超大荷载下CFG桩网复合地基离心模型试验研究

    王年香, 周春儿, 董华钢, 李珍, 何元瑭

    王年香, 周春儿, 董华钢, 李珍, 何元瑭. 超大荷载下CFG桩网复合地基离心模型试验研究[J]. 岩土工程学报, 2022, 44(S2): 87-91. DOI: 10.11779/CJGE2022S2019
    引用本文: 王年香, 周春儿, 董华钢, 李珍, 何元瑭. 超大荷载下CFG桩网复合地基离心模型试验研究[J]. 岩土工程学报, 2022, 44(S2): 87-91. DOI: 10.11779/CJGE2022S2019
    WANG Nian-xiang, ZHOU Chun-er, DONG Hua-gang, LI Zhen, HE Yuan-tang. Centrifugal model tests on CFG pile-net composite foundation under super-large loads[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(S2): 87-91. DOI: 10.11779/CJGE2022S2019
    Citation: WANG Nian-xiang, ZHOU Chun-er, DONG Hua-gang, LI Zhen, HE Yuan-tang. Centrifugal model tests on CFG pile-net composite foundation under super-large loads[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(S2): 87-91. DOI: 10.11779/CJGE2022S2019

    超大荷载下CFG桩网复合地基离心模型试验研究  English Version

    基金项目: 

    中央级公益性科研院所基本科研业务费专项资金项目 Y321006

    中央级公益性科研院所基本科研业务费专项资金项目 Y321007

    详细信息
      作者简介:

      王年香(1963—),男,江西信丰人,博士,正高级工程师,博士生导师,主要从事岩土工程基本理论和试验研究工作。E-mail: nxwang@nhri.cn

    • 中图分类号: TU435

    Centrifugal model tests on CFG pile-net composite foundation under super-large loads

    • 摘要: CFG桩网复合地基广泛应用于处理软土地基。采用土工离心模型试验研究某码头堆场超大荷载下CFG桩网复合地基的变形和桩土应力特性,试验模拟了地基、CFG桩、树根桩、加筋垫层、防尘网和轨道梁基础、矿石堆载等,分析了超大荷载作用下复合地基表面变形、孔隙水压力、桩顶轴力、桩土应力比的变化规律。试验结果表明,复合地基的沉降速率在稳定控制标准之内,沉降量满足堆场使用要求,防尘网基础和轨道梁基础水平位移和沉降均很小,桩土应力比20~36。典型区CFG桩网复合地基在350 kPa荷载作用下是稳定安全的,达到了预期加固效果。
      Abstract: CFG pile-net composite foundation is widely used to reinforce soft soil foundation. Geotechnical centrifuge model test was carried out to study the deformation and pile-soil stress characteristics of CFG pile-net composite foundation under super large load in the storage yard of a wharf. The foundation, CFG piles, root piles, reinforced cushions, dust nets, track beam foundation and ore loads are simulated. The variation laws of the surface deformations, pore water pressures and loads at the top of the CFG piles and the pile-soil stress ratio of the composite foundation are analyzed under super-large loads. The settlement rate of the composite foundation is within the stability control standard, and the settlement meets the requirements of the storage yard. The horizontal displacements and settlements of the dust net foundation and the track beam foundation are small. The pile-soil stress ratio is 20~36. The test results show that the CFG pile-net composite foundation in the typical zone is stable and safe under the load of 350 kPa, and the foundation reinforcement has achieved the expected effects.
    • 图  1   复合地基剖面图

      Figure  1.   Profile of composite foundation

      图  2   离心模型试验布置图

      Figure  2.   Layout of centrifugal model tests

      图  3   复合地基表面沉降过程线

      Figure  3.   Surface settlement-time curves of composite foundation

      图  4   复合地基孔隙水压力增长和消散过程线

      Figure  4.   Pore water pressure-time curves of composite foundation

      图  5   复合地基CFG桩桩顶轴力过程线

      Figure  5.   Load-time curves at top of CFG piles

      表  1   土的物理力学性质指标

      Table  1   Physical and mechanical properties of soils

      土名 厚度/m 含水率/% 密度/(g·cm-3) 不排水强度/kPa
      素填土①2 2.48 32.0 1.91 25
      淤泥质黏土②1 6.20 50.8 1.72 31
      粉质黏土③4 3.50 31.0 1.92 41
      中粗砂③2 1.70 1.85
      黏土④1、④2 42.3 1.77 51
      下载: 导出CSV

      表  2   复合地基表面变形特征值

      Table  2   Surface deformations of composite foundation (mm)

      测点 时间节点
      堆载期 试堆期 恒载365 d 恒载408 d
      沉降 Sa1 -22 -9 39 42
      Sa2 50 82 175 181
      Sa3 139 210 399 411
      Sa4 149 208 366 375
      Sa5 -20 -2 71 76
      水平位移 Db1 -4 -9 -28 -30
      Db5 0 11 44 45
      下载: 导出CSV

      表  3   复合地基孔隙水压力特征值

      Table  3   Pore water pressures of composite foundation

      时间节点 测点
      U1 U4
      孔压/kPa 孔压系数 孔压/kPa 孔压系数
      堆载期 27 0.08 117 0.34
      试堆期 48 0.14 180 0.51
      峰值 50 0.14 205 0.59
      (恒载32 d) (恒载85 d)
      恒载365 d 33 0.09 198 0.57
      恒载408 d 32 0.09 197 0.56
      下载: 导出CSV

      表  4   复合地基CFG桩顶轴力特征值

      Table  4   Loads at top of CFG piles

      测点 Tf1 Tf2 Tf3 Tf4
      桩长、间距/m 10,1.8 14,1.8 16,1.8 16,1.65
      上覆荷载/kPa 150 232 319 350
      轴力/
      kN
      堆载期 184 344 539 543
      试堆期 185 349 522 528
      恒载365 d 190 354 475 496
      恒载408 d 191 353 474 495
      下载: 导出CSV

      表  5   复合地基桩土应力比特征值

      Table  5   Pile-soil stress ratios of composite foundation

      测点 Tf1 Tf2 Tf3 Tf4
      堆载期 桩身应力/MPa 1.92 3.58 5.61 5.66
      桩间土压力/kPa 96 130 157 156
      桩土应力比 20 28 36 36
      恒载408 d 桩身应力/MPa 1.99 3.68 4.94 5.16
      桩间土压力/kPa 94 127 178 174
      桩土应力比 21 29 28 29
      下载: 导出CSV
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    出版历程
    • 收稿日期:  2022-11-30
    • 网络出版日期:  2023-03-26
    • 刊出日期:  2022-11-30

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