soil. Thus an indoor centrifugal model test with the similarity ratio of 1:50 is designed. The influence of foundation pit excavation on existing pile and surrounding soil in deep silty soft soil are analyzed from different aspects including the pile strain, pile displacement, pile top displacement, surface settlement and soil deformation influence range, pile bending moment and pore water pressure. Results from the centrifugal test and the excavation of the foundation pit in situ are compared and analyzed. It shows that when the shear strength of silty soft soil in the upper part of the layered foundation is relatively high, the pile foundation is subjected to a large force and it is prone to the breakage accident during the excavation process. Two extreme values of pile strain occur near the excavation depth and the interface between the silty soil and the underlying soil layer. Due to the influence of the pile, the pore water pressure of the soil near the excavation face changes smoothly, but the pore water pressure of the soil after the pile changes drastically with the excavation. The interaction between piles and soils mainly lasts 48 hours after excavation before the restoration of stability. The test results match with the field measured data, which can provide a reference for the design and construction process of the foundation pit in deep and thick soft soil.

Key words: deep silty soft soil stratum, foundation pit excavation, centrifugal model test, foundation pile deformation, interaction between piles and soils

中图分类号: 

  • TU 47
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