路堤下桩—网复合地基作用机理及变形特性研究
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摘要
如何控制工后沉降和提高施工速度是在软基上修建高速铁(公)路时面临的两大技术难题。桩-网复合地基的推出为解决快速施工条件下的路基工后沉降控制问题提供了新的途径。目前该方法在工程上已经有一定应用并取得较好的效果,但由于桩-网复合地基的工作机理十分复杂,其理论研究远远落后于工程应用,在很大程度上制约了其推广应用。
本文首先梳理了桩-网复合地基的基本理论,对其加固机理以及土拱效应和薄膜张拉效应作了简要介绍。然后对路堤-桩-网复合地基体系作适当简化,通过Plaxis2D建立二维路堤模型对路堤下桩-网复合地基的各部分力学性状以及复合地基的作用机理进行了有限元分析,并详细分析了软土层模量、下卧层模量、土工格栅抗拉刚度、CFG桩体模量、桩长及桩间距布置等影响因素对复合地基承载特性和各部分力学性状的影响规律。最后利用有限元方法对路堤作用下桩-网复合地基的变形,包括侧向变形和沉降规律及其影响因素作了详细的研究,并针对工程应用中的一些问题给出了具体建议。本文在研究过程中分别考虑了路堤填筑阶段和固结阶段桩-网复合地基的不同力学性状及变形特点。
Residual settlement control and construction speed improvement are two technology difficulties if high speed railway and express road are built in soft soil.There emerged pile-net composite foundation, which a new way to solve stability and residual settlement control, and it is used in construetion with effective performance.But the working mechanism of pile-net composite foundation is very complex, the theoretical research is far behind the engineering practice, to some extent limited its popularization and application.
At first, this paper combs the basic theory of pile-net composite foundation, briefly introduces the reinforcement mechanism and the soil arching effect and membrane effect.And then appropriately simplify the embankment-pile-net composite foundation system, establish a two-dimensional model of the composite foundation by Plaxis2D, do finite element analysis about mechanical behaviors and mechanism of portions of pile-net composite foundation under embankment. A detailed analysis of the soft soil layer moduli, crouching modulus, geotechnical grid under tensile stiffness, modulus, length of CFG pile and pile spacing, layout and other influence factors on bearing capacity of composite Foundation and the law of some mechanical properties.Finally using finite element method detailed study of the embankment pile under-net composite foundation deformation, including lateral deformation and settlement rules and its influencing factors, made specific recommendations for some of the problems of engineering applications.Based on the study were considered in the process of the embankment filling and consolidation phase pile-net composite foundation of different mechanical properties and deformation characteristics.
本文首先梳理了桩-网复合地基的基本理论,对其加固机理以及土拱效应和薄膜张拉效应作了简要介绍。然后对路堤-桩-网复合地基体系作适当简化,通过Plaxis2D建立二维路堤模型对路堤下桩-网复合地基的各部分力学性状以及复合地基的作用机理进行了有限元分析,并详细分析了软土层模量、下卧层模量、土工格栅抗拉刚度、CFG桩体模量、桩长及桩间距布置等影响因素对复合地基承载特性和各部分力学性状的影响规律。最后利用有限元方法对路堤作用下桩-网复合地基的变形,包括侧向变形和沉降规律及其影响因素作了详细的研究,并针对工程应用中的一些问题给出了具体建议。本文在研究过程中分别考虑了路堤填筑阶段和固结阶段桩-网复合地基的不同力学性状及变形特点。
Residual settlement control and construction speed improvement are two technology difficulties if high speed railway and express road are built in soft soil.There emerged pile-net composite foundation, which a new way to solve stability and residual settlement control, and it is used in construetion with effective performance.But the working mechanism of pile-net composite foundation is very complex, the theoretical research is far behind the engineering practice, to some extent limited its popularization and application.
At first, this paper combs the basic theory of pile-net composite foundation, briefly introduces the reinforcement mechanism and the soil arching effect and membrane effect.And then appropriately simplify the embankment-pile-net composite foundation system, establish a two-dimensional model of the composite foundation by Plaxis2D, do finite element analysis about mechanical behaviors and mechanism of portions of pile-net composite foundation under embankment. A detailed analysis of the soft soil layer moduli, crouching modulus, geotechnical grid under tensile stiffness, modulus, length of CFG pile and pile spacing, layout and other influence factors on bearing capacity of composite Foundation and the law of some mechanical properties.Finally using finite element method detailed study of the embankment pile under-net composite foundation deformation, including lateral deformation and settlement rules and its influencing factors, made specific recommendations for some of the problems of engineering applications.Based on the study were considered in the process of the embankment filling and consolidation phase pile-net composite foundation of different mechanical properties and deformation characteristics.
引文
[1]饶为国.桩网复合地基原理及实践[M].北京：中国水利水电出版社,2004.
[2]Card, G.B.and Carter, G.R.(1995)."Case history of a piled embankment in London's Docklands." Engineering Geology of Construction Geological Soeiety Engineering Geology SPecial Publication, 10,79-84.
[3]张建勋,陈福全,简洪钰.桩承土工织物加筋地基的研究与工程应用综述[J].福建工程学院学报,2003,(3)：10～15.
[4]Alexie.D.Piled Embankment Design:Methods and Case Sutdies.proc.XV Italian Conference on Geosynhtetics, Bologna.October 2002.
[5]Reid, W.M, Buchanan, N W. Bridges approach support piling.piling and ground treatment [M].London:Thomas Telford Ltd,1984.267-274.
[6]Broms B B, Chandrasekaran G, Wang K S. Fabric reinforced retaining walls [A].International Symposiumon Application of Geosynthetic Technology [C].Jakarta:Indonsia Chaper-International Geosynthetics Society,1992.1-30.
[7]Jones C J, Lawson C R, Ayres D J.Geotextile reinforced piled embankment [A].Geotextiles Geomembrances and Relate Produces[C].Balkema,1990.155-159.
[8]Han J, Akins K. Use of geogrid-reinforce and pile-supported earth structures[A].Proceeding of International Deep Foundation Congress[C] Frlando, F1,2002.668-679.
[9]Gray D H Al-Refeai T.Behavior of fabric vs fiber-reinforced sand[J]. Journal of the Geotechnical Engineering, American society of Civil Engineers,1986,112(8):804-820.
[10]贾宁,陈仁朋等.杭甬高速公路拓宽工程理论分析及监测[J].岩土工程学报,2004(6).755～760.
[11]蒋关鲁,詹永祥等.无碴轨道桩板结构路基设计理论及计算理论的探讨[C].铁路客运专线建设技术交流会论文集,2005：398～401.
[12]JonesC.J.F.P, LawsonC.R, andAyresD.J.Geotextile.reinforced pile embankment[J].In Gentextile Gemembranes and Related Products.1990:155-159.
[13]Terzaghi, K.Theoretical soil mechanics [M]. New York:John Wiley&Son,1943.
[14]Low B K, Tang S K, Choa V.Arching in piled embankments.Journal of Geotechnical Engineering, ASCE,1993,120(11):1917-1938.
[15]阎明礼,吴春林,杨军.水泥粉煤灰碎石桩复合地塞试验研究[J].岩土工程学报,1996,18(2)：55---62.
[16]Hewlett, W J,Randolph, M F.Analysis of piled embankments[J]. Ground Engineering,1998. (3):12-18.
[17]牛志荣,李宏,穆建春等.复合地基处理及其工程实例[M].北京：中国建材工业出版社,2000.
[18]吴慧明,龚晓南.刚性基础与柔性基础下复合地基模型试验对比研究[J].土木工程学报,2001,34(5)：81～84.
[19]冯瑞玲.柔性基础下复合地基受力与变形性状的CAT仿真分析[D].长安大学2010.
[20]曾开华,俞建霖等.高速公路通道软基低强度混凝土桩处理试验研究[J].岩土工程学报,2003,25(6)：715～719.
[21]饶为国,赵成刚.桩-网复合地基应力比分析与计算[J].土木工程学报,2002,35(2)：74～80.
[22]朱云升,胡幼常等.柔性基础复合地基力学性状的有限元分析[J].岩土力学,2003,24(3)：395～400.
[23]刘吉福.路堤下复合地基桩、土应力比分析[J].岩石力学与工程学报,2003,22(4)：674～677.
[24]沈伟,池跃君等.考虑桩、土、垫层协同作用的刚性桩复合地基沉降计算方法[J].工程力学,2003,20(2)：36～42.
[25]贾宁.软土地基高速公路拓宽的沉降性状及处理研究[D].浙江大学.2004.
[26]费康,刘汉龙等.路堤下现浇薄壁管桩复合地基工作特性分析[J].岩土力学,2004,25(9)：1390～1396.
[27]晏莉,阳军生等.桩承土工合成材料加筋垫层复合地基作用原理及应用[J].岩土力学,2005,26(5)：821～826.
[28]曹新文,卿三惠等.桩网复合地基土工格栅加筋效应的试验研究[J].岩石力学与工程学报,2006,25(增1)：3162～3167.
[29]陈娟,吴西臣.桩网复合地基桩土应力比的确定[J].水文地质工程地质,2007,43(3)：116-119.
[30]连峰,龚晓南等.桩-网复合地基承载性状现场试验研究[J].岩土力学,2009,30(4)：1057～1062.
[31]肖启航.高速铁路CFG桩复合地基的沉降特性研究[D].西南交通大学.2010.
[32]张良,罗强等.基于现场试验的桩网复合地基垫层效应分析[J].西南交通大学学报,2010,45(5)：787～793.
[33]郑刚,刘力等.刚性桩加固软弱地基上路堤的稳定性问题(I)—存在问题及单桩条件下 的分析[J]_岩土工程学报,2010,32(11)：1648～1657.
[34]郑刚,刘力等.刚性桩加固软弱地基上路堤稳定性问题(Ⅱ)——群桩条件下的分析[J].岩土工程学报,2010,32(12)：1811～1820.
[35]赖伟.潮汕车站软土桩网复合地基负摩阻力特性研究[D].西南交通大学.2011.
[36]徐日庆,王景春.土工合成材料应用技术.[M].北京：化学工业出版社.2005.
[37]H.G.Kempfert,Berhane Gebreselassie Excavations and Foundations in Soft Soils[M]. Springer, 2006.
[38]张建勋,陈福全,简洪钰.被动桩中土拱效应问题的数值分析[J].岩土力学,2004,25(2)：174～178.
[39]Terzaghi K.Stress distribution in dry and in safurated sand above a yidlding trap door in 1st Int.Conf.on Soil Mechanics and Foundation Engineering,page306-311, Harvard Univ,Cambridge, Mass,1936.
[40]工程地质手册[M].北京：中国建筑工业出版社,2007.
[41]铁路工程地质手册[M].北京：中国铁道出版社.1999.
[42]中华人民共和国交通部部标准.公路工程名词术语(JTJ002-87).北京：人民交通出版社.1999.
[43]中华人民共和国行业标准.公路路基设计规范(JTG D30-2004).北京：人民交通出版社.2005.
[44]黄生文.公路工程地基处理手册[M].北京：人民交通出版社.2004.
[45]Whyte D. The overriding aspects of the design of geosynthetic-einforced pile supported embankments. In:proceedings of Contemporary Issues in FoundationEngineering, New York: ASCE publications,2005,29-41
[46]AMBILY A P, GANDH I S R. Behavior of Stone Columns Based on Exper imental and FEM Analysis[J] Journa 1 of Geotechnical and Geoenvir onmental Engineering,2007,133(4): 406-415.
[47]MalekM.Smadi,Ph.D,Lateral Deformation and Associated Settlement Resulting fromEmbankment Loading of soft Clay and silt deposits[D],2002,6-66.
[48]刘俊飞,赵健等.刚性桩桩网复合地基桩顶段桩间土附加应力分析[J].中国铁道科学,2004,25(2)：174～178.
[49]中华人民共和国建设部.JGJ79-2002建筑地基处理技术规范[s].北京：中国建筑工业出版社,2002.
[50]雷金波,姜弘道,郑云扬等.带帽桩复合地基复合桩土应力比的计算及影响因素分析[J].岩 土工程学报,2005,27(11)：1300～1305.
[51]史佩栋.实用桩基工程手册[M].北京：中国建筑下业出版社,1999.
[2]Card, G.B.and Carter, G.R.(1995)."Case history of a piled embankment in London's Docklands." Engineering Geology of Construction Geological Soeiety Engineering Geology SPecial Publication, 10,79-84.
[3]张建勋,陈福全,简洪钰.桩承土工织物加筋地基的研究与工程应用综述[J].福建工程学院学报,2003,(3)：10～15.
[4]Alexie.D.Piled Embankment Design:Methods and Case Sutdies.proc.XV Italian Conference on Geosynhtetics, Bologna.October 2002.
[5]Reid, W.M, Buchanan, N W. Bridges approach support piling.piling and ground treatment [M].London:Thomas Telford Ltd,1984.267-274.
[6]Broms B B, Chandrasekaran G, Wang K S. Fabric reinforced retaining walls [A].International Symposiumon Application of Geosynthetic Technology [C].Jakarta:Indonsia Chaper-International Geosynthetics Society,1992.1-30.
[7]Jones C J, Lawson C R, Ayres D J.Geotextile reinforced piled embankment [A].Geotextiles Geomembrances and Relate Produces[C].Balkema,1990.155-159.
[8]Han J, Akins K. Use of geogrid-reinforce and pile-supported earth structures[A].Proceeding of International Deep Foundation Congress[C] Frlando, F1,2002.668-679.
[9]Gray D H Al-Refeai T.Behavior of fabric vs fiber-reinforced sand[J]. Journal of the Geotechnical Engineering, American society of Civil Engineers,1986,112(8):804-820.
[10]贾宁,陈仁朋等.杭甬高速公路拓宽工程理论分析及监测[J].岩土工程学报,2004(6).755～760.
[11]蒋关鲁,詹永祥等.无碴轨道桩板结构路基设计理论及计算理论的探讨[C].铁路客运专线建设技术交流会论文集,2005：398～401.
[12]JonesC.J.F.P, LawsonC.R, andAyresD.J.Geotextile.reinforced pile embankment[J].In Gentextile Gemembranes and Related Products.1990:155-159.
[13]Terzaghi, K.Theoretical soil mechanics [M]. New York:John Wiley&Son,1943.
[14]Low B K, Tang S K, Choa V.Arching in piled embankments.Journal of Geotechnical Engineering, ASCE,1993,120(11):1917-1938.
[15]阎明礼,吴春林,杨军.水泥粉煤灰碎石桩复合地塞试验研究[J].岩土工程学报,1996,18(2)：55---62.
[16]Hewlett, W J,Randolph, M F.Analysis of piled embankments[J]. Ground Engineering,1998. (3):12-18.
[17]牛志荣,李宏,穆建春等.复合地基处理及其工程实例[M].北京：中国建材工业出版社,2000.
[18]吴慧明,龚晓南.刚性基础与柔性基础下复合地基模型试验对比研究[J].土木工程学报,2001,34(5)：81～84.
[19]冯瑞玲.柔性基础下复合地基受力与变形性状的CAT仿真分析[D].长安大学2010.
[20]曾开华,俞建霖等.高速公路通道软基低强度混凝土桩处理试验研究[J].岩土工程学报,2003,25(6)：715～719.
[21]饶为国,赵成刚.桩-网复合地基应力比分析与计算[J].土木工程学报,2002,35(2)：74～80.
[22]朱云升,胡幼常等.柔性基础复合地基力学性状的有限元分析[J].岩土力学,2003,24(3)：395～400.
[23]刘吉福.路堤下复合地基桩、土应力比分析[J].岩石力学与工程学报,2003,22(4)：674～677.
[24]沈伟,池跃君等.考虑桩、土、垫层协同作用的刚性桩复合地基沉降计算方法[J].工程力学,2003,20(2)：36～42.
[25]贾宁.软土地基高速公路拓宽的沉降性状及处理研究[D].浙江大学.2004.
[26]费康,刘汉龙等.路堤下现浇薄壁管桩复合地基工作特性分析[J].岩土力学,2004,25(9)：1390～1396.
[27]晏莉,阳军生等.桩承土工合成材料加筋垫层复合地基作用原理及应用[J].岩土力学,2005,26(5)：821～826.
[28]曹新文,卿三惠等.桩网复合地基土工格栅加筋效应的试验研究[J].岩石力学与工程学报,2006,25(增1)：3162～3167.
[29]陈娟,吴西臣.桩网复合地基桩土应力比的确定[J].水文地质工程地质,2007,43(3)：116-119.
[30]连峰,龚晓南等.桩-网复合地基承载性状现场试验研究[J].岩土力学,2009,30(4)：1057～1062.
[31]肖启航.高速铁路CFG桩复合地基的沉降特性研究[D].西南交通大学.2010.
[32]张良,罗强等.基于现场试验的桩网复合地基垫层效应分析[J].西南交通大学学报,2010,45(5)：787～793.
[33]郑刚,刘力等.刚性桩加固软弱地基上路堤的稳定性问题(I)—存在问题及单桩条件下 的分析[J]_岩土工程学报,2010,32(11)：1648～1657.
[34]郑刚,刘力等.刚性桩加固软弱地基上路堤稳定性问题(Ⅱ)——群桩条件下的分析[J].岩土工程学报,2010,32(12)：1811～1820.
[35]赖伟.潮汕车站软土桩网复合地基负摩阻力特性研究[D].西南交通大学.2011.
[36]徐日庆,王景春.土工合成材料应用技术.[M].北京：化学工业出版社.2005.
[37]H.G.Kempfert,Berhane Gebreselassie Excavations and Foundations in Soft Soils[M]. Springer, 2006.
[38]张建勋,陈福全,简洪钰.被动桩中土拱效应问题的数值分析[J].岩土力学,2004,25(2)：174～178.
[39]Terzaghi K.Stress distribution in dry and in safurated sand above a yidlding trap door in 1st Int.Conf.on Soil Mechanics and Foundation Engineering,page306-311, Harvard Univ,Cambridge, Mass,1936.
[40]工程地质手册[M].北京：中国建筑工业出版社,2007.
[41]铁路工程地质手册[M].北京：中国铁道出版社.1999.
[42]中华人民共和国交通部部标准.公路工程名词术语(JTJ002-87).北京：人民交通出版社.1999.
[43]中华人民共和国行业标准.公路路基设计规范(JTG D30-2004).北京：人民交通出版社.2005.
[44]黄生文.公路工程地基处理手册[M].北京：人民交通出版社.2004.
[45]Whyte D. The overriding aspects of the design of geosynthetic-einforced pile supported embankments. In:proceedings of Contemporary Issues in FoundationEngineering, New York: ASCE publications,2005,29-41
[46]AMBILY A P, GANDH I S R. Behavior of Stone Columns Based on Exper imental and FEM Analysis[J] Journa 1 of Geotechnical and Geoenvir onmental Engineering,2007,133(4): 406-415.
[47]MalekM.Smadi,Ph.D,Lateral Deformation and Associated Settlement Resulting fromEmbankment Loading of soft Clay and silt deposits[D],2002,6-66.
[48]刘俊飞,赵健等.刚性桩桩网复合地基桩顶段桩间土附加应力分析[J].中国铁道科学,2004,25(2)：174～178.
[49]中华人民共和国建设部.JGJ79-2002建筑地基处理技术规范[s].北京：中国建筑工业出版社,2002.
[50]雷金波,姜弘道,郑云扬等.带帽桩复合地基复合桩土应力比的计算及影响因素分析[J].岩 土工程学报,2005,27(11)：1300～1305.
[51]史佩栋.实用桩基工程手册[M].北京：中国建筑下业出版社,1999.