软土基坑宽度效应对坑底隆起的影响
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摘要
通过对宽大型软土基坑坑底隆起特性及形成机理分析,将坑底土体划分成强作用区、弱作用区和自由变形区,提出综合考虑基坑开挖深度、围护结构插入比和土体性质的强、弱作用区边界计算方法;根据基坑开挖宽度不同时,坑底隆起作用区的变化情况,提出考虑坑底隆起宽度效应的基坑分类方法:将基坑划分为超大尺度基坑、大尺度基坑、小尺度基坑和沟槽类基坑4类,并明确各类基坑的宽度范围。最后结合上海某软土基坑工程实例,采用有限元法数值分析对本文提出的理论分类方法的正确性进行了验证。
Through analyzing characteristics and forming mechanism of basal heave of the wide excavation in soft soil, by dividing basal soil mass into strong interacting region, weak interacting region and free deformation region, this paper puts forward a computing method of boundary length for different heave areas considering the excavation depth, embedment depth and soil properties. Then the foundation pits classification method considering the width effect is presented. In terms of transformation of each region in the process of excavation width change, excavation can be classified into extra-large scale excavation, large scale excavation, small scale excavation and trenches, whose width area of different foundation pits is given. The validity of this classification system is verified by FEM method combined with an excavation project in Shanghai.
Through analyzing characteristics and forming mechanism of basal heave of the wide excavation in soft soil, by dividing basal soil mass into strong interacting region, weak interacting region and free deformation region, this paper puts forward a computing method of boundary length for different heave areas considering the excavation depth, embedment depth and soil properties. Then the foundation pits classification method considering the width effect is presented. In terms of transformation of each region in the process of excavation width change, excavation can be classified into extra-large scale excavation, large scale excavation, small scale excavation and trenches, whose width area of different foundation pits is given. The validity of this classification system is verified by FEM method combined with an excavation project in Shanghai.
引文
[1]同济大学.多重组合式基坑群施工相互影响及应对措施研究[R].上海:同济大学,2012
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[3]李淑,张顶立,房倩,等.北京地铁车站深基坑地表变形特性研究[J].岩石力学与工程学报,2012,31(1):189-198.
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[5]王步翔,曹雪山.狭长深基坑支护结构设计的有限元分析[J].华东交通大学学报,2015,32(1):65-770.
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[8]张雷,刘振宏,钱元运,等.深基坑宽度对周围建筑影响的有限元分析[J].地下空间与工程学报,2009,5(S):1312-1344.
[9]王洪新,孙玉永.考虑基坑开挖宽度的杆系有限元算法及试验研究[J].岩土力学,2012,33(9):2781-2787.
[10]王洪新,周松.基坑设计的杆系-荷载-弹簧模型荷载取值及变形和稳定性分析的若干问题和研究建议[J].岩土力学与工程学报,2013,32(11):2349-2358.
[11]王洪新.基坑宽度对围护结构稳定性的影响[J].土木工程学报,2011,44(6):120-126.
[12]周顺华.开挖理论[M].北京:中国铁道出版社,1997.
[13]刘国彬,王卫东.基坑工程手册[M].2版.北京:中国建筑工业出版社,2009.
[14]夏明耀.地下连续墙的变形机理与环境问题对策[J].同济大学学报,1991,19(1):59-66.
[15]贾坚,谢小林.上海软土地区深大基坑卸荷变形机理[J].上海交通大学学报,2009,43(6):1005-1010.
[16]汪炳鉴,夏明耀.地下连续墙的墙体内力及入土深度问题[J].岩土工程学报,1983,5(3):103-114.
[17]王洪新.对基坑抗隆起稳定安全系数的改进[J].岩土力学,2014,35(S2):30-36.
[18]中华人民共和国国家标准.建筑边坡工程技术规范(GB50330-2002)[S].北京:中国建筑工业出版.
[2]王旭军.上海中心大厦裙房深大基坑变形特性及盆式开挖技术研究[D].上海:同济大学,2014.
[3]李淑,张顶立,房倩,等.北京地铁车站深基坑地表变形特性研究[J].岩石力学与工程学报,2012,31(1):189-198.
[4]李岩松,邹吉聪.上海自然博物馆基坑地下连续墙变形研究[J].华东交通大学学报,2012,29(2):51-56,107.
[5]王步翔,曹雪山.狭长深基坑支护结构设计的有限元分析[J].华东交通大学学报,2015,32(1):65-770.
[6]BOSE S K,SOM N N.Parametric study of a braced cut by finite element method[J].Computers and Geotechnics,1998,22(2):91-107.
[7]KUNG G T,JUANG C H,HSIAO E C L,et al.Simplified model for wall deflection and ground-surface settlement caused by braced excavation in clay[J].Journal of Geotechnical and Geoenvironmental Engineering,2007,133(6):731-747.
[8]张雷,刘振宏,钱元运,等.深基坑宽度对周围建筑影响的有限元分析[J].地下空间与工程学报,2009,5(S):1312-1344.
[9]王洪新,孙玉永.考虑基坑开挖宽度的杆系有限元算法及试验研究[J].岩土力学,2012,33(9):2781-2787.
[10]王洪新,周松.基坑设计的杆系-荷载-弹簧模型荷载取值及变形和稳定性分析的若干问题和研究建议[J].岩土力学与工程学报,2013,32(11):2349-2358.
[11]王洪新.基坑宽度对围护结构稳定性的影响[J].土木工程学报,2011,44(6):120-126.
[12]周顺华.开挖理论[M].北京:中国铁道出版社,1997.
[13]刘国彬,王卫东.基坑工程手册[M].2版.北京:中国建筑工业出版社,2009.
[14]夏明耀.地下连续墙的变形机理与环境问题对策[J].同济大学学报,1991,19(1):59-66.
[15]贾坚,谢小林.上海软土地区深大基坑卸荷变形机理[J].上海交通大学学报,2009,43(6):1005-1010.
[16]汪炳鉴,夏明耀.地下连续墙的墙体内力及入土深度问题[J].岩土工程学报,1983,5(3):103-114.
[17]王洪新.对基坑抗隆起稳定安全系数的改进[J].岩土力学,2014,35(S2):30-36.
[18]中华人民共和国国家标准.建筑边坡工程技术规范(GB50330-2002)[S].北京:中国建筑工业出版.