深海平台桩基的承载力研究
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摘要
固定式采油平台工作水深随着深度增加,造价越来越昂贵,重力式平台和导管架平台已经不能适应深水油气田的开发。因此,浮式平台和顺应式平台被越来越多的应用于实际工程当中。作为深海平台的主要锚固基础之一,桩基适用范围很广、可以有效抵抗循环荷载,而且建造成本低、易于运输、是唯一既适用于悬链线式锚泊系统又适用于张拉或半张拉式锚泊系统的锚固基础。
由于桩土相互作用的复杂性,要想获得解析解是非常困难的,所以利用有限元法对该问题进行数值分析是非常必要的。本文利用Plaxis 3D Foundation建立了桩土相互作用的有三维限元计算模型来模拟桩和土的几何、力学特性。利用有限元法作为基本工具,对斜向拔力作用下的桩基承载力,桩土相互作用机理进行了探讨。
本文首先总结了目前国内外对于桩基抗拉拔承载力研究的现状。随后,简要的介绍了论文中所用的有限元分析软件Plaxis 3D Foundation,详细说明计算分析原理及土的本构模型。最后,以Su=1Z和Su=2Z为代表,采用了Mohr-Coulomb弹塑性本构模型,对长度为30m、60m和80m的桩基进行三维有限元分析,得到了桩基在斜向拔力作用下的极限承载力,并对不同系泊点、加载角度和不同长度的桩基的抗拉拔承载力的影响做了研究。此外,本文还利用Plaxis软件对陈永福模型试验分别建立了静力有限元和动力有限元桩土模型,研究了模型桩桩土相互作用区域,应变累积。
现在,随着深海平台不断的安装架设,对于深海平台桩基的研究将有助于我国对南海深海石油开发,并为我国深水深海平台的设计和研发提供可靠的依据。
With the water depth increment in ocean engineering, costs of fixed platforms grow rapidly, and gravity platforms or jacket platforms have been unable to meet deepwater oil field development. Therefore, it is necessary to develop the technology of floating platforms and compliant platforms. As one of the main anchor foundation of the platform in deepsea area, pile foundation was widely used in deepsea platforms because of its low cost, convenience of transportation, effectiveness of resisting cyclic loads,and the only anchor foundation suitable for the Catenary Mooring System and tension and semi-tension Mooring System.
The problem of the pile-soil interaction is so complex that it is impossible to gain any analytical result. Thus, it is important to employ the finite element method to analyze this problem.In this paper a three-dimensional numerical model is established by Plaxis 3D Foundation to simulate the geometrical and mechanical characteristic of pile and the soil. Based on the finite element method, ultimate bearing capacity and the interaction merchanism between soil and pile under incline pullout load was studied
In this thesis, we summarize the theories about how to calculate the capacity of pile foundations. Then a brief introduction is made about the finite element analysis software--Plaxis 3D Foundation that is used to analyze the ultimate capacity of the foundations, detailed description the calculation of principle and constitutive model. Finally, two soil profiles Su=1Z and Su=2Z are chosen to do analysis.
Three-dimensional FEM with Mohr-Coulomb elasto-plastic constitutive model calculation are done for pile with 30m, 60m&80m length. The purpose of our study is to find the ultimate bearing capacity of the pile foundation under incline pullout load, and the influence of mooring attachment, shear strength and load angle . Additional, based on the Plaxis software and ChenYongfu model-pile test, this paper generates pile-soil interaction finite element model under static loading and cyclic loading to analyze the piles-soil interaction areas and strain accumulation.
At present, the platforms are being constructed in deepsea or even in ultra-deepsea. To study more about pile foundation of platform in deepsea area will help us to exploit China South Sea efficiently and provide the reliable gist for developing our own technology of platforms in deepsea area.
由于桩土相互作用的复杂性,要想获得解析解是非常困难的,所以利用有限元法对该问题进行数值分析是非常必要的。本文利用Plaxis 3D Foundation建立了桩土相互作用的有三维限元计算模型来模拟桩和土的几何、力学特性。利用有限元法作为基本工具,对斜向拔力作用下的桩基承载力,桩土相互作用机理进行了探讨。
本文首先总结了目前国内外对于桩基抗拉拔承载力研究的现状。随后,简要的介绍了论文中所用的有限元分析软件Plaxis 3D Foundation,详细说明计算分析原理及土的本构模型。最后,以Su=1Z和Su=2Z为代表,采用了Mohr-Coulomb弹塑性本构模型,对长度为30m、60m和80m的桩基进行三维有限元分析,得到了桩基在斜向拔力作用下的极限承载力,并对不同系泊点、加载角度和不同长度的桩基的抗拉拔承载力的影响做了研究。此外,本文还利用Plaxis软件对陈永福模型试验分别建立了静力有限元和动力有限元桩土模型,研究了模型桩桩土相互作用区域,应变累积。
现在,随着深海平台不断的安装架设,对于深海平台桩基的研究将有助于我国对南海深海石油开发,并为我国深水深海平台的设计和研发提供可靠的依据。
With the water depth increment in ocean engineering, costs of fixed platforms grow rapidly, and gravity platforms or jacket platforms have been unable to meet deepwater oil field development. Therefore, it is necessary to develop the technology of floating platforms and compliant platforms. As one of the main anchor foundation of the platform in deepsea area, pile foundation was widely used in deepsea platforms because of its low cost, convenience of transportation, effectiveness of resisting cyclic loads,and the only anchor foundation suitable for the Catenary Mooring System and tension and semi-tension Mooring System.
The problem of the pile-soil interaction is so complex that it is impossible to gain any analytical result. Thus, it is important to employ the finite element method to analyze this problem.In this paper a three-dimensional numerical model is established by Plaxis 3D Foundation to simulate the geometrical and mechanical characteristic of pile and the soil. Based on the finite element method, ultimate bearing capacity and the interaction merchanism between soil and pile under incline pullout load was studied
In this thesis, we summarize the theories about how to calculate the capacity of pile foundations. Then a brief introduction is made about the finite element analysis software--Plaxis 3D Foundation that is used to analyze the ultimate capacity of the foundations, detailed description the calculation of principle and constitutive model. Finally, two soil profiles Su=1Z and Su=2Z are chosen to do analysis.
Three-dimensional FEM with Mohr-Coulomb elasto-plastic constitutive model calculation are done for pile with 30m, 60m&80m length. The purpose of our study is to find the ultimate bearing capacity of the pile foundation under incline pullout load, and the influence of mooring attachment, shear strength and load angle . Additional, based on the Plaxis software and ChenYongfu model-pile test, this paper generates pile-soil interaction finite element model under static loading and cyclic loading to analyze the piles-soil interaction areas and strain accumulation.
At present, the platforms are being constructed in deepsea or even in ultra-deepsea. To study more about pile foundation of platform in deepsea area will help us to exploit China South Sea efficiently and provide the reliable gist for developing our own technology of platforms in deepsea area.
引文
[1]李润培,谢永和,舒志深海平台技术的研究现状与发展趋势,中国海洋平台,2003,18(3):1~5
[2]金庆焕,深水油气是当今海洋油气勘探的主要热点,科学中国人,2006,11
[3] G.G.Meyerhof and J.I.Adams.The ultimate uplift capacity of foundations.Canadian Geotechnical Journal.1968,5(4),225~244
[4] De Nicola,A.and Randolph,M.F..Tensive and Compressive Shaft Capacity of Piles in Sand.Journal of Geotechnical Engineering.1993,119(12):1952~1973
[5]刘祖德,抗拔桩基础,《桩基工程技术》,刘金励主编,北京,中国建材工业出版社,1996:642~674
[6]黄锋,单桩在压与拔荷载下桩侧摩阻力发展机理研究,[博士学位论文],北京:清华大学,1998
[7] N.F.Ismael and H.A.Al~Sanad.Uplift capacity of bored piles in calcareous soils.Journal of Geotechnical Engineering.1985,116(10): 928~940
[8] N.F.Ismael,H.A.Al~Sanad and F.Al~Otaihi.Tension tests on bored piles in cemented desert sands.Canadian Geotechnical Journal.1994,31 597~603
[9] E.S.B.Reddy,M.O'Reilly and D.N.Chapman.Modified t~z model-a software for tension piles. Computers and Structures.1998,68:613~625
[10] Ahmed Shlash Alawneh,Abdallah I.Husein Malkawi,and Husein AI~Deeky.Tension tests on smooth and rough model piles in dry sand.Canadian Geotechnical Journal.1999,36, 746~753
[11] Van Baars S &Van Niekerk,W.J.,Numerical modelling of tension piles,Int.Symposium Beyond 2000 in Computational Geotechnics,Balkema,Lisse NL,1999
[12]刘文白,承受上拔荷载的基础,《桩基工程的理论进展与工程实践》,刘利民等编,北京:中国建材工业出版社,2002
[13]许宏发,桩的抗拔承载力与非线性计算理论研究:博士学位论文,南京:解放军理工大学工程兵工程学院.2001
[14]陈波,吕西林,李培振等,均匀土~桩基~结构相互作用体系的计算分析,地震工程与工程振动,2002,22(3):91~99
[15]皇甫明,王幼青,张军,纵横向荷载作用下桩的工作性状研究,哈尔滨工业大学学报, 2003年,35:743~745
[16] B.K.Dash and P.J.Pise.Effect of Compressive Load on Uplift Capacity of Model Piles.Journal of Geotechnical and Geoenvironmental Engineering.2003,129(11):987~992
[17]丁佩民,黄堂松,肖志斌,抗拔桩侧摩阻力发挥规律的探讨,建筑科学,19(6),2003
[18] D.M.Potts.43th Rankine lecture:Numerical analysis:a virtual dream or practice reality. Geotechnique.2003,56(6)
[19]杨什生.软土地基中抗拔桩的受力与变形性状研究,(硕士学位论文),浙江大学.2003
[20]刘文白,周健.上拔荷载作用下扩展基础的颗粒流数值模拟,水利学报,第12期
[21]张洁,尚岳全,林旭武.考虑上拔力作用点位置影响的抗拔桩变形分析.土木工程学报,2005(7)
[22]张晓强,纵横向同时受荷桩工作性状试验研究,硕士学位论文,河海大学,2007
[23]徐和,陈竹昌,任陈宝,向循环荷载作用下砂土中模型桩的试验研究,岩土工程学报,1989,11(4):64~71
[24]陈竹昌,徐和,土类对轴向循环荷载下桩性状的影响,同济大学学报,1989,17(3) 329~336
[25]徐和,陈竹昌,不同砂土密度对竖直桩轴向抗拔承载力的影响,特种结构,1996,13(2): 53~57
[26]陈永福,砂土中桩在低频轴向动力荷载作用下的特性,长沙交通学院学报,1992,8(4):74~78
[27]林天健,熊厚金,王力群,桩基础设计指南[M],北京:中国建筑工业出版社,1999
[28] Randolph M.F and WorthCP. Analysis of Deformation of Vertically Loaded Piles [J].Journal of the Geotechnical Engineering Division,ASCE,1978,14(12);1465~1488
[29]张尚根,陈志龙.等截面抗拔桩的变形分析.解放军理工大学学报,2002,3(5):71~73.
[30] Randolph M.F,Wroth C P,Analysis of Deformation of Vetically Loaded Pile,[J]. Jounral of Geotechnical Engineering,ASCE,1978,104(12):1465~1488
[31] Randolph.M.F,Science and Empiricism in pile foundation design [J],Geotechnique,2003,53(1):847~875
[32] Matlock H. Correlations for design of laterally~loaded piles in soft clay[C]. Proceeding of 2nd Offshore Technology Conference, Houston, 1970, Paper No.1204
[33] Reese L C, Cox W R. Analysis of Laterally~loaded Piles in Sand[C]. Proceeding of the 6th Offshore Technology Conference, Houston, 1974, Paper No.2080.
[34] American Petroleum Institute, Recommended Practice for Planning, Designingand Constructing Fixed Offshore Platforms~Working Stress Design~API RP 2A(WSD,Twenty~First Edition) December 2000
[35] Reese L C, Cox W R. Analysis of Laterally~loaded Piles in Sand[C]. Proceeding of the 6th Offshore Technology Conference, Houston, 1974, Paper No.2080
[36] O’Neill M W, Murchinson J M. An evaluation of p~y relationships in sand.Rep. Prepared for American Petroleum Institute, Washington, DC. 1983.
[37]韩理安,水平承载桩的计算,长沙:中南大学出版社,2004, 30~41
[38] GGMeyerhof&VVR.N.Sastry. Bearing capacity of rigid piles under eccentric and inclined loads [J] .Canadian geotechnical jounral,1985(22):267~276.
[39] K.Terzaghi.The oretical soil mechanics[M].NewYork:JohnWiley&SonsNY,1943.
[40] V.V.R.N.Sastry, CiG.Meyerhof,&T. Koumolo. Behavior of rigid piles in layered soils under eccentric and inclined loads Canadian geotechnical Jounral,1986(23):451~457.
[41] G.GMeyerhof,Bearing capacity and setlement of pile foundation[J].11thTerzaghi lecture,ASCE Journal of the geotechnical engineering division 1976,102(3):195~228.
[42] P K.Banerjee,&T.D.Davis.The behaviour of axially and laterally loaded singlepiles embedded in nounomogeneous soils[J].Geotechnique,1978,28:309~326.
[43] H.GPoulos&E.H.Davis. Elastic solutions for soil and rock mechanics[M]. New York: John wi ley & Sons,1974.
[44] V.V.I.Z.N.Sastry&G.GMeyerhof.Behavior of flexible piles under inclined loads[J].Canathan Geotechnical Jounral,1990(27):19~28
[45] V.V.R.N.Sastry&G.G.Meyerhof.Behavior of flexible piles in layered clays und er eccentirc and inclined loads[J].Canadian geotechnical journal,1995(32):387~396.
[46]钱家欢,殷宗泽主编,土工数值分析,北京:中国铁道出版社,1991
[47]钱家欢,殷宗泽主编,土工原理与计算,北京:中国水利水电出版社,1980,611~647
[48]张学言,闫澍旺,岩土塑性力学基础,北京:人民交通出版社,2003,88~92,70~72,97~103
[49]陈惠发,A,F,萨里普,弹性与塑性力学,余天庆,王勋文,刘在华编译,北京:中国建筑工业出版社,2004,198~255
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[52] Chairat Supachawarote, Mark Randolph, Susan Gourvenec. Inclined Pull~out Capacity of Suction Caissons.The Fourteenth(2004) International Offshore andPolar Engineering Conference Toulon,France,May 23~28,2004
[53]杜杰,丁红岩等,筒型基础有限元分析的土体边界选取研究,海洋技术,2005,6,109~113
[54]皇甫明,复杂荷载作用下桩的工作性能研究,工学硕士学位论文,哈尔滨工业大学,2002
[55] Shahrour Meimon. Analysis of the behavior of offshore piles under loads[A]. Proc Int Conf on Deep Foundations.1991;277~284.
[56]谢定义,土动力学,西安,西安交通大学出版社,1988,199~200
[57]陈仲颐,周景星,王洪瑾,土力学,北京:清华大学出版,2008,307~325
[2]金庆焕,深水油气是当今海洋油气勘探的主要热点,科学中国人,2006,11
[3] G.G.Meyerhof and J.I.Adams.The ultimate uplift capacity of foundations.Canadian Geotechnical Journal.1968,5(4),225~244
[4] De Nicola,A.and Randolph,M.F..Tensive and Compressive Shaft Capacity of Piles in Sand.Journal of Geotechnical Engineering.1993,119(12):1952~1973
[5]刘祖德,抗拔桩基础,《桩基工程技术》,刘金励主编,北京,中国建材工业出版社,1996:642~674
[6]黄锋,单桩在压与拔荷载下桩侧摩阻力发展机理研究,[博士学位论文],北京:清华大学,1998
[7] N.F.Ismael and H.A.Al~Sanad.Uplift capacity of bored piles in calcareous soils.Journal of Geotechnical Engineering.1985,116(10): 928~940
[8] N.F.Ismael,H.A.Al~Sanad and F.Al~Otaihi.Tension tests on bored piles in cemented desert sands.Canadian Geotechnical Journal.1994,31 597~603
[9] E.S.B.Reddy,M.O'Reilly and D.N.Chapman.Modified t~z model-a software for tension piles. Computers and Structures.1998,68:613~625
[10] Ahmed Shlash Alawneh,Abdallah I.Husein Malkawi,and Husein AI~Deeky.Tension tests on smooth and rough model piles in dry sand.Canadian Geotechnical Journal.1999,36, 746~753
[11] Van Baars S &Van Niekerk,W.J.,Numerical modelling of tension piles,Int.Symposium Beyond 2000 in Computational Geotechnics,Balkema,Lisse NL,1999
[12]刘文白,承受上拔荷载的基础,《桩基工程的理论进展与工程实践》,刘利民等编,北京:中国建材工业出版社,2002
[13]许宏发,桩的抗拔承载力与非线性计算理论研究:博士学位论文,南京:解放军理工大学工程兵工程学院.2001
[14]陈波,吕西林,李培振等,均匀土~桩基~结构相互作用体系的计算分析,地震工程与工程振动,2002,22(3):91~99
[15]皇甫明,王幼青,张军,纵横向荷载作用下桩的工作性状研究,哈尔滨工业大学学报, 2003年,35:743~745
[16] B.K.Dash and P.J.Pise.Effect of Compressive Load on Uplift Capacity of Model Piles.Journal of Geotechnical and Geoenvironmental Engineering.2003,129(11):987~992
[17]丁佩民,黄堂松,肖志斌,抗拔桩侧摩阻力发挥规律的探讨,建筑科学,19(6),2003
[18] D.M.Potts.43th Rankine lecture:Numerical analysis:a virtual dream or practice reality. Geotechnique.2003,56(6)
[19]杨什生.软土地基中抗拔桩的受力与变形性状研究,(硕士学位论文),浙江大学.2003
[20]刘文白,周健.上拔荷载作用下扩展基础的颗粒流数值模拟,水利学报,第12期
[21]张洁,尚岳全,林旭武.考虑上拔力作用点位置影响的抗拔桩变形分析.土木工程学报,2005(7)
[22]张晓强,纵横向同时受荷桩工作性状试验研究,硕士学位论文,河海大学,2007
[23]徐和,陈竹昌,任陈宝,向循环荷载作用下砂土中模型桩的试验研究,岩土工程学报,1989,11(4):64~71
[24]陈竹昌,徐和,土类对轴向循环荷载下桩性状的影响,同济大学学报,1989,17(3) 329~336
[25]徐和,陈竹昌,不同砂土密度对竖直桩轴向抗拔承载力的影响,特种结构,1996,13(2): 53~57
[26]陈永福,砂土中桩在低频轴向动力荷载作用下的特性,长沙交通学院学报,1992,8(4):74~78
[27]林天健,熊厚金,王力群,桩基础设计指南[M],北京:中国建筑工业出版社,1999
[28] Randolph M.F and WorthCP. Analysis of Deformation of Vertically Loaded Piles [J].Journal of the Geotechnical Engineering Division,ASCE,1978,14(12);1465~1488
[29]张尚根,陈志龙.等截面抗拔桩的变形分析.解放军理工大学学报,2002,3(5):71~73.
[30] Randolph M.F,Wroth C P,Analysis of Deformation of Vetically Loaded Pile,[J]. Jounral of Geotechnical Engineering,ASCE,1978,104(12):1465~1488
[31] Randolph.M.F,Science and Empiricism in pile foundation design [J],Geotechnique,2003,53(1):847~875
[32] Matlock H. Correlations for design of laterally~loaded piles in soft clay[C]. Proceeding of 2nd Offshore Technology Conference, Houston, 1970, Paper No.1204
[33] Reese L C, Cox W R. Analysis of Laterally~loaded Piles in Sand[C]. Proceeding of the 6th Offshore Technology Conference, Houston, 1974, Paper No.2080.
[34] American Petroleum Institute, Recommended Practice for Planning, Designingand Constructing Fixed Offshore Platforms~Working Stress Design~API RP 2A(WSD,Twenty~First Edition) December 2000
[35] Reese L C, Cox W R. Analysis of Laterally~loaded Piles in Sand[C]. Proceeding of the 6th Offshore Technology Conference, Houston, 1974, Paper No.2080
[36] O’Neill M W, Murchinson J M. An evaluation of p~y relationships in sand.Rep. Prepared for American Petroleum Institute, Washington, DC. 1983.
[37]韩理安,水平承载桩的计算,长沙:中南大学出版社,2004, 30~41
[38] GGMeyerhof&VVR.N.Sastry. Bearing capacity of rigid piles under eccentric and inclined loads [J] .Canadian geotechnical jounral,1985(22):267~276.
[39] K.Terzaghi.The oretical soil mechanics[M].NewYork:JohnWiley&SonsNY,1943.
[40] V.V.R.N.Sastry, CiG.Meyerhof,&T. Koumolo. Behavior of rigid piles in layered soils under eccentric and inclined loads Canadian geotechnical Jounral,1986(23):451~457.
[41] G.GMeyerhof,Bearing capacity and setlement of pile foundation[J].11thTerzaghi lecture,ASCE Journal of the geotechnical engineering division 1976,102(3):195~228.
[42] P K.Banerjee,&T.D.Davis.The behaviour of axially and laterally loaded singlepiles embedded in nounomogeneous soils[J].Geotechnique,1978,28:309~326.
[43] H.GPoulos&E.H.Davis. Elastic solutions for soil and rock mechanics[M]. New York: John wi ley & Sons,1974.
[44] V.V.I.Z.N.Sastry&G.GMeyerhof.Behavior of flexible piles under inclined loads[J].Canathan Geotechnical Jounral,1990(27):19~28
[45] V.V.R.N.Sastry&G.G.Meyerhof.Behavior of flexible piles in layered clays und er eccentirc and inclined loads[J].Canadian geotechnical journal,1995(32):387~396.
[46]钱家欢,殷宗泽主编,土工数值分析,北京:中国铁道出版社,1991
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