ارزیابی قابلیت استفاده از مهارهای چندصفحه‌ای بازشونده در خاک‌های دانه‌ای سست و متراکم

نوع مقاله : مقاله پژوهشی

نویسندگان

گروه ژئوتکنیک، دانشکده مهندسی عمران و منابع زمین، واحد تهران مرکزی، دانشگاه آزاد اسلامی، تهران، ایران

چکیده

امروزه بشر برای تأمین انرژی به فکر ایجاد سازه‌ها و سکوهایی بر روی دریا و خشکی افتاده است. تاکنون مهارهای مختلفی با شکل‌های متفاوت به‌منظور استحکام و پایداری سازه‌ها، برای استفاده در دریا و خشکی معرفی‌شده است. یکی از مهارهای جدید معرفی‌شده در زمینه ژئوتکنیک دریایی، مهارهای صفحه‌ای بازشو هستند که در مقایسه با مهارهای رایج مورداستفاده دیگر دارای مزیت‌های مهمی نظیر نصب، قفل و فعال‌شدگی در خاک با نیروی کمتر می‌باشند. ازآنجایی‌که این مهارها به‌تازگی توسعه داده‌شده‌اند، عملکرد این مهارها تحت اثر شرایط مختلف به‌طور کامل موردبررسی قرار نگرفته است. بنابراین در این تحقیق، رفتار مهارهای چندصفحه‌ای باقابلیت باز شوندگی صفحات در خاک و میزان ظرفیت باربری آن‌ها با استفاده از مدلسازی آزمایشگاهی موردبررسی قرارگرفته است. تأثیر پارامترهای مختلف مانند میزان تراکم خاک و تأثیر فاصله صفحات از یکدیگر بر سرعت بازشدگی صفحات در خاک، عمق فعال‌شدگی نهایی مسلح کننده‌ها و ظرفیت باربری نهایی مهار بررسی‌شده است. در ابتدا مهار تک‌صفحه‌ای با مهار معادل دوصفحه‌ای با مساحت یکسان مورد مقایسه قرارگرفته است. سپس عملکرد مهار دوصفحه‌ای در 5 تراکم مختلف در آزمایشگاه موردبررسی قرارگرفته است نتایج به‌دست‌آمده نشان داد که در تراکم‌های بالا، مهار‌های تک‌صفحه‌ای دارای ظرفیت باربری بیشتری در مقایسه با مهارها دوصفحه‌ای بودند. همچنین به‌طور معکوس، مهارهای صفحه‌ای دوتایی دارای ظرفیت باربری بیشتری نسبت به مهارهای صفحه‌ای تکی در  خاک‌های با تراکم پایین‌تر بودند. علاوه بر این میزان تأثیر 4 فاصله بین صفحات مهار دوصفحه‌ای بر روی ظرفیت باربری نهایی مهار موردبررسی قرارگرفته و بر اساس نتایج به‌دست‌آمده تأثیر تغییر فاصله صفحات به‌مراتب بیشتر از تأثیر تغییر تراکم خاک بوده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluating the Capacity of the Multi-Plate Mechanical Anchors in Granular Soils

نویسندگان [English]

  • Hamid Reza Mohammadkhanifard
  • Amir Ali Zad
  • Mahsa Amjadi
B.Sc., M.Sc., Department of Civil Engineering, Faculty of Civil Engineering and Earth Resources, Islamic Azad University, Central Tehran Branch, Tehran, Iran,
چکیده [English]

Nowadays, humans have thought of creating structures and platforms onshore and offshore to provide energy. Until now, various anchors with different shapes have been introduced for strength and stability of platforms, for offshore and onshore applications. In this research, a new type of expendable multi-plate anchors is proposed with the ability to expand the plates in the soil with lower energy. As these anchors are recently introduced, their bearing capacity has not been extensively evaluated. In this research, the behavior of these anchors was investigated experimentally. The evaluated parameters are soil compaction and distance between plates on the maximum pull-out capacity of them. Firstly the performance of single plate anchors was compared with the double plate anchors with equivalent areas then the effect of above mentioned parameters was determined for double plate anchors Based on the experimental results, single-plate shows higher bearing capacity in high soil compaction, but in low soil compaction, the bearing capacity of the double plate capacity is increased. The effect of the distance between the plates on the final bearing capacity has been far greater than the effect of the change in soil density. Also, 4 different soil compaction and distance between two plates for a double plate were investigated. Overall the effects of distance between two plates have more impact on bearing capacity in comparison to soil compaction

کلیدواژه‌ها [English]

  • Multi-Plate Mechanical Anchor
  • Onshore and Offshore, Expandable Plate Anchors. Soil Compaction
[1] R.L. Copstead, D.D. Studier, An earth anchor system: installation and design guide,  (1990).
[2] J.T. Shelton, OMNI-Maxtrade anchor development and technology, in:  OCEANS 2007, IEEE, 2007, pp. 1-10.
[3] M. Randolph, S. Gourvenec, D. White, M. Cassidy, Offshore geotechnical engineering, Spon Press New York, 2011.
[4] B.M. Das, S.K. Shukla, Earth anchors, J. Ross Publishing, 2013.
[5] C. Gaudin, C. O’Loughlin, M. Randolph, M. Cassidy, D. Wang, Y. Tian, J. Hambleton, R. Merifield, Advances in offshore and onshore anchoring solutions, Australian Geomechanics, 49(4) (2014) 59-72.
[6] C. O’Loughlin, A. Blake, M. Richardson, M. Randolph, C. Gaudin, Installation and capacity of dynamically embedded plate anchors as assessed through centrifuge tests, Ocean Engineering, 88 (2014) 204-213.
[7] C. O'Loughlin, D. White, S. Stanier, Novel anchoring solutions for FLNG-Opportunities driven by scale, in:  Offshore Technology Conference, Offshore Technology Conference, 2015.
[8] A. Ghaly, A. Hanna, M. Hanna, Uplift behavior of screw anchors in sand. I: dry sand, Journal of Geotechnical Engineering, 117(5) (1991) 773-793.
[9] A.J. Lutenegger, Behavior of multi-helix screw anchors in sand, in:  Proceedings of the 14th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, Toronto, Ont.[CD ROM], 2011.
[10] C.d.H.C. Tsuha, N. Aoki, G. Rault, L. Thorel, J. Garnier, Evaluation of the efficiencies of helical anchor plates in sand by centrifuge model tests, Canadian Geotechnical Journal, 49(9) (2012) 1102-1114.
[11] S. Mittal, S. Mukherjee, Vertical uplift capacity of a group of helical screw anchors in sand, Indian Geotechnical Journal, 43(3) (2013) 238-250.
[12] B. Cerfontaine, J.A. Knappett, M.J. Brown, A.S. Bradshaw, Effect of soil deformability on the failure mechanism of shallow plate or screw anchors in sand, Computers and Geotechnics, 109 (2019) 34-45.
[13] J. Kumar, K. Kouzer, Vertical uplift capacity of a group of shallow horizontal anchors in sand, Géotechnique, 58(10) (2008) 821-823.
[14] M. Yang, C.P. Aubeny, J.D. Murff, Behavior of suction embedded plate anchors during keying process, Journal of Geotechnical and Geoenvironmental Engineering, 138(2) (2012) 174-183.
[15] A. Bera, U. Banerjee, Uplift capacity of model bell shaped anchor embedded in sand, International Journal of Geotechnical Engineering, 7(1) (2013) 84-90.
[16] B.D. Diaz, M. Rasulo, C.P. Aubeny, C.M. Fontana, S.R. Arwade, D.J. DeGroot, M. Landon, Multiline anchors for floating offshore wind towers, in:  OCEANS 2016 MTS/IEEE Monterey, IEEE, 2016, pp. 1-9.
[17] G. Spagnoli, C. de Hollanda Cavalcanti Tsuha, P. Oreste, C. Mauricio Mendez Solarte, Estimation of uplift capacity and installation power of helical piles in sand for offshore structures, Journal of Waterway, Port, Coastal, and Ocean Engineering, 144(6) (2018) 04018019.
[18] F. Liang, H. Zheng, H. Zhang, On the pile tension capacity of scoured tripod foundation supporting offshore wind turbines, Applied Ocean Research, 102 (2020) 102323.
[19] S. Vicent, S.-R. Kim, Evaluation of horizontal and vertical bearing capacities of offshore bucket work platforms in sand, Applied Ocean Research, 101 (2020) 102198.
[20] V. Bolandnazar, M. Hajialilue, J. Safadost, Experimental investigation bearing pull-out of single and grupe multi plate anchors in granular soil, in:  The fourth national conference of geotechnical engineering of Iran 1398 (in persian).
[21] N. Dastaran , M. Jalali Moghadam , A. Zad, Introduction and Determination of the New Generation of Mechanical Anchors for Using As a Geotechnical Supporting System Journal of civil and environmental engineering of Tabriz University, 51.3(104) (2021) 55-66 (in persian).
[22] A. Roy, S.H. Chow, M.F. Randolph, C.D. O'loughlin, Consolidation effects on uplift capacity of shallow horizontal plate anchors in dilating sand, Géotechnique, 72(11) (2022) 957-973.
[23] A. Roy, C.D. O'loughlin, S.H. Chow, M.F. Randolph, Inclined loading of horizontal plate anchors in sand, Géotechnique, 72(12) (2022) 1051-1067.
[24] Y.-X. Gao, H.-H. Zhu, Y.-F. Ni, C. Wei, B. Shi, Experimental study on uplift behavior of shallow anchor plates in geogrid-reinforced soil, Geotextiles and Geomembranes, 50(5) (2022) 994-1003.
[25] S. Ravishankar, S. Banerjee, Sarvesh, S. Mukherjee, Static, cyclic, and post-cyclic pullout response of horizontal plate anchors in reinforced soft clay, International Journal of Geosynthetics and Ground Engineering, 8(3) (2022) 37.
[26] P.-Z. Zhuang, H.-Y. Yue, X.-G. Song, H. Yang, H.-b. Zhang, H.-S. Yu, Pullout behaviour of inclined shallow plate anchors in sand, Canadian Geotechnical Journal, 59(2) (2022) 239-253.
[27] V.B. Tilak, N.K. Samadhiya, Pullout capacity of Circular Multi-plate Inclined Anchors in Sand: An Experimental Study, Geotechnical and Geological Engineering, 41(4) (2023) 2427-2449.
[28] L. Zhao, X. Gong, S. Hu, Y. Tan, Z. Zhao, Effects of Heterogeneity and Nonlinearity on Uplift Characteristics of Shallow Horizontal Anchor Plates, Geotechnical and Geological Engineering, 41(2) (2023) 1615-1634.
[29] M. Amjadi, H.R. Mohammadkhanifard, A. Tohidi, A. Zad, Comparing pull-out capacity of expandable anchors using discrete/coupled Eulerian element methods versus finite element technique, Marine Georesources & Geotechnology,  (2023) 1-16.
[30] M.j. Moghadam, N. Dastaran, A. Zad, Introducing expandable mechanical plate anchors for onshore and offshore anchoring,  (2021).
[31] A. Bradshaw, J. Giampa, H. Gerkus, S. Jalilvand, J. Fanning, S. Nanda, R. Gilbert, K. Gavin, V. Sivakumar, Scaling considerations for 1-g model horizontal plate anchor tests in sand, Geotechnical Testing Journal, 39(6) (2016) 1006-1014.
[32] S.T.M.f.M.I.D.a.U.W.o.S.a.C.o.R.D. ASTM D4254-16, ASTM International, West Conshohocken, PA, 2016, www.astm.org, in, 2016.
[33] S.T.M.f.M.I.D.a.U.W.o.S.U.a.V.T. ASTM D4253-16e1, ASTM International, West Conshohocken, PA, 2016, www.astm.org, in, 2016.
[34] S.T.M.f.D.S.T.o.S.U.C.D.C. ASTM D3080-04, ASTM International, West Conshohocken, PA, 2004, www.astm.org, in, 2004.
[35] M.E. Bychkowski, Pullout resistance of soil anchors in cohesionless soil under varying velocities by experimental methods,  (2016).
[36] W.H. Baker, R.L. Konder, Pullout load capacity of a circular earth anchor buried in sand, Highway Research Record, (108) (1966).
[37] M.S. Keskin, Model studies of uplift capacity behavior of square plate anchors in geogrid-reinforced sand, Geomechanics & engineering, 8(4) (2015) 595-613.