上海交通大学学报 ›› 2022, Vol. 56 ›› Issue (4): 454-463.doi: 10.16183/j.cnki.jsjtu.2021.036

• 船舶海洋与建筑工程 • 上一篇    下一篇

地铁变频荷载循环作用下饱和软黏土累积塑性变形

李泽垚1, 周洁1(), 田万君2, 裴万胜3   

  1. 1.同济大学 地下建筑与工程系, 上海 200092
    2.中国建筑第二工程局有限公司,北京 100054
    3.中国科学院 西北生态环境资源研究院 冻土工程国家重点实验室,兰州 730000
  • 收稿日期:2021-01-25 出版日期:2022-04-28 发布日期:2022-05-07
  • 通讯作者: 周洁 E-mail:15050@tongji.edu.cn
  • 作者简介:李泽垚(1994-),男,河北省石家庄市人,博士生,从事地铁隧道及联络通道施工等方面的研究工作.
  • 基金资助:
    国家自然科学基金(41702299);冻土工程国家重点实验室开放基金(SKLFSE201916)

Accumulative Plastic Deformation of Saturated Soft Clay Under Variable Frequency Cyclic Loading for Subway

LI Zeyao1, ZHOU Jie1(), TIAN Wanjun2, PEI Wansheng3   

  1. 1. Department of Geotechnical Civil Engineering, Tongji University, Shanghai 200092, China
    2. China Construction Second Engineering Bureau Co., Ltd., Beijing 100054, China
    3. State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment andResources, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2021-01-25 Online:2022-04-28 Published:2022-05-07
  • Contact: ZHOU Jie E-mail:15050@tongji.edu.cn

摘要:

地铁在地铁站附近的加减速运动会对地基土产生一定的影响.土体经过倾斜削样后使用动三轴进行不排水动力测试以研究地铁进出站作用下进出站距离、加速度、动应力幅值及固结围压对饱和软黏土累积塑性变形的影响.结果表明:进出站变频荷载循环作用下软黏土累积塑性应变曲线可大致划分为爆发增长-较快增长-逐渐稳定3个阶段.距地铁站越近、动应力幅值越大、固结围压越小,土体进入逐渐稳定阶段所需的进出站次数越少,土体竖向变形越大,剪切变形越小.进出站加速度值越大,土体竖向变形越小、剪切变形越大.对于实际工程而言,地铁运营初期,进站区间土体的沉降变形、出站区间土体水平位移、较大加速度工况下的水平位移、较小加速度工况下的沉降、高动应力幅值的工况及低固结应力的土体区域是工程地质灾害防治的重点.

关键词: 地下工程, 变频循环荷载, 加速度, 累积变形, 不排水动三轴试验, 软黏土

Abstract:

The acceleration and deceleration movement of the metro near the metro station have a certain impact on the foundation soil. After the soil has been sloped and sampled, a dynamic three-axis undrained dynamic test is conducted to study the influence of the distance of the metro station, acceleration, dynamic stress amplitude, and consolidation confining pressure on the cumulative plastic deformation of saturated soft clay. The results show that the cumulative plastic strain curve of soft clay at variable frequency cyclic loading in and out of the station can be roughly divided into three stages: explosive growth, rapid growth, and gradual stability. The increase in the distance from the metro station, the increase in the amplitude of the dynamic stress, and the decrease in the consolidation confining pressure can reduce the number of entry and exit times required for the soil to enter the gradual stabilization phase, increase the vertical deformation of the soil, and reduce the shear deformation. As the acceleration value in and out of the station increases, the vertical deformation of the soil decreases but the shear deformation increases. For the actual project, the initial stage of metro operation, the settlement deformation of the soil in the inbound section, the horizontal displacement of the soil in the outbound section, the horizontal displacement under the larger acceleration condition, the settlement under the smaller acceleration condition, the high dynamic stress amplitude, and the soil area with a low consolidation stress are the focus of engineering geological disaster prevention.

Key words: underground engineering, variable frequency cyclic load, acceleration, cumulative deformation, undrained dynamic triaxial test, soft clay

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