معرفی و ارزیابی جامع نسل نوینی از مهار مکانیکی با قابلیت استفاده در پایدارسازی‌های ژئوتکنیکی

نوع مقاله : مقاله کامل پژوهشی

نویسندگان

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

چکیده

امروزه از انواع مختلف مهارهای خاکی و سنگی با ظرفیت‌های باربری و زمینه ­های کاربردی گوناگون در جهت تثبیت و تسلیح توده خاک ناپایدار و یا پایدارسازی و دوختن سازه ­ها در دریا و خشکی استفاده می­شود. در حالت کلی، مهارها به دو حالتِ نفوذیابنده و جای­گذاری شونده در محیط ­های خاکی و سنگی تقسیم می­شوند و می­توان آن­ها را به دو گروه اصلی مهارهای دوغابی و مهارهای مکانیکی تقسیم­بندی نمود. در این پژوهش نسل جدیدی از مهارهای مکانیکی به نام Expandable Mechanical Plate Anchors (EMPLAs) معرفی و ارزیابی گردیده است که با صرف کم­ترین هزینه و نیروی پیشرانه مورد نیاز برای نصب، در درون خاک نصب، قفل و فعال شده و مطابق با نتایج آزمایش‌های انجام شده دارای کارایی مناسبی در مهارها هستند. موارد مورد ارزیابی در این پژوهش شامل بررسی میزان اثرگذاری خصوصیات صفحات مهاری از قبیل شکل صفحات و میزان انحنای آن­ها بر روی مکانیزم قفل‌شدگی و میزان باربری نهایی مسلح کننده و نیز شدت زوال نیروی کششی تحت یک سرعت بیرون­کشش ثابت بوده است. طبق نتایج به­ دست آمده، شکل دایره­ای بهترین شکل و انحنای پایین صفحات هم بهترین زاویه برای افزایش ظرفیت باربری را دارا می­باشند.

کلیدواژه‌ها


عنوان مقاله [English]

Introduction and Determination of the New Generation of Mechanical Anchors for Using As a Geotechnical Supporting System

نویسندگان [English]

  • Nader Dastaran
  • Matin Jalali Moghadam
  • Amir Ali Zad
Geotechnical Engineering, School of Civil Engineering, Faculty of Engineering, Islamic Azad University Central Tehran Branch (IAUCTB)
چکیده [English]

So far, various methods have been reported for estimating the tensile bearing capacities using laboratory tests, software modeling, and estimation theory (Das and Shukla, 2013; Moghadam et al, 2018; Randolf , 2011). In the present study, different aspects of the mechanical behavior of EMPLAs are evaluated during the performed pullouts using experimental test and 3d numerical modelling. In addition, the effect of the properties of anchor plates such as their shape and curvature on locking speed of expandable plates in the soil, and activation of anchors, as well as the tensile bearing capacity and degradation intensity of reinforcement traction under a constant pullout speed are investigated.. Additionally, to validate the results of physical modeling, the anchors with the best performance and the maximum tensile bearing capacity were selected as a representative of each group, modeled, and evaluated in PLAXIS 3D V.2018 finite element software program. Based on the results, the circular shaped mechanical anchor showed the maximum bearing capacity among the other anchors.

کلیدواژه‌ها [English]

  • Expandable Mechanical Plate Anchor (EMPLA)
  • Experimental modeling
  • Onshore and Offshore Geotechnics
  • Soil Reinforcement
  • PLAXIS (3D)
BLAKE A, O’LOUGHLIN C, “Installation of dynamically embedded plate anchors as assessed through field tests”, Canadian Geotechnical Journal, 2015, 52, 1270-1282.
BLAKE A, O’LOUGHLIN C, GAUDIN C, “Capacity of dynamically embedded plate anchors as assessed through field tests”, Canadian Geotechnical Journal, 2014, 52, 87-95.
CASSIDY M, GAUDIN C, Randolph M, Wong P, Wang D, Tian Y, “A plasticity model to assess the keying of plate anchors”, Géotechnique, 2012, 62, 825.
Copstead RL, Studier DD, “An earth anchor system: installation and design guide”, Gen. Tech. Rep. PNW-GTR-257. Portland, OR: US Department of Agriculture, Forest Service, Pacific Northwest Research Station, 1990, 35, 257.
DAS BM, Shukla SK, “Earth anchors”, Journal of Ross Publishing, 2013.
Gaudin C, O’loughlin C, Randolph M, Cassidy M, Wang D, Tian Y, Hambleton J, Merifield R, “Advances in offshore and onshore anchoring solutions”, Australian Geomechanics, 2014, 49, 59-72.
Gaudin C, O'loughlin C, Randolph M, Lowmass A, “Influence of the installation process on the performance of suction embedded plate anchors”, Géotechnique, 2006, 56, 381-391.
Gaudin C, Simkin M, White DJ, O’loughlin CD, “Experimental investigation into the influence of a keying flap on the keying behaviour of plate anchors”, The Twentieth International Offshore and Polar Engineering Conference, 2010. International Society of Offshore and Polar Engineers.
Gaudin C, Tian Y, Cassidy M, Randolph M, O’loughlin C, “Design and performance of suction embedded plate anchors”, Proceedings of 3rd International Symposium on Frontiers in Offshore Geotechnics. Oslo: CRC Press, 2015. 863-868.
Han C, Wang D, Gaudin C, O'loughlin C, Cassidy M, “Behaviour of vertically loaded plate anchors under sustained uplift”, Géotechnique, 2016, 66, 681-693.
Hoek E, Kaiser PK, Bawden WF, “Support of underground excavations in hard rock”, CRC Press, 2000.
Hung CJ, Monsees J, Munfah N, Wisniewski J, “Technical manual for design and construction of road tunnels-civil elements”, US Department of Transportation, Federal Highway Administration, National Highway Institute, New York, 2009.
Kulhawy FH, Trautmann CH, Nicolaides CN, “Spread foundations in uplift: experimental study”, Foundations for Transmission Line Towers, 1987. ASCE, 96-109.
Liu J, Liu M, Zhu Z, “Sand deformation around an uplift plate anchor”, Journal of Geotechnical and Geoenvironmental Engineering, 2011, 138, 728-737.
Moghadam MJ, Zad A, Mehrannia N, Dastaran N, “Experimental evaluation of mechanically stabilized earth walls with recycled crumb rubbers”, Journal of Rock Mechanics and Geotechnical Engineering, 2018a, 10, 947-957.
Moghadam MJ, Zad A, Mehrannia N, Dastaran N, “Experimental study of the influence of the shape and configuration of plate anchors on retaining walls”, International Journal of Physical Modelling in Geotechnics, 2018b, 1-49.
O’loughlin C, Blake A, Richardson M, Randolph M, Gaudin C, “Installation and capacity of dynamically embedded plate anchors as assessed through centrifuge tests”, Ocean Engineering, 2014, 88, 204-213.
O'loughlin C, Blake A, Gaudin C, “Towards a simple design procedure for dynamically embedded plate anchors”, Géotechnique, 2016, 66, 741-753.
O'loughlin C, White D, Stanier S, “Novel Anchoring Solutions for FLNG-Opportunities Driven by Scale”, Offshore Technology Conference, 2015, Offshore Technology Conference.
Randolph M, Gourvenec S, White D, Cassidy M, “Offshore geotechnical engineering”, Spon Press New York, 2011.
Shelton JT, “OMNI-Maxtrade anchor development and technology”, OCEANS 2007, 2007, IEEE, 1-10.
Song, Z, Hu Y, O’loughlin C, Randolph MF, “Loss in anchor embedment during plate anchor keying in clay”, Journal of Geotechnical and Geoenvironmental Engineering, 2009, 135, 1475-1485.
Tsuha CDHC, Aoki N, Rault G, Thorel L, Garnier J, “Evaluation of the efficiencies of helical anchor plates in sand by centrifuge model tests”, Canadian Geotechnical Journal, 2012, 49, 1102-1114.
Wang D, Merifield R, Gaudin C, “Uplift behaviour of helical anchors in clay”, Canadian Geotechnical Journal, 2013, 50, 575-584.
Wang D, O’loughlin C, “Numerical study of pull-out capacities of dynamically embedded plate anchors”, Canadian Geotechnical Journal, 2014, 51, 1263-1272.