基于荷载传递曲线的大直径钢管桩水平受力特性分析方法
|
摘要
海上风电通常选用大直径钢管单桩基础。水平受力的大直径钢管桩桩截面转动引起的桩周土对桩的附加抗力作用较为显著,为考虑这部分附加抗力对大直径桩水平受力特性的影响,首先,提出适用于大直径钢管桩水平受力分析的修正文克勒地基梁模型,分别使用非线性弹簧模拟土和考虑剪切变形的C1型梁单元代表桩,假定桩单元内部土荷载传递曲线的割线刚度为线性分布,推导相应的有限元公式,形成考虑桩截面转动附加抗力作用的耦合法,并根据该算法编制程序。然后,基于现有的土荷载传递曲线使用耦合法对算例进行分析,以验证耦合法的合理性,并将其计算结果与仅考虑横向非线性弹簧作用的p-y法的计算结果进行对比分析。分析结果表明:耦合法可更好地预测大直径钢管桩的水平受力特性;大直径钢管桩桩身变形越接近于刚性转动,桩截面转动产生的附加土抗力作用越显著,当大直径钢管桩桩身变形接近于柔性变形时,桩截面转动产生的附加土抗力作用基本可以忽略。
Offshore turbines are often supported on large-diameter steel pipe monopoles. There is a significant effect of soil-added-resistance force caused by the rotation of the pile section of laterally loaded large-diameter steel pipe piles. The impact of the soil-added-resistance force on pile lateral capacity should be taken into account. A modified Winkler foundation beam model was proposed to model the lateral bearing loads of large-diameter steel pipe piles,in which the soil and the pile are respectively modeled by nonlinear springs and C1 beam elements considering the shear deformation. Assuming that the secant stiffness of the soil load transfer curves inside a pile element is linear,finite element formulas were deduced to develop a coupling method which can take into account the soil-added-resistance force caused by the rotation of the pile section,and a corresponding program was written. Two case studies were performed to verify the coupling method developed in this paper,and their computed results were compared with those obtained by the p-y method only considering the lateral nonlinear springs′ effect. The results show that the coupling method can better predict the laterally loaded characteristics of the large-diameter steel pipe pile. The closer the deformation of the large-diameter steel monopile is to the rigid rotation,the more obvious the soil-added-resistance force caused by the rotation of the pile section. On the contrary,the soil-added-resistance force can be ignored while the deformation of the large-diameter steel pipe pile is close to the flexible deformation.
Offshore turbines are often supported on large-diameter steel pipe monopoles. There is a significant effect of soil-added-resistance force caused by the rotation of the pile section of laterally loaded large-diameter steel pipe piles. The impact of the soil-added-resistance force on pile lateral capacity should be taken into account. A modified Winkler foundation beam model was proposed to model the lateral bearing loads of large-diameter steel pipe piles,in which the soil and the pile are respectively modeled by nonlinear springs and C1 beam elements considering the shear deformation. Assuming that the secant stiffness of the soil load transfer curves inside a pile element is linear,finite element formulas were deduced to develop a coupling method which can take into account the soil-added-resistance force caused by the rotation of the pile section,and a corresponding program was written. Two case studies were performed to verify the coupling method developed in this paper,and their computed results were compared with those obtained by the p-y method only considering the lateral nonlinear springs′ effect. The results show that the coupling method can better predict the laterally loaded characteristics of the large-diameter steel pipe pile. The closer the deformation of the large-diameter steel monopile is to the rigid rotation,the more obvious the soil-added-resistance force caused by the rotation of the pile section. On the contrary,the soil-added-resistance force can be ignored while the deformation of the large-diameter steel pipe pile is close to the flexible deformation.
引文
[1]ZHANG J,FOWAI I,SUN K.A glance at offshore wind turbine foundation structures[J].Brodogradnja,2016,67(2):101-113.
[2]塞尔瓦杜雷A P S.土与基础相互作用的弹性分析[M].范文田,何广汉,张式深,等译.北京:中国铁道出版社,1981:8.(SELVADURAL A P S.Elastic analysis of soil-foundation interaction[M].Translated by the FAN Wentian,HE Guanghan,ZHANG Shishen,et al.Beijing:China Railway Press,1981:8.(in Chinese))
[3]MCCLELLAND B,FOCHT J A.Soil modulus for laterally loaded piles[J].Transactions of the American Society of Civil Engineers,1958,123(1):1 049-1 063.
[4]REESE L C,COX W R,KOOP F D.Analysis of laterally loaded piles in sand[C]//Proceedings of 6th Annual Offshore Technology Conference.Dallas:[s.n.],1974:473-483.
[5]O′NEIL M W,MURCHISON J M.An evaluation of p-y relationships in sand[R].[S.l.]:Report of the American Petroleum Institute,1983.
[6]MURCHISON J M,O'NEILL M W.Evaluation of py relationships in cohesionless soils[C]//Analysis and Design of Pile Foundations.[S.l.]:[s.n.],1984:174-191.
[7]GEORGIADIS M,ANAGNOSTOPOULOS C,SAFLEKOU S.Centrifugal testing of laterally loaded piles in sand[J].Canadian Geotechnical Journal,1992,29(2):208-216.
[8]王国粹,杨敏.砂土中水平受荷桩非线性分析[J].岩土力学,2011,32(增2):261-267.(WANG Guocui,YANG Min.Nonlinear analysis of laterally loaded piles in sand[J].Rock and Soil Mechanics,2011,32(Supp.2):261-267.(in Chinese))
[9]MATLOCK H.Correlation for design of laterally loaded piles in soft clay[C]//Offshore Technology in Civil Engineering.[S.l.]:[s.n.],1970:77-94.
[10]REESE L C,WELCH R C.Lateral loading of deep foundations in stiff clay[J].Journal of Geotechnical and Geoenvironmental Engineering,1975,101(7):633-649.
[11]American Petroleum Institute.ISO 19901 Geotechnical and foundation design considerations[S].Washington,D.C.:American Petroleum Institute Publishing Services,2014.
[12]DNV GL Group.DNVGL-ST-0126,Support structures for wind turbines[S].Oslo:Det Norske Veritas,2016.
[13]中华人民共和国行业标准编写组.JTS 167-4-2012港口工程桩基规范[S].北京:人民交通出版社,2012.(The Professional Standards Compilation Group of People′s Republic of China.JTS167-4-2012Code for pile foundation of harbor engineering[S].Beijing:China Communications Press,2012.(in Chinese))
[14]FINN W L,DOWLING J.Modelling effects of pile diameter[J].Canadian Geotechnical Journal,2015,53(1):173-178.
[15]ALIKHANLOU F.A discrete model for the analysis of short pier foundations in clays[M.S.Thesis][D].[S.l.]:Annals of the Rheumatic Diseases,1981.
[16]ASHOUR M,HELAL A.Contribution of vertical skin friction to the lateral resistance of large-diameter shafts[J].Journal of Bridge Engineering,2014,19(2):289-302.
[17]BYRNE B W,MCADAM R,BURD H J,et al.New design methods for large diameter piles under lateral loading for offshore wind applications[C]//International Symposium on Frontiers in Offshore Geotechnics.Oslo:CRC Press,2015:705-710.
[18]LI W,ZHU B,YANG M.Static response of monopile to lateral load in overconsolidated dense sand[J].Journal of Geotechnical and Geoenvironmental Engineering,2017,143(7):04017026.
[19]王勖成.有限单元法[M].北京:清华大学出版社,2003:311-315.(WANG Xucheng.Finite element method[M].Beijing:Tsinghua University Press,2003:311-315.(in Chinese))
[20]SEED H B,REESE L C.The action of soft clay along friction piles[J].Transactions of the American Society of Civil Engineers,1957,122(1):731-754.
[21]KEZDI A.Bearing capacity of piles and pile groups[C]//Proceedings of the 4th International Conference of Soil Mechanics and Foundation Engineering.London:[s.n.],1957:46-51.
[22]KRAFT JR L,FOCHT JR J,AMERASINGHE S.Friction capacity of piles driven into clay[J].Journal of Geotechnical and Geoenvironmental Engineering,1981,107(11):1 521-1 541.
[23]COYLE H M,REESE L C.Load transfer for axially loaded piles in clay[J].Journal of the Soil Mechanics and Foundations Division,1966,92(2):1-26.
[24]COYLE H M,SULAIMAN I H.Skin friction for steel piles in sand[J].Journal of Soil Mechanics and Foundations Div.,1967,93(6):261-272.
[25]VIJAYVERGIYA V.Load movement characteristics of piles[C]//Proceedings of the Ports 77 Conference.Lifornia:[s.n.],1977:269-284.
[26]ISENHOWER W M,WANG S T,SQUEZ L G.Technical manual for L pile 2016[M].Austin:Ensoft,Inc.,2016:82-83.
[27]PISA Academic Work Group(University of Oxford,Imperial College London,University College Dublin).PISA Final Report[R].Fredericia:DONG Energy,2016:119.
[28]HALDAR S,SHARMA J,BASU D.Probabilistic analysis of monopile-supported offshore wind turbine in clay[J].Soil Dynamics and Earthquake Engineering,2018,105:171-183.
[29]李洪江,刘松玉,童立元,等.小变形下考虑摩擦效应的桩基水平承载分析方法[J].岩石力学与工程学报,2018,37(1):230-238.(LIHongjiang,LIU Songyu,TONG Liyuan,et al.Method to analyze lateral bearing capacity of small deformation piles considering friction effect[J].Chinese Journal of Rock Mechanics and Engineering,2018,37(1):230-238.(in Chinese))
[2]塞尔瓦杜雷A P S.土与基础相互作用的弹性分析[M].范文田,何广汉,张式深,等译.北京:中国铁道出版社,1981:8.(SELVADURAL A P S.Elastic analysis of soil-foundation interaction[M].Translated by the FAN Wentian,HE Guanghan,ZHANG Shishen,et al.Beijing:China Railway Press,1981:8.(in Chinese))
[3]MCCLELLAND B,FOCHT J A.Soil modulus for laterally loaded piles[J].Transactions of the American Society of Civil Engineers,1958,123(1):1 049-1 063.
[4]REESE L C,COX W R,KOOP F D.Analysis of laterally loaded piles in sand[C]//Proceedings of 6th Annual Offshore Technology Conference.Dallas:[s.n.],1974:473-483.
[5]O′NEIL M W,MURCHISON J M.An evaluation of p-y relationships in sand[R].[S.l.]:Report of the American Petroleum Institute,1983.
[6]MURCHISON J M,O'NEILL M W.Evaluation of py relationships in cohesionless soils[C]//Analysis and Design of Pile Foundations.[S.l.]:[s.n.],1984:174-191.
[7]GEORGIADIS M,ANAGNOSTOPOULOS C,SAFLEKOU S.Centrifugal testing of laterally loaded piles in sand[J].Canadian Geotechnical Journal,1992,29(2):208-216.
[8]王国粹,杨敏.砂土中水平受荷桩非线性分析[J].岩土力学,2011,32(增2):261-267.(WANG Guocui,YANG Min.Nonlinear analysis of laterally loaded piles in sand[J].Rock and Soil Mechanics,2011,32(Supp.2):261-267.(in Chinese))
[9]MATLOCK H.Correlation for design of laterally loaded piles in soft clay[C]//Offshore Technology in Civil Engineering.[S.l.]:[s.n.],1970:77-94.
[10]REESE L C,WELCH R C.Lateral loading of deep foundations in stiff clay[J].Journal of Geotechnical and Geoenvironmental Engineering,1975,101(7):633-649.
[11]American Petroleum Institute.ISO 19901 Geotechnical and foundation design considerations[S].Washington,D.C.:American Petroleum Institute Publishing Services,2014.
[12]DNV GL Group.DNVGL-ST-0126,Support structures for wind turbines[S].Oslo:Det Norske Veritas,2016.
[13]中华人民共和国行业标准编写组.JTS 167-4-2012港口工程桩基规范[S].北京:人民交通出版社,2012.(The Professional Standards Compilation Group of People′s Republic of China.JTS167-4-2012Code for pile foundation of harbor engineering[S].Beijing:China Communications Press,2012.(in Chinese))
[14]FINN W L,DOWLING J.Modelling effects of pile diameter[J].Canadian Geotechnical Journal,2015,53(1):173-178.
[15]ALIKHANLOU F.A discrete model for the analysis of short pier foundations in clays[M.S.Thesis][D].[S.l.]:Annals of the Rheumatic Diseases,1981.
[16]ASHOUR M,HELAL A.Contribution of vertical skin friction to the lateral resistance of large-diameter shafts[J].Journal of Bridge Engineering,2014,19(2):289-302.
[17]BYRNE B W,MCADAM R,BURD H J,et al.New design methods for large diameter piles under lateral loading for offshore wind applications[C]//International Symposium on Frontiers in Offshore Geotechnics.Oslo:CRC Press,2015:705-710.
[18]LI W,ZHU B,YANG M.Static response of monopile to lateral load in overconsolidated dense sand[J].Journal of Geotechnical and Geoenvironmental Engineering,2017,143(7):04017026.
[19]王勖成.有限单元法[M].北京:清华大学出版社,2003:311-315.(WANG Xucheng.Finite element method[M].Beijing:Tsinghua University Press,2003:311-315.(in Chinese))
[20]SEED H B,REESE L C.The action of soft clay along friction piles[J].Transactions of the American Society of Civil Engineers,1957,122(1):731-754.
[21]KEZDI A.Bearing capacity of piles and pile groups[C]//Proceedings of the 4th International Conference of Soil Mechanics and Foundation Engineering.London:[s.n.],1957:46-51.
[22]KRAFT JR L,FOCHT JR J,AMERASINGHE S.Friction capacity of piles driven into clay[J].Journal of Geotechnical and Geoenvironmental Engineering,1981,107(11):1 521-1 541.
[23]COYLE H M,REESE L C.Load transfer for axially loaded piles in clay[J].Journal of the Soil Mechanics and Foundations Division,1966,92(2):1-26.
[24]COYLE H M,SULAIMAN I H.Skin friction for steel piles in sand[J].Journal of Soil Mechanics and Foundations Div.,1967,93(6):261-272.
[25]VIJAYVERGIYA V.Load movement characteristics of piles[C]//Proceedings of the Ports 77 Conference.Lifornia:[s.n.],1977:269-284.
[26]ISENHOWER W M,WANG S T,SQUEZ L G.Technical manual for L pile 2016[M].Austin:Ensoft,Inc.,2016:82-83.
[27]PISA Academic Work Group(University of Oxford,Imperial College London,University College Dublin).PISA Final Report[R].Fredericia:DONG Energy,2016:119.
[28]HALDAR S,SHARMA J,BASU D.Probabilistic analysis of monopile-supported offshore wind turbine in clay[J].Soil Dynamics and Earthquake Engineering,2018,105:171-183.
[29]李洪江,刘松玉,童立元,等.小变形下考虑摩擦效应的桩基水平承载分析方法[J].岩石力学与工程学报,2018,37(1):230-238.(LIHongjiang,LIU Songyu,TONG Liyuan,et al.Method to analyze lateral bearing capacity of small deformation piles considering friction effect[J].Chinese Journal of Rock Mechanics and Engineering,2018,37(1):230-238.(in Chinese))