海上风机筒型基础黏土地基离心模型试验研究
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摘要
在海洋工程基础设计中,筒型基础得到越来越广泛的应用。多为饱和淤泥质土的海洋工程地基受力环境复杂,利用离心机用较小模型可再现原型应力的特点,采用清华大学50 g·t离心机对饱和淤泥质土地基上筒型基础模型进行了离心模型试验。基于试验结果分析了水平荷载施加过程中基础和地基的变形和受力特性,以及基础周围地基中孔压的变化。基础上作用有水平静推力和风机循环荷载,若静推力和循环荷载的幅值之和不超过临塑荷载,循环荷载对基础变形影响有限,若超过临塑荷载,长期循环荷载作用造成的地基累积变形使筒与地基脱开,从而造成筒与地基间吸力逐渐丧失,基础发生倾倒破坏。
The bucket foundation is widely used in ocean engineering. Most of the ocean foundations are in saturated mucky soil, meanwhile, they suffer from the complex stress environment. A series of centrifugal model tests are conducted in the bucket foundation on the saturated mucky soil to simulate the prototype stress in the foundation. Based on the analysis of the typical tests, the stress and deformation and pore pressure characteristics of the foundation are introduced under cyclic horizontal loading conditions. The horizontal static and cyclic loadings are conducted on the foundation. If the total load exceeds the critical plastic one of the foundation, its deformation is negligible, or else the accumulated deformation formed by the long-term cyclic loading makes the bucket and the ground be apart, which will cause the loss of the suction and the dumping of the bucket foundation.
The bucket foundation is widely used in ocean engineering. Most of the ocean foundations are in saturated mucky soil, meanwhile, they suffer from the complex stress environment. A series of centrifugal model tests are conducted in the bucket foundation on the saturated mucky soil to simulate the prototype stress in the foundation. Based on the analysis of the typical tests, the stress and deformation and pore pressure characteristics of the foundation are introduced under cyclic horizontal loading conditions. The horizontal static and cyclic loadings are conducted on the foundation. If the total load exceeds the critical plastic one of the foundation, its deformation is negligible, or else the accumulated deformation formed by the long-term cyclic loading makes the bucket and the ground be apart, which will cause the loss of the suction and the dumping of the bucket foundation.
引文
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[2]罗承先.世界风力发电现状与前景预测[J].中外能源,2012,17(3):24–31.(LUO Cheng-xian.Wind power generation today in the world and prospect forecast[J].Sino-global Energy,2012,17(3):24–31.(in Chinese))
[3]HOULSBY G T,KELLY R B,HUXTABLE J,et al.Field trials of suction caissons in clay for offshore wind turbine foundations[J].Géotechnique,2005,55(4):287–296.
[4]HOULSBY G T,KELLY R B,HUXTABLE J,et al.Field trials of suction caissons in sand for offshore wind turbine foundation[J].Géotechnique,2006,56(1):3–10.
[5]刘锟,赵春风,王建华.软土地基桶形基础室内模型试验研究[J].地下空间与工程学报,2010,6(3):477–480.(LIU Kun,ZHAO Chun-feng,WANG Jian-hua.Model test study of bucket foundation on soft clay strata[J].Chinese Journal of Underground Space and Engineering,2010,6(3):477–480.(in Chinese))
[6]黄维平,刘建军,赵战华.海上风电基础结构研究现状及发展趋势[J].海洋工程,2009,27(2):130–134.(HUANG Wei-ping,LIU Jian-jun,ZHAO Zhan-hua.The state of the art of study on offshore wind turbine structures and its development[J].The Ocean Engineering,2009,27(2):130–134.(in Chinese))
[7]鲁晓兵,王义华,张建红,等.水平动载下桶形基础变形的离心机试验研究[J].岩土工程学报,2005,27(7):789–791.(LU Xiao-bing,WANG Yi-hua,ZHANG Jian-hong,et al.Centrifuge test on the deformation of bucket foundation under horizontal vibration load[J].Chinese Journal of Geotechnical Engineering,2005,27(7):789–791.(in Chinese))
[8]荣冰,张嘎,王富强.离心场中风力电机桩基复杂加载测试设备的研制[J].岩土力学,2011,32(5):1596–1600.(RONG Bing,ZHANG Ga,WANG Fu-qiang.Complicated loading device for pile foundation of wind-driven generator in centrifugal field[J].Rock and Soil Mechanics,2011,32(5):1596–1600.(in Chinese))
[9]ZHANG G,HU Y,ZHANG J M.New image-analysis-based displacement-measurement system for centrifuge modeling tests[J].Measurement,2009,42(1):87–96.