带状堆载对邻近桩基作用效应的计算方法
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摘要
为研究路基等带状堆载对邻近桥梁桩基础受力影响的计算方法,基于Terzaghi地基承载力公式,将地表的带状堆载等效为埋深为0的条形基础荷载,根据承载力计算公式中地基土整体剪切破坏时的滑动面形状,采用极限平衡法,得到保证地基稳定的最大堆载高度以及带状堆载主要影响区的计算公式;判断带状堆载邻近桩基础是否受堆载影响,并得到带状堆载作用下地基土体侧移变形的计算深度及对邻近桩基础的推力计算公式,将上述作用效应施加到堆载邻近的桩基础上,使堆载作用下邻近桩基础受力模型简化为一般的被动受荷桩,采用m法计算了桩身效应。同时,建立带状堆载与邻近桩基础相互作用的有限元模型,分析堆载规模对邻近桩基变形特性的影响,并将理论计算结果与有限元结果进行比对。研究结果表明:堆载作用下地基土体浅层一定深度内发生了侧移变形,推挤邻近桩基而发生不同程度的挠曲,堆载作用下地基土体侧移存在影响深度范围;带状堆载作用对邻近桩基础的受力变形存在主要影响区,在该距离范围内堆载对桩基础影响明显,超过该范围后其影响并不消失,而是维持在较低水平;理论计算和有限元计算结果反映的规律基本一致,理论结果比有限元结果略保守,研究可为类似工程提供借鉴。
In order to analyze the calculation method of the influence of banding surcharge loads on the mechanical characteristics of adjacent pile foundation. The surcharge loads on the ground surface were considered equivalent to the strip foundation load with 0 m depth, based on the formula of Terzaghi's foundation bearing capacity. According to the sliding surface range of general shear failure in Terzaghi's formula, the limit equilibrium method was used to derive the maximum surcharge height formula. This ensures the stability of the foundation and the scope of influence of the formula under the impact of banding surcharge loads that provide the discriminant conditions to determine the effect of surcharge loads on the adjacent pile foundation. The depth range and soil pressure formula under lateral displacement of foundation soil was obtained. The above-mentioned mechanical effects were then applied to the pile foundation adjacent to the surcharge loads. The mechanical model of this pile foundation was simplified as the general passive pile. The pile response was calculated using the m method. The finite element model of the interaction between the surcharge loads and adjacent pile foundation was established to analyze the influence of surcharge load scale on the deformation characteristics of the adjacent pile. The result theoretical formula were compared with that of finite element results. The results show that the soil under surcharge loads is laterally deformed and the adjacent pile foundation is deflected in different degrees. Certain depth range and a primary influence zone are observed in the characteristics of lateral deformation of the soil under the surcharge loads. The effect of surcharge loads on the pile foundation is evident in this distance range. It is maintained at a low level instead of disappearing over this range. The theoretical and finite element calculations exhibit similar rules. However, the theoretical results are slightly conservative than the results of finite element. This study provides reference for similar projects.
In order to analyze the calculation method of the influence of banding surcharge loads on the mechanical characteristics of adjacent pile foundation. The surcharge loads on the ground surface were considered equivalent to the strip foundation load with 0 m depth, based on the formula of Terzaghi's foundation bearing capacity. According to the sliding surface range of general shear failure in Terzaghi's formula, the limit equilibrium method was used to derive the maximum surcharge height formula. This ensures the stability of the foundation and the scope of influence of the formula under the impact of banding surcharge loads that provide the discriminant conditions to determine the effect of surcharge loads on the adjacent pile foundation. The depth range and soil pressure formula under lateral displacement of foundation soil was obtained. The above-mentioned mechanical effects were then applied to the pile foundation adjacent to the surcharge loads. The mechanical model of this pile foundation was simplified as the general passive pile. The pile response was calculated using the m method. The finite element model of the interaction between the surcharge loads and adjacent pile foundation was established to analyze the influence of surcharge load scale on the deformation characteristics of the adjacent pile. The result theoretical formula were compared with that of finite element results. The results show that the soil under surcharge loads is laterally deformed and the adjacent pile foundation is deflected in different degrees. Certain depth range and a primary influence zone are observed in the characteristics of lateral deformation of the soil under the surcharge loads. The effect of surcharge loads on the pile foundation is evident in this distance range. It is maintained at a low level instead of disappearing over this range. The theoretical and finite element calculations exhibit similar rules. However, the theoretical results are slightly conservative than the results of finite element. This study provides reference for similar projects.
引文
[1] 冯忠居,张永清,李晋.堆载引起桥梁墩台与基础的偏移及防治技术研究[J].中国公路学报,2004,17(3):74-77. FENG Zhong-ju,ZHANG Yong-qing,LI Jin.Study of displacement of bridge pier and abutment foundation caused by earth piling load and its prevention technique[J].China Journal of Highway and Transport,2004,17(3):77-80.
[2] 冯忠居.特殊地区基础工程[M].北京:人民交通出版社,2008. FENG Zhong-ju.Foundation engineering in special areas[M].Beijing:China Communications Press,2008.
[3] DE BEER E E.The effects of horizontal loads on piles,due to surcharge or seismic effects[C]//ICSMFE.The Ninth Conference on Soil Mechanics and Foundation International Engineering.London:ICSMFE,1977:547-558.
[4] ELLIS E A,SPRINGMAN S M.Modelling of soil-structure interaction for a piled bridge abutment in plane strain FEM analyses[J].Computers and Geotechnics,2001,28(2):79-98.
[5] 陈福全,杨敏.地面堆载作用下邻近桩基性状的数值分析[J].岩土工程学报,2005,27(11):1286-1290. CHEN Fu-quan,YANG Min.Numerical analysis of piles influenced by lateral soil movement due to surcharge loads[J].Chinese Journal of Geotechnical Engineering,2005,27(11):1286-1290.
[6] 聂如松,冷伍明,杨奇,等.路基填土对桥台桩基影响的试验与数值仿真分析[J].岩土力学,2009,30(9):2862-2868. NIE Ru-song,LENG Wu-ming,YANG Qi,et al.Field test and 3D FEM studies of bridge abutment on piled foundation subjected to embankment load[J].Rock and Soil Mechanics,2009,30(9):2862-2868.
[7] MUTHUKKUMARAN K,KRISHNAN M G.Three dimensional analysis of piles on sloping ground subjected to passive load induced by surcharge[J].International Journal of Engineering and Technology Innovation,2012,2(1):31-47.
[8] KARIM M R.Behaviour of piles subjected to passive subsoil movement due to embankment construction-A simplified 3D analysis[J].Computers and Geotechnics,2013,53:1-8.
[9] 李志伟.软土地基邻近堆载对桥梁桩基偏位的影响研究[J].岩土力学,2013,34(12):3594-3600. LI Zhi-wei.Study of influence of surcharge load on lateral displacement of bridge piled foundation in soft ground[J].Rock and Soil Mechanics,2013,34(12):3594-3600.
[10] 李志伟.软土地基不对称堆载对桥梁偏位的影响及加固分析[J].公路,2016(8):86-92. LI Zhi-wei.Analysis of the influence of asymmetric load on deflection of bride and reinforcement in soft ground[J].Highway,2016(8):86-92.
[11] 董亮,牛斌,谷牧,等.大面积单侧堆载对高速铁路桥梁墩台影响的数值分析[J].铁道建筑,2015(1):39-42. DONG Liang,NIU Bin,GU Mu,et al.Numerical analysis on influence of large-area one-side surcharge load on abutments and piers of high speed railway bridges[J].Railway Engineering,2015(1):39-42.
[12] 邵曼.软土地区堆载对邻近高架桥墩的影响分析[J].公路工程,2016,41(3):212-215. SHAO Man.Numerical analysis on influence of pit excavation on adjacent bridge capped piles group[J].Highway Engineering,2016,41(3):212-215.
[13] 冯君,张俊云,朱明,等.软土地层高承台桥梁群桩基础横向承载特性研究[J].岩土力学,2016,37(增2):94-104. FENG Jun,ZHANG Jun-yun,ZHU Ming,et al.Characteristic study of horizontal bearing capacity and pile group effect coefficient of laterally loaded high pile group foundation for bridge in soft soil[J].Rock and Soil Mechanics,2016,37(S2):94-104.
[14] 聂如松,冷伍明,魏丽敏,等.堆载对既有桥墩桩基础影响距离分析[J].水文地质工程地质,2017,44(1):64-70. NIE Ru-song,LENG Wu-ming,WEI Li-min,et al.An analysis of the distance between surcharge load and existing bridged pile foundation in soft clay[J].Hydrogeology & Engineering Geology,2017,44(1):64-70.
[15] BRANSBY M F,SPRINGMAN S M.3-D finite element modelling of pile groups adjacent to surcharge loads[J].Computers and Geotechnics,1996,19(4):301-324.
[16] BRANSBY M F,SPRINGMAN S M.Centrifuge modelling of pile groups adjacent to surcharge loads[J].Soils and Foundations,1997,37(2):39-49.
[17] SPRINGMAN S M,BOLTON M D.The effect of surcharge loading adjacent to piles[R].Washington DC:Transport and Road Research Laboratory,1990.
[18] 陈雪华,律文田,王永和.台后填土对桥台桩基的影响分析[J].岩土工程学报,2006,28(7):910-913. CHEN Xue-hua,LU Wen-tian,WANG Yong-he.In-situ test of negative friction of abutment piles in soft soil[J].Chinese Journal of Geotechnical Engineering,2006,28(7):910-913.
[19] 丁任盛.临近堆载对深厚软土桩基影响的现场试验研究[J].铁道科学与工程学报,2015,12(2):291-296. DING Ren-sheng.Field test study on pile foundation subjected to adjacent surcharge in deep-soft soil strata[J].Journal of Railway Science and Engineering,2015,12(2):291-296.
[20] WANG L Z,CHEN K X,HONG Y,et al.Effect of consolidation on responses of a single pile subjected to lateral soil movement[J].Canadian Geotechnical Journal,2014,52(6):769-782.
[21] 李忠诚,梁志荣.大面积堆载土体侧移模式及对邻近被动桩影响分析[J].岩土工程学报,2010,32(增1):128-134. LI Zhong-cheng,LIANG Zhi-rong.Calculation model and numerical analysis of passive piles subjected to adjacent surcharge loads[J].Chinese Journal of Geotechnical Engineering,2010,32(S1):128-134.
[22] 冯昌明,木林隆,孙志伟,等.基于两阶段法的堆载对公路桥梁桩基础影响分析[J].岩土力学,2014,35(增2):528-534. FENG Chang-ming,MU Lin-long,SUN Zhi-wei,et al.Two-stage analysis of responses of bridge pile foundations to adjacent surcharge[J].Rock and Soil Mechanics,2014,35(S2):528-534.
[23] 张浩,石名磊,郭院成,等.不平衡堆载作用下邻近结构桩的侧向受力机制[J].岩土工程学报,2016,38(12):2226-2236. ZHANG Hao,SHI Ming-lei,GUO Yuan-cheng,et al.Lateral mechanical behaviors of structural piles adjacent to unbalanced surcharge loads[J].Chinese Journal of Geotechnical Engineering,2016,38(12):2226-2236.
[24] 张浩,石名磊,郭院成.土体侧移作用下被动桩受力变形的简化解析计算[J].东南大学学报:自然科学版,2016,46(2):392-399. ZHANG Hao,SHI Ming-lei,GUO Yuan-cheng.Simplified analytical calculation for forced deformation of passive pile subjected to lateral soil displacement[J].Journal of Southeast University:Natural Science Edition,2016,46(2):392-399.
[2] 冯忠居.特殊地区基础工程[M].北京:人民交通出版社,2008. FENG Zhong-ju.Foundation engineering in special areas[M].Beijing:China Communications Press,2008.
[3] DE BEER E E.The effects of horizontal loads on piles,due to surcharge or seismic effects[C]//ICSMFE.The Ninth Conference on Soil Mechanics and Foundation International Engineering.London:ICSMFE,1977:547-558.
[4] ELLIS E A,SPRINGMAN S M.Modelling of soil-structure interaction for a piled bridge abutment in plane strain FEM analyses[J].Computers and Geotechnics,2001,28(2):79-98.
[5] 陈福全,杨敏.地面堆载作用下邻近桩基性状的数值分析[J].岩土工程学报,2005,27(11):1286-1290. CHEN Fu-quan,YANG Min.Numerical analysis of piles influenced by lateral soil movement due to surcharge loads[J].Chinese Journal of Geotechnical Engineering,2005,27(11):1286-1290.
[6] 聂如松,冷伍明,杨奇,等.路基填土对桥台桩基影响的试验与数值仿真分析[J].岩土力学,2009,30(9):2862-2868. NIE Ru-song,LENG Wu-ming,YANG Qi,et al.Field test and 3D FEM studies of bridge abutment on piled foundation subjected to embankment load[J].Rock and Soil Mechanics,2009,30(9):2862-2868.
[7] MUTHUKKUMARAN K,KRISHNAN M G.Three dimensional analysis of piles on sloping ground subjected to passive load induced by surcharge[J].International Journal of Engineering and Technology Innovation,2012,2(1):31-47.
[8] KARIM M R.Behaviour of piles subjected to passive subsoil movement due to embankment construction-A simplified 3D analysis[J].Computers and Geotechnics,2013,53:1-8.
[9] 李志伟.软土地基邻近堆载对桥梁桩基偏位的影响研究[J].岩土力学,2013,34(12):3594-3600. LI Zhi-wei.Study of influence of surcharge load on lateral displacement of bridge piled foundation in soft ground[J].Rock and Soil Mechanics,2013,34(12):3594-3600.
[10] 李志伟.软土地基不对称堆载对桥梁偏位的影响及加固分析[J].公路,2016(8):86-92. LI Zhi-wei.Analysis of the influence of asymmetric load on deflection of bride and reinforcement in soft ground[J].Highway,2016(8):86-92.
[11] 董亮,牛斌,谷牧,等.大面积单侧堆载对高速铁路桥梁墩台影响的数值分析[J].铁道建筑,2015(1):39-42. DONG Liang,NIU Bin,GU Mu,et al.Numerical analysis on influence of large-area one-side surcharge load on abutments and piers of high speed railway bridges[J].Railway Engineering,2015(1):39-42.
[12] 邵曼.软土地区堆载对邻近高架桥墩的影响分析[J].公路工程,2016,41(3):212-215. SHAO Man.Numerical analysis on influence of pit excavation on adjacent bridge capped piles group[J].Highway Engineering,2016,41(3):212-215.
[13] 冯君,张俊云,朱明,等.软土地层高承台桥梁群桩基础横向承载特性研究[J].岩土力学,2016,37(增2):94-104. FENG Jun,ZHANG Jun-yun,ZHU Ming,et al.Characteristic study of horizontal bearing capacity and pile group effect coefficient of laterally loaded high pile group foundation for bridge in soft soil[J].Rock and Soil Mechanics,2016,37(S2):94-104.
[14] 聂如松,冷伍明,魏丽敏,等.堆载对既有桥墩桩基础影响距离分析[J].水文地质工程地质,2017,44(1):64-70. NIE Ru-song,LENG Wu-ming,WEI Li-min,et al.An analysis of the distance between surcharge load and existing bridged pile foundation in soft clay[J].Hydrogeology & Engineering Geology,2017,44(1):64-70.
[15] BRANSBY M F,SPRINGMAN S M.3-D finite element modelling of pile groups adjacent to surcharge loads[J].Computers and Geotechnics,1996,19(4):301-324.
[16] BRANSBY M F,SPRINGMAN S M.Centrifuge modelling of pile groups adjacent to surcharge loads[J].Soils and Foundations,1997,37(2):39-49.
[17] SPRINGMAN S M,BOLTON M D.The effect of surcharge loading adjacent to piles[R].Washington DC:Transport and Road Research Laboratory,1990.
[18] 陈雪华,律文田,王永和.台后填土对桥台桩基的影响分析[J].岩土工程学报,2006,28(7):910-913. CHEN Xue-hua,LU Wen-tian,WANG Yong-he.In-situ test of negative friction of abutment piles in soft soil[J].Chinese Journal of Geotechnical Engineering,2006,28(7):910-913.
[19] 丁任盛.临近堆载对深厚软土桩基影响的现场试验研究[J].铁道科学与工程学报,2015,12(2):291-296. DING Ren-sheng.Field test study on pile foundation subjected to adjacent surcharge in deep-soft soil strata[J].Journal of Railway Science and Engineering,2015,12(2):291-296.
[20] WANG L Z,CHEN K X,HONG Y,et al.Effect of consolidation on responses of a single pile subjected to lateral soil movement[J].Canadian Geotechnical Journal,2014,52(6):769-782.
[21] 李忠诚,梁志荣.大面积堆载土体侧移模式及对邻近被动桩影响分析[J].岩土工程学报,2010,32(增1):128-134. LI Zhong-cheng,LIANG Zhi-rong.Calculation model and numerical analysis of passive piles subjected to adjacent surcharge loads[J].Chinese Journal of Geotechnical Engineering,2010,32(S1):128-134.
[22] 冯昌明,木林隆,孙志伟,等.基于两阶段法的堆载对公路桥梁桩基础影响分析[J].岩土力学,2014,35(增2):528-534. FENG Chang-ming,MU Lin-long,SUN Zhi-wei,et al.Two-stage analysis of responses of bridge pile foundations to adjacent surcharge[J].Rock and Soil Mechanics,2014,35(S2):528-534.
[23] 张浩,石名磊,郭院成,等.不平衡堆载作用下邻近结构桩的侧向受力机制[J].岩土工程学报,2016,38(12):2226-2236. ZHANG Hao,SHI Ming-lei,GUO Yuan-cheng,et al.Lateral mechanical behaviors of structural piles adjacent to unbalanced surcharge loads[J].Chinese Journal of Geotechnical Engineering,2016,38(12):2226-2236.
[24] 张浩,石名磊,郭院成.土体侧移作用下被动桩受力变形的简化解析计算[J].东南大学学报:自然科学版,2016,46(2):392-399. ZHANG Hao,SHI Ming-lei,GUO Yuan-cheng.Simplified analytical calculation for forced deformation of passive pile subjected to lateral soil displacement[J].Journal of Southeast University:Natural Science Edition,2016,46(2):392-399.