|
|
|
| Centrifugal model tests on cyclic uplift performance of wished-in-place helical anchors in dense sand |
| HAO Dongxue1，CHEN Rong1，YUAN Chi1，2，KONG Gangqiang3，SHI Danda4 |
| (1. School of Civil Engineering and Architecture，Northeast Electric Power University，Jilin，Jilin 132012，China；2. College of Architecture and Civil Engineering，Beijing University of Technology，Beijing 100124，China；3. Key Laboratory of Geomechanics and Embankment Engineering，Ministry of Education，Hohai University，Nanjing，Jiangsu 210098，China；4. College of Ocean Science and Engineering，Shanghai Maritime University，Shanghai 201306，China) |
|
|
|
|
Abstract Helical anchors have been widely used to support the structures suffering from cyclic uplift loading，such as wind turbines and transmission towers，due to their good uplift resistance. And the studies on cyclic performance of helical anchors are limited. Therefore，centrifugal tests of helical anchors(wished-in-place) in dense sand under cyclic loading were conducted to investigate the effects of embedment ratio and number of helices on cyclic uplift stability and cyclic capacity. Test results show that the uplift displacements at the beginning of ultimate cyclic loading level are very close to the failure displacements under monotonic loading for single-helix anchors. Relative ultimate cyclic uplift capacity for single-helix anchor increases gradually with the increase of embedment ratio H/D and reaches the maximum value 0.9 at the embedment ratio of 6，and then the value of almost keeps constant when embedment ratio is more than 6. Moreover，the relative accumulated displacements during each cyclic loading for single-helix anchors with embedment ratio less than 6 are all higher than the anchors with embedment ratio more than 6. Therefore，minimum embedment ratio for single-helix anchor is proposed as 6 when it is used to resist cyclic uplift loading. The relative ultimate cyclic uplift capacity of double-helix anchor is the same as that of single-helix anchor with the same embedment ratio，but the accumulated displacements during each cyclic loading for double-helix anchor are all less than those values for single-helix anchor. Double-helix anchor should have higher cyclic uplift capacity than single-helix anchor if displacement is taken as control condition.
|
|
|
|
|
|
| [1] TSUHA C H C，AOKI N，RAULT G，et al. Evaluation of the efficiencies of helical anchor plates in sand by centrifuge model tests[J]. Canadian Geotechnical Journal，2012，49(8)：1 102–1 114.
[2] MERIFIELD R S. Ultimate uplift capacity of multiplate helical type anchors in clay[J]. Journal of Geotechnical and Geoenvironmental Engineering，ASCE，2011，137(7)：704–716.
[3] LUTENEGGER A J. Behavior of multi-helix screw anchors in sand[C]// 2011 Pan-Am CGS Geotechnical Conference. [S. l.]：[s. n.]，2011：1–6.
[4] WADA M，TOKIMATSU K，MARUYAMA S，et al. Effects of cyclic vertical loading on bearing and pullout capacities of piles with continuous helix wing[J]. Soils and Foundations，2017，57(1)：141–153.
[5] SCHIAVON J A，TSUHA C H C，THOREL L. Cyclic and post-cyclic monotonic response of a single-helix anchor in sand[J]. Géotechnique Letters，2017：7(2)：1–7.
[6] 中华人民共和国行业标准编写组. Q/GDW 584—2011 架空输电线路螺旋锚基础设计技术规范[S]. 北京：中国电力出版社，2011. (The Professional Standards Compilation Group of People′s Republic of China. Q/GDW 584—2011 Technical regulation for design screwanchor foundation of overhead transmission line[S]. Beijing：China Electric Power Press，2011.(in Chinese))
[7] CLEMENCE S P，SMITHLING A P. Dynamic uplift capacity of helical anchors in sand[C]// Proceedings of 4th Australia–New Zealand conference on geomechanics. Perth，Australia：[s. n.]，1984：88–93.
[8] CERATO A B，VICTOR R. Effects of helical anchor geometry on long-term performance of small wind tower foundations subject to dynamic loads[J]. The Journal of the Deep Foundations Institute，2008，2(1)：30–41.
[9] CERATO A B，VICTOR R. Effects of long-term dynamic loading and fluctuating water table on helical anchor performance for small wind tower foundations[J]. Journal of Performance of Constructed Facilities，ASCE，2009，23(4)：251–261.
[10] BUHLER R，CERATO A B. Design of dynamically wind–loaded helical piers for small wind turbines[J]. Journal of Performance of Constructed Facilities，ASCE，2010，24(4)：417–426.
[11] SHARNOUBY M M E，NAGGAR M H E. Field investigation of axial monotonic and cyclic performance of reinforced helical pulldown micropiles[J]. Canadian Geotechnical Journal，2012，49(4)：560–573.
[12] SHARNOUBY M M E，NAGGAR M H E. Axial monotonic and cyclic performance of fibre-reinforced polymer(FRP)-steel fibre-reinforced helical pulldown micropiles(FRP-RHPM)[J]. Canadian Geotechnical Journal，2012，49(11)：1 378–1 392.
[13] SCHIAVON J A，TSUHA C H C，NEEL A，et al. Centrifuge modelling of a helical anchor under different cyclic loading conditions in sand[J]. International Journal of Physical Modelling in Geotechnics，2019，19(2)：72–88.
[14] SCHIAVON J A，TSUHA C H C，THOREL L. Monotonic，cyclic and post-cyclic performances of single-helix anchor in residual soil of sandstone[J]. Journal of Rock Mechanics and Geotechnical，2019，11(4)：824–836.
[15] 郝冬雪，陈 榕，符胜男，砂土中螺旋锚上拔承载特性模型试验研究[J]. 岩土工程学报，2015，37(1)：126–132.(HAO Dongxue，CHEN Rong，FU Shengnan. Experimental study on uplift capacity of multi-helix anchors in sand[J]. Chinese Journal of Geotechnical Engineering，2015，37(1)：126–132.(in Chinese))
[16] ILAMPARUTHI K，DICKIN E A，MUTHUKRISNAIAH K. Experimental investigation on the uplift capacity of circular anchors in sand[J]. Canadian Geotechnical Journal，2002，39(5)：648–664.
[17] HAO D X，WANG D，O'LOUGHLIN，C D，et al. Tensile monotonic capacity of helical anchors in sand：interaction between helices[J]. Canadian Geotechnical Journal，2019，56(10)：1 534–1 543.
[18] Technical Design Manual Compilation Group. Technical design manual[M]. 4th ed [S. l.]：Hubbell Power Systems，Inc.，2018：5–7.
[19] CLAYTON D J. Utility industry anchor design and maintenance manual[R]. [S. l.]：Earth Contact Products LLC，2011.
[20] OVESEN N K. The use of physical models in design：The scaling law relationships[C]// Proceedings of the Seventh European Conference on Soil Mechanics and Foundation Engineering. Brighton，United Kingdom：[s.n.]，1979：318–323.
[21] LIU J Y，LIU M L，ZHU Z. Sand deformation around an uplift plate anchor[J]. Journal of Geotechnical and Geoenvironmental Engineering，ASCE，2012，138(6)：728–737.
[22] WHITE D J，CHEUK C Y，BOLTON M D. The uplift resistance of pipes and plate anchors buried in sand[J]. Geotechnique，2008，58(10)：771–779.
[23] 包承纲，饶锡保. 土工离心模型的试验原理[J]. 长江科学院院报，1998，15(2)：2–5.(BAO Chenggang，RAO Xibao. Principle of the geotechnical centrifuge model test[J]. Journal of Yangtze River Scientific Research Institute，1998，15(2)：2–5.(in Chinese))
|
|
|
|
2021, Vol. 40 
