上覆新填土软土深基坑开挖变形控制数值模拟

王龙; 朱长根; 徐柯锋; 俞剑; 吕玺琳

doi:10.11779/CJGE2021S2020

上覆新填土软土深基坑开挖变形控制数值模拟 English Version

王龙^{1, 2,},
朱长根³,
徐柯锋³,
俞剑^{1, 2},
吕玺琳^{1, 2, ,}

1.
同济大学岩土及地下工程教育部重点试验室,上海　200092
2.
同济大学地下建筑与工程系,上海　200092
3.
上海宝冶集团有限公司,上海　200941

基金项目:

国家重点研发计划项目 2016YFC0800200

详细信息

作者简介:
王龙(1994— ),男,硕士研究生,主要从事基坑工程方面研究工作。E-mail: 452195214@qq.com

通讯作者:
吕玺琳, E-mail: xilinlu@tongji.edu.cn

中图分类号: TU447
计量
- 文章访问数: 218
- HTML全文浏览量: 28
- PDF下载量: 227
出版历程
- 收稿日期: 2021-08-15
- 网络出版日期: 2022-12-05
- 刊出日期: 2021-10-31

Numerical simulation of deformation control during excavation of deep foundation pit in soft soil with newly filled soil

WANG Long^{1, 2,},
ZHU Chang-gen³,
XU Ke-feng³,
YU Jian^{1, 2},
LÜ Xi-lin^{1, 2, ,}

1.
Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China
2.
Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China
3.
Shanghai Baoye Group Co., Ltd., Shanghai 200941, China

摘要

摘要: 当存在上覆新填土条件下,深基坑开挖导致的变形规律值得重视。针对深圳某填土区线型深基坑开展有限元模拟,分析了不同围护桩插入比以及加固条件下坑底回弹变形和地表沉降的分布规律。结果表明,在土质软弱的新填土沿海软弱土地区,增加围护桩插入比虽能显著减少坑外地表沉降,但对于控制坑底隆起效果不佳；坑底土体被动区搅拌桩加固可显著减少坑底隆起和地表沉降,加固9 m深度时,坑底隆起和地表沉降可减少75%以上。
- 线型基坑 /
- 坑底隆起 /
- 地表沉降 /
- 数值模拟
Abstract: Under the overburden of newly filled soil, the deformation law of ground caused by excavation of foundation pits needs attention. Based on a linear deep foundation pit in the coastal Shenzhen-Hong Kong cooperation zone, the influences of different reinforcement plans and insertion ratios of retaining piles on the rebound deformation and surface settlement of the foundation pit are investigated through the finite element simulation. The conclusions can be drawn as follows: in the coastal soft soil areas with poor soil quality and newly filled soil, as the resistance to deformation in the passive areas is poor, the relevant measures should be taken to reduce the bottom uplift of pit and surface settlement deformation. Increasing the insertion ratio of retaining piles is not a useful way to control the uplift of pit bottom, but can significantly reduce the surface settlement outside the pit. Using the mixing piles to reinforce the passive areas of soil at the bottom of the pit can significantly reduce the uplift of the pit bottom and the surface settlement, and when the depth of reinforcement is 9 m, the uplift and surface settlement can be reduced by more than 75%.
- linear foundation pit /
- uplift of pit bottom /
- surface subsidence /
- numerical simulation

HTML全文

图 1 基坑剖面图

Figure 1. Profile of foundation pit

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图 2 基坑数值计算模型

Figure 2. Numerical model for foundation pit

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图 3 基坑不同开挖阶段示意图

Figure 3. Schematic diagram of excavation stage for foundation pit

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图 4 基坑不同开挖阶段地层变形

Figure 4. Ground deformations at different excavation stages

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图 5 围护插入比对地层变形的影响

Figure 5. Influences of enclosure insertion ratio on ground deformation

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图 6 基坑坑底隆起变形

Figure 6. Uplift deformations of bottom of foundation pit

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图 7 地表沉降

Figure 7. Ground deformations

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表 1 填土区线型深基坑地层土体模型参数

Table 1 Model parameters of soil of linear deep foundation pit in filling area

土层	$c^{'} / kPa$	$φ^{'} /$ (°)	$E_{oed}^{ref} / MPa$	$E_{50}^{ref} / MPa$	$E_{ur}^{ref} / MPa$	$G_{0} / MPa$	$γ_{0.7}$ /10^-4	m	$K_{0}$	$R_{f}$
人工填土	12	10	6.0	6.0	30.0	30.0	3.0	0.65	0.74	0.90
淤泥	10	8	—	—	—	—	—	—	—	—
黏土	20	18	5.1	5.0	31.0	96.0	3.0	0.65	0.69	0.90
砂质黏性土	22	20	3.9	3.2	24.5	67.5	3.0	0.65	0.66	0.90
全风化岩	25	30	4.5	4.5	30.0	67.5	3.0	0.65	0.50	0.90
强风化岩	30	35	3.9	3.9	24.5	67.5	3.0	0.65	0.43	0.90
加固土	60	25	15.0	15.0	85.0	170.0	20.0	0.50	0.50	0.95

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