坑内隔墙高度对基坑挖前抽水测试引发围挡偏转的影响

薛秀丽 杨瑶 曾超峰 李淼坤 陈秋南 龙四春 罗桂军

薛秀丽, 杨瑶, 曾超峰, 等. 2023. 坑内隔墙高度对基坑挖前抽水测试引发围挡偏转的影响[J]. 工程地质学报, 31(5): 1719-1727. doi: 10.13544/j.cnki.jeg.2022-0008
引用本文: 薛秀丽, 杨瑶, 曾超峰, 等. 2023. 坑内隔墙高度对基坑挖前抽水测试引发围挡偏转的影响[J]. 工程地质学报, 31(5): 1719-1727. doi: 10.13544/j.cnki.jeg.2022-0008
Xue Xiuli, Yang Yao, Zeng Chaofeng, et al. 2023. Effect of cross wall height on enclosure wall deflection incurred by pumping test before bulk excavation[J]. Journal of Engineering Geology, 31(5): 1719-1727. doi: 10.13544/j.cnki.jeg.2022-0008
Citation: Xue Xiuli, Yang Yao, Zeng Chaofeng, et al. 2023. Effect of cross wall height on enclosure wall deflection incurred by pumping test before bulk excavation[J]. Journal of Engineering Geology, 31(5): 1719-1727. doi: 10.13544/j.cnki.jeg.2022-0008

坑内隔墙高度对基坑挖前抽水测试引发围挡偏转的影响

doi: 10.13544/j.cnki.jeg.2022-0008
基金项目: 

国家自然科学基金项目 51978261

湖南省自然科学基金项目 2022JJ20023

湖南省科技创新计划项目 2022RC1172

详细信息
    作者简介:

    薛秀丽(1986-),女,博士,副教授,硕士生导师,主要从事岩土工程方面的科研与教学工作. E-mail: xlxue@hnust.edu.cn

    通讯作者:

    曾超峰(1987-),男,博士,教授,博士生导师,主要从事岩土工程与工程地质方面的科研与教学工作. E-mail: cfzeng@hnust.edu.cn

  • 中图分类号: TU473

EFFECT OF CROSS WALL HEIGHT ON ENCLOSURE WALL DEFLECTION INCURRED BY PUMPING TEST BEFORE BULK EXCAVATION

Funds: 

the National Natural Science Foundation of China 51978261

the Natural Science Foundation of Hunan Province 2022JJ20023

the Science and Technology Innovation Program of Hunan Province 2022RC1172

  • 摘要: 基坑挖前抽水可诱发明显围挡变形,而常用的墙顶支撑方案尚不能很好地防控围挡深部位置变形。近期,有学者针对软土地区基坑施工常用的“坑内布设隔墙的分区段施做方法”,提出了“考虑隔墙支护效应”及“优化布置隔墙”的变形防控理念,实现了基坑挖前抽水引发变形的有效控制。为进一步优化坑内隔墙的布置,本文开展了隔墙高度对挖前抽水引发变形的影响研究。针对某具体基坑工程,通过一系列数值分析,探究了在不同抽水深度、隔墙高度条件下挖前抽水引发的基坑围挡变形特性,并基此提出了隔墙在深度方向的优化布置方案。研究表明,隔墙在深度方向的布置范围对其变形控制效果有很大影响,具体地,在降水深度范围内布设隔墙可显著减小抽水引发的围挡侧移,而降水深度以下的隔墙布设对围护结构侧移的控制作用十分有限。为兼顾经济性与变形控制效果,建议将隔墙顶面设置在降水深度(Hd)以上0.33~0.67Hd位置处,隔墙底面设置在Hd处;但当坑外存在对变形敏感的深埋结构时,可将隔墙底面进一步向下延伸1/3Hf(Hf为降水深度至围护结构底面距离)以达到控制深埋结构变形的目的。
  • 图  1  曾超峰等(2021a, 2021b)提出的隔墙间距与内挑长度优化布置方案

    a. 平面图;b. A-A剖面图

    Figure  1.  Optimized layout of cross wall proposed by Zeng et al.(2021a,2021b)

    图  2  某地铁基坑平面

    Figure  2.  Plan view of a metro excavation

    图  3  模型Ⅰ的布置图

    Figure  3.  Layout of Model Ⅰ

    图  4  测斜孔C1和C3处侧移计算与实测值对比

    Figure  4.  Comparison between computed and observed wall deflection at C1 and C3

    图  5  基坑围挡-坑内隔墙的模型布置

    Figure  5.  Layout of enclosure wall and inner cross wall in the model

    图  6  隔墙位置处基坑剖面图

    Figure  6.  Cross section of the pit at the location of the cross wall

    图  7  不同hc1条件下基坑围挡顶部变形水平分布

    Figure  7.  Distribution of enclosure wall deflection on wall crown along the horizontal direction under different hc1

    a. Hd=11 m; b. Hd=21.5 m

    图  8  不同hc1条件下隔墙处基坑围挡变形竖向分布

    Figure  8.  Distribution of enclosure wall deformation along depth under different hc1

    a. Hd=11 m; b. Hd=21.5 m

    图  9  δhc1hc1/Hd变化曲线

    Figure  9.  δhc1 vs. hc1/Hd

    图  10  δhc1/δhc1,maxhc1/Hd关系曲线

    Figure  10.  δhc1hc1,max vs. hc1/Hd

    图  11  不同hc2条件下基坑围挡顶部变形的水平分布

    Figure  11.  Distribution of enclosure wall deflection on wall crown along horizontal direction under different hc2

    a. hc1/Hd=0; b. hc1/Hd=1

    图  12  不同hc2条件下横隔墙位置处基坑围挡变形的竖向分布

    Figure  12.  Distribution of enclosure wall deformation along depth under different hc2

    a. Hd=11 m; b. Hd=21.5 m

    图  13  δhc2hc2/Hf变化曲线

    Figure  13.  δhc2 vs. hc2/Hf

    图  14  δhc2/δhc2,maxhc2/Hf关系曲线

    Figure  14.  δhc2hc2,max vs. hc2/Hf

    表  1  各土层修正剑桥模型计算参数

    Table  1.   Calculation parameters of each soil used in the Modified Cam-Clay model

    土的类型 层底埋深/m λ κ M γ/kN·m-3 e kv/m·d-1 kh/m·d-1 K0
    粉质黏土 5.5 0.0553 0.0065 0.979 19.35 0.811 0.1 0.1 0.49
    黏质粉土 11.0 0.0312 0.0036 1.192 19.30 0.792 0.5 0.5 0.43
    粉质黏土 19.0 0.0445 0.0052 0.979 20.10 0.696 1×10-4 5×10-4 0.50
    砂质粉土 24.0 0.0293 0.0034 1.202 20.15 0.640 1 1 0.42
    黏土 27.0 0.0397 0.0046 0.800 19.75 0.764 1×10-5 5×10-5 0.55
    砂质粉土 33.0 0.0283 0.0033 1.202 20.65 0.583 0.7 1 0.35
    粉质黏土 37.0 0.0320 0.0037 0.900 20.50 0.611 3×10-4 5×10-4 0.39
    粉、细砂 42.0 0.0191 0.0022 1.382 20.50 0.585 1.5 2.5 0.30
    粉质黏土 50.0 0.0305 0.0035 0.900 19.30 0.864 2×10-4 5×10-4 0.39
    下载: 导出CSV

    表  2  模型计算工况参数取值表

    Table  2.   Parameter values used in different calculation conditions

    Hd/m hc1/Hd(hc2/Hf) hc1/m hc2/m
    11 0 0 0
    1/3 4 7
    2/3 8 14
    1 11 22
    16 0 0 0
    1/3 5 6
    2/3 10 12
    1 16 17
    19 0 0 0
    1/3 6 5
    2/3 12 10
    1 19 14
    21.5 0 0 0
    1/3 7 4
    2/3 14 8
    1 22 11
    下载: 导出CSV
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出版历程
  • 收稿日期:  2022-01-05
  • 修回日期:  2022-02-18
  • 刊出日期:  2023-10-25

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