Undrained uplift bearing capacity of suction bucket foundations under inclined loads
SUN Li-qiang1, XING Xiao-jia1, ZHAI Xue-li2, WU Xiong-zhi2, WANG Rong3
1. School of Civil Engineering, Tianjin University, Tianjin 300354, China; 2. College of Civil Engineering, Hebei University of Engineering, Handan 056038, China; 3. China Horbor LLC, Beijing 100027, China
Abstract:Aiming at the problem that the suction force of the suction bucket affects its bearing characteristics during the working process, the suction bucket is required to bear the uplift force of floating structures. Its bearing characteristics are related to the geometrical size of the suction bucket, the strength of the soil layer, the load characteristics and other factors. The bearing characteristics of suction bucket foundations under inclined loads under different aspect ratios and strength distributions are studied based on the finite element method. The relationship among vertical, horizontal bearing capacity coefficient and diameter ratio (L/D) and heterogeneity coefficient of soils K is established. The relevant method is also given. The envelope of vertical load (V) and horizontal load (H) is established, and the method for calculating the bearing capacity under the V-H combination is finally exhibited. The research results may provide a basis for the design of anti-pull-out foundation of marine floating structures.
[1] 武科, 栾茂田, 范庆来, 等. 竖向与水平复合加载下桶形基础承载性能的分析[J]. 岩土力学, 2006, 27(增刊2): 903-908. (WU Ke, LUAN Mao-tian, FAN Qing-lai, et al.Numerical analysis of bearing capacity behaviour of suction bucket foundations under joint loading condition of vertical and horizontal loads[J]. Rock and Soil Mechanics, 2006, 27(S2): 903-908. (in Chinese)) [2] 武科, 栾茂田, 范庆来. 竖向与水平荷载复合加载下桶形基础承载性能的分析[C]// 第一届中国水利水电岩土力学与工程学术讨论会论文集(下册), 2006, 昆明: 1042-1045. (WU Ke, LUAN Mao-tian, FAN Qing-lai, et al. Analysis of bearing capacity of bucket foundation under combined vertical and horizontal loads[C]// Papers of the First Sympo- sium on Geotechnical Mechanics and Engineering of Water Conserva- ncy and Hydropower in China (Volume 2), 2006, Kunming: 1042-1045. (in Chinese)) [3] WU Ke, LUAN Mao-tian, FAN Qing-lai, et al.Failure envelopes of bucket foundation subjected to combined loads[J]. Chinese Journal of Geotechnical Engineering, 2008, 30(4): 574-580. [4] GOURVENEC S, JENSEN K.Effect of embedment and spacing of cojoined skirted foundation systems on undrained limit states under general loading[J]. International Journal of Geomechanics, 2009, 9(6): 267-279. [5] GOURVENEC S, BARNETT S.Undrained failure envelope for skirted foundations under general loading[J]. Géotechnique, 2011, 61(3): 263-270. [6] GOURVENEC S.Effect of embedment on the undrained capacity of shallow foundations under general loading[J]. Géotechnique, 2015, 58(3): 177-185. [7] WATSON P G, RANDOLPH M F.Failure envelopes for caisson foundations in calcareous sediments[J]. Applied Ocean Research, 1998, 20(1): 83-94. [8] ZDRAVKOVIC L, 1'OTTS D M, JARDINE R J. A parametric study of the pull-out capacity of bucket foundations in soft clay[J]. Géotechnique, 2001, 51(1): 55-67. [9] MARTIN C M, HOULSBY G T.Combined loading of spudcan foundations on clay: laboratorytests[J]. Géotechnique, 2000, 50(4): 325-328. [10] MURFF J D, AUBENY C P, YANG M.The effect of torsion on the sliding resistance of rectangularfoundations[J]. Frontiers in Offshore Geotechnics II, 2010: 439-443. [11] BRANSBY M F, RANDOLPH M F.Combined loading of skirted foundations[J]. Géotechnique, 1998, 48(5): 637-655. [12] BRANSBY M F, RANDOLPH M F.The effect of embedment depth on the undrained response ofskirted foundations to combined loading[J]. Soils and Foundations, 1999, 39(4): 19-33. [13] 丁红岩, 王旭月, 张浦阳, 等. 砂土中宽浅式复合筒型基础三维包络面研究[J]. 太阳能学报, 2018, 39(4): 1097-1104. (DING Hong-yan, WANG Xu-yue, ZHANG Pu-yang, et al.Study of three-dimensional enveloping surface foundation in sandy soil[J]. Actaenergiaesolaris Sinica, 2018, 39(4):1097-1104. (in Chinese)) [14] AHN J, LEE H, KIM Y T.Holding capacity of suction caisson anchors embedded in cohesive soils based on finite element analysis[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2014, 38(15): 1541-1555. [15] 邱月, 高玉峰, 黎冰, 等. 倾斜荷载作用下沉箱基础的极限承载力计算方法[J]. 长江科学院院报, 2017, 34(6): 107-111. (QIU Yue, GAO Yu-feng, LI Bing, et al.Calculation methods for ultimate inclined bearing capacity of caisson foundation under inclined load[J]. Journal of Yangt-ze River Scientific Research Institute, 2017, 34(6): 107-111. (in Chinese)) [16] ISKANDER M, EL-GHARBAWY S, OLSON R.Performance of suction caissons in sand andclay[J]. Canadian Geotechnical Journal, 2002, 39(3): 576-584. [17] MARTIN C M. Vertical bearing capacity of skirted circular foundations on Tresca soil[C]// Proceedings of the 15th International Conference on Soil Mechanics and Geotechnical Engineering, 2001, Istanbul: 743-746. [18] SENDERS M, KAY S. Geotechnical suction pile anchor design in deep water soft clays[C]// 7th Annual Conference Deepwater Risers, Moorings & Anchorings, 2002, London.