风机梁板式桩筏基础承载特性大型模型试验研究
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摘要
梁板式桩筏基础与传统桩筏基础一样具有较高的承载力和变形控制能力,且较传统桩筏基础能够节约成本,具有重要经济效应,因而成为了新兴的基础形式被应用于风电基础中。然而目前该基础仍采用传统桩筏基础的设计方法进行计算,造成了巨大的浪费。为了弥补目前梁板式风机基础设计方法的缺陷,采用大型室内模型试验对梁板式风机基础的受力变形特性进行研究,分析了竖向荷载作用下梁板式风机基础内梁、桩、土体等的受力机制及特性。研究表明,在工作荷载范围内,梁板式桩筏基础体系处于弹性状态,且梁板式桩筏基础具有一定的柔性,中央与边缘存在一定的差异沉降。桩-桩相互作用及桩-土相互作用对具有一定柔性的梁板式桩筏基础受力变形特性具有重大的影响,应该修正现行设计时不考虑这几个因素的缺点。
The piled beam-slab foundation is a new type of foundations for the wind turbine on land. The bearing capacity and the ability of deformation control of the piled beam-slab foundation are as good as those of the traditional pile-raft foundation. Compared with the traditional pile-raft foundation or the gravity foundation, it is popular for its great advantage in cost savings. Unfortunately, the piled beam-slab foundation is still designed according to the design method for traditional pile-raft foundation since now, which leads to a waste of money. In order to develop a reasonable design method for the piled beam-slab foundation, a large-scale model test is carried out to study the deformation characteristics and the mechanical property of the piled beam-slab foundation under vertical load. The study shows that the behavior of the piled beam-slab foundation system is elastic under the working load. A significant differential settlement occurs between the centre and the edge of the foundation. The pile-pile interaction and the pile-soil interaction which are not considered in the present design method have significant impacts on the behavior of the piled beam-slab foundation. Thus, it should be considered in the future design.
The piled beam-slab foundation is a new type of foundations for the wind turbine on land. The bearing capacity and the ability of deformation control of the piled beam-slab foundation are as good as those of the traditional pile-raft foundation. Compared with the traditional pile-raft foundation or the gravity foundation, it is popular for its great advantage in cost savings. Unfortunately, the piled beam-slab foundation is still designed according to the design method for traditional pile-raft foundation since now, which leads to a waste of money. In order to develop a reasonable design method for the piled beam-slab foundation, a large-scale model test is carried out to study the deformation characteristics and the mechanical property of the piled beam-slab foundation under vertical load. The study shows that the behavior of the piled beam-slab foundation system is elastic under the working load. A significant differential settlement occurs between the centre and the edge of the foundation. The pile-pile interaction and the pile-soil interaction which are not considered in the present design method have significant impacts on the behavior of the piled beam-slab foundation. Thus, it should be considered in the future design.
引文
[1]连柯楠,木林隆,黄茂松,等.国华通辽风电场三期工程梁板式桩筏基础性状数值分析[J].岩土力学,2012,33(增刊1):290-296.LIAN Ke-nan,MU Lin-long,HUANG Mao-song,et al.Finite element analysis for piled beam-slab foundation of the third-phase project of Guohua Tongliao wind farms[J].Rock and Soil Mechanics,2012,33(Supp.1):290-296.
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[9]MU Lin-long,HUANG Mao-song,LIAN Ke-nan.Analysis of pile-raft foundations under complex loads in layered soils[J].International Journal for Numerical and Analytical Methods in Geomechanics,2014,38(3):256-280.
[10]SANCTIS L,MANDOLINI A.Bearing capacity of piled rafts on soft clay soils[J].Journal of Geotechnical and Geoenvironmental Engineering,2006,132(12):1600-1610.
[11]董建国,赵锡宏.高层建筑地基基础——共同作用理论与实践[M].上海:同济大学出版社,1997.
[12]HORIKOSHI K,RANDOLPH M E.Centrifuge modelling of piled raft foundations on day[J].Geotechnique,1996,6(4):741-752.
[13]HUANG Mao-song,MU Lin-long.Vertical response of pile-raft foundations subjected to tunnelling-induced ground movements in layered soil[J].International Journal for Numerical and Analytical Methods in Geomechanics,2012,36(8):977-1001.
[2]江书超.梁板式基础工作性状试验研究[D].北京:中国建筑科学研究院,2012.
[3]KUWABARA F.An elastic analysis of piled raft foundations in a homogeneous soil[J].Engineering Structures,1989,29(1):81-92.
[4]MENDONCA A V,PAIVA J B.An elastostatic FEM/BEM analysis of vertically loaded raft foundation on piles[J].Engineering Analysis with Boundary Elements,2003,24(3):237-247.
[5]SHEN W Y,CHOW Y K,YONG K Y.A variational approach for the analysis of pile group-pile cap interaction[J].Geotechnique,2000,50(4):349-357.
[6]CHOW Y K,YONG K Y,SHEN W Y.Analysis of piled raft foundation using a variational approach[J].International Journal of Geomechanics,2001,1(2):129-147.
[7]RANDOLPH M F,WROTH C P.Analysis of deformation of vertically loaded piles[J].Journal of the Geotechnical Engineering Division,1978,104(12):1465-1488.
[8]POULOS H G,DAVIS E H.Pile foundation analysis and design[M].New York:John Wiley and Sons,1980.
[9]MU Lin-long,HUANG Mao-song,LIAN Ke-nan.Analysis of pile-raft foundations under complex loads in layered soils[J].International Journal for Numerical and Analytical Methods in Geomechanics,2014,38(3):256-280.
[10]SANCTIS L,MANDOLINI A.Bearing capacity of piled rafts on soft clay soils[J].Journal of Geotechnical and Geoenvironmental Engineering,2006,132(12):1600-1610.
[11]董建国,赵锡宏.高层建筑地基基础——共同作用理论与实践[M].上海:同济大学出版社,1997.
[12]HORIKOSHI K,RANDOLPH M E.Centrifuge modelling of piled raft foundations on day[J].Geotechnique,1996,6(4):741-752.
[13]HUANG Mao-song,MU Lin-long.Vertical response of pile-raft foundations subjected to tunnelling-induced ground movements in layered soil[J].International Journal for Numerical and Analytical Methods in Geomechanics,2012,36(8):977-1001.