基坑开挖及桩基施工对围护结构变形的影响分析
摘要:以北京通州某深基坑工程为例，分析基坑开挖卸荷、基坑锚杆施工、基底CFG桩和抗拔桩施工对基坑围护结构和周边环境的影响。结果表明：基坑围护结构及基坑周边地表随着基坑的开挖、围护锚索和基坑内工程桩的施工出现典型的先上浮后沉降的趋势，应力重新分布现象明显。具体表现为基坑开挖卸荷初期引发围护结构及基坑周边地表上浮，随着基坑开挖深度的增加，在基坑侧向位移和基坑锚索竖向分力作用下，围护结构及基坑周边地表开始下沉；在基坑槽底施工CFG桩和抗拔桩削弱了护坡桩嵌固区被动土压力，基坑降水导致土体有效应力增加，产生附加固结沉降，在基坑地下水渗流的联合作用下，围护结构及基坑周边地表呈现二次加速下沉；基坑开挖和基础桩施工对桩顶水平位移和锚索轴力影响较小。根据分析结果，建议类似基坑增加嵌固深度、调整被动土压力区打桩顺序，将有利于围护结构及基坑周边环境变形控制。
Abstract:A deep foundation pit in Tongzhou, Beijing was studied as an example, the effects on the foundation pit maintenance structure and the surrounding environment were discussed including foundation pit excavation and unloading, maintenance anchor construction, CFG, and uplift pile construction. The analysis results show that: the typical maintenance structure and the surrounding surface settlement of the foundation pit float first and then decrease with the excavation of the foundation pit, maintenance of anchor cable, and construction of pile foundation. The specific performance is that the excavation unloading of foundation pit will cause the maintenance structure and the surrounding surface floating; With the increase of the excavation depth of the foundation pit, the maintenance structure and the surrounding surface begin to sink under the condition of the lateral deformation of the foundation pit and the vertical component force of anchor cable; The construction of CFG and uplift pile in the foundation pit weakens the passive earth pressure in the embedded area of the slope protection pile, dewatering in the foundation pit leads to an increase in effective stress in the soil, resulting in additional consolidation settlement, under the combined action of groundwater seepage in the foundation pit, the maintenance structure and the surrounding surface show secondary accelerated subsidence; Foundation pit excavation and foundation pile construction have little effect on horizontal displacement of pile top and axial force of anchor cable. According to the analysis results, it is suggested that increasing the embedded depth of a similar foundation pit and adjusting the piling sequence of the passive earth pressure zone will be beneficial for deformation control of the maintenance structure and surrounding environment.
中文标题：
基坑开挖及桩基施工对围护结构变形的影响分析
Influence of Foundation Pit Excavation and Pile Foundation Construction on Maintenance Structure Deformation
作者：
刘青松,盛志战,王勇
Liu Qingsong,Sheng Zhizhan,Wang Yong
作者简介:刘青松，男，1982年生，汉族，河北栾城人，硕士，高级工程师，主要从事地基处理和基坑支护方面的工作。E-mail：lqscedar@163.com
通讯地址：
北京市勘察设计研究院有限公司，北京 100038
BGIEngineeringConsultantsLtd.,Beijing100038,China
中图分类号:TU 473
doi:10.3969/j.issn.1007-2993.2023.06.019
出版物：岩土工程技术
收稿日期:2022-12-24
修回日期:2023-05-31
录用日期:2023-07-14
刊出日期:2023-12-08
关键词:深基坑,应力释放,被动土压力区扰动,围护结构变形
Key words:deep foundation pit,stress release,disturbance in passive earth pressure zone,deformation of maintenance structure
文档包含图片数量：图片(7)张
文档包含表格数量：表格(2)个
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