Engineering Practice of Large Area Shallow Foundation Pit Support in Distribution Area of Shallow Buried Thick Silty Soil
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摘要: 浅部厚层粉性土分布区的浅基坑工程，由于围护体系不能有效隔断含水层，致使基坑坑内降水具有三维渗流特性，当土质较差或周边环境复杂时，基坑设计与施工将面临严峻挑战。以上海市崇明区某大面积浅基坑工程为例，探讨了基坑降水与围护结构体系在基坑安全方面的相互关系，据此推出将基坑围护结构、止水帷幕与基坑降水统筹考虑的一体化设计思路。介绍了围护结构、降水管井及悬挂式止水帷幕深度确定的方法和依据，强调了围护方案技术交底的重要性。基坑开挖及监测数据表明，采用悬挂式止水帷幕+坑内管井降水结合放坡或重力式挡墙进行基坑地下水控制与围护的方案是可行的，能够取得良好的工程效果。Abstract: Due to the fact that enclosure system of shallow foundation pit engineering can not isolate the water-bearing layer effectively in distribution area of shallow buried thick silty soil, the dewatering inside foundation pit shows the characteristic of three-dimensional seepage, and the design and construction of foundation pit face severe challenges especially when the soil quality is poor or the surrounding environment is complex. Taking a large-area shallow foundation pit engineering in Chongming District of Shanghai as an example, the relationship between foundation pit dewatering and enclosure structure system on the safety of foundation pit were discussed. The integrated design idea which considers enclosure structure system of foundation pit, water-stopping curtain and foundation pit dewatering as a whole was put forward. The calculation method and basis on the depth of enclosure structure, tube well and suspended impervious curtain were introduced, and the importance of technical tests on foundation pit supporting plan was emphasized. Foundation pit excavation and monitoring data showed that it is feasible and effective to adopt the scheme of suspended impervious curtain, tube well dewatering inside foundation pit and slope or gravity retaining wall for supporting foundation pit and controlling groundwater.
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Key words:
- silty soil /
- foundation pit support /
- water-resisting curtain /
- foundation pit dewatering
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表 1 土层物理力学性质综合成果表
层号 土层名称 层底平均标高/m 重度γ0 /(kN·m−3) 黏聚力c/kPa 内摩擦角φ/(°) kv/(cm·s−1) kh/(cm·s−1) ②1 粉质黏土夹粉土 1.56 18.5 17 19.0 3.49E-06 1.12E-05 ②2 淤泥质粉质黏土夹粉土 1.46 17.9 13 19.5 3.18E-06 1.11E-05 ②3-1 黏质粉土 1.35 18.6 6 27.0 3.52E-05 1.29E-04 ②3-2 砂质粉土 −5.52 18.8 2 32.5 4.68E-04 6.04E-04 ②3-3 砂质粉土夹粉质黏土 −11.53 18.5 6 26.0 1.34E-04 2.44E-04 ②3-4 砂质粉土 −13.80 18.8 2 31.5 3.87E-04 5.46E-04 ②3-5 砂质粉土夹粉质黏土 −16.00 18.5 7 26.8 1.74E-05 3.96E-05 ④ 淤泥质黏土 −15.99 16.9 13 10.5 8.40E-08 3.3E-07 注：表中c、φ值均采用勘察报告提供的固结快剪峰值指标；kv、kh值为勘察报告提供的室内渗透系数指标。 
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[1] 黄鑫磊. 基于地面沉降控制的基坑围护与工程降水一体化设计方法与应用[J]. 上海国土资源,2018,39(4):122-125. doi: 10.3969/j.issn.2095-1329.2018.04.026 [2] 张钦喜,宁亚通,闫金波,等. 悬挂式止水帷幕涌水量计算数值模拟及验证[J]. 岩土工程技术,2021,35(4):255-259. doi: 10.3969/j.issn.1007-2993.2021.04.009 [3] 张 兴. 抽水试验及数值模拟在基坑工程中的应用[J]. 岩土工程技术,2021,35(5):306-311. doi: 10.3969/j.issn.1007-2993.2021.05.005 [4] 瞿成松,张国强,罗建军,等. 上海中心大厦基坑降水及实践[J]. 资源环境与工程,2011,25(3):209-214. doi: 10.3969/j.issn.1671-1211.2011.03.008 [5] 瞿成松. 上海地铁四号线董家渡修复段基坑降水实录[J]. 岩土工程学报,2010,32(S2):339-342. [6] 唐益群, 周 洁, 杨 坪, 等. 工程地下水(第二版)[M]. 上海: 同济大学出版社, 2020. [7] 龚晓南, 侯伟生. 深基坑工程设计施工手册(第二版)[M]. 北京: 中国建筑工业出版社, 2018. [8] 吴林高, 李 国, 方兆昌, 等. 基坑工程降水案例[M]. 北京: 人民交通出版社, 2009. [9] 吴林高, 等. 工程降水设计施工与基坑涌渗流理论 [M]. 北京: 人民交通出版社, 2003. [10] 姚天强, 石振华, 曹惠宾, 等. 基坑降水手册[M]. 北京: 中国建筑工业出版社, 2006. [11] 刘国彬, 王卫东. 基坑工程手册(第二版)[M]. 北京: 中国建筑出版社, 2009. [12] 上海市工程建设规范. DG/TJ 08—61—2018 基坑工程技术标准[S]. -
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