Abstract




 
   

IJE TRANSACTIONS B: Applications Vol. 32, No. 5 (May 2019) 667-672   

PDF URL: http://www.ije.ir/Vol32/No5/B/7-3068.pdf  
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  EFFECT OF FUZZY BOUNDARIES ON THE BEARING CAPACITY OF FOOTINGS ON TWO-LAYERED CLAY
 
D. Azan and A. Haddad
 
( Received: November 10, 2018 – Accepted in Revised Form: May 02, 2019 )
 
 

Abstract    In this study, fuzzy logic was implemented to formulate the fuzziness of layer boundaries for a two-layered clay soil. A field of two-layered clay with fuzzy boundaries between layers was generated, and then the bearing capacity of strip footing on this field was calculated by the assumption of plane-strain conditions. The Mohr-Coulomb failure criterion was used and bearing capacity calculations were based on finite difference method. The effect of fuzziness in layer boundaries was investigated for the case of strong-over-weak clay. It is concluded that the analyses by applying fuzzy boundaries yielded more conservative results than classical two-layered bearing capacity calculations when the ratio of thickness of upper layer to the width of footing exceeds 1. When the ratio of thickness of upper layer to the width of footing is lower than 1, the bearing capacity of footing on two-layered clay is higher by considering fuzzy boundaries.

 

Keywords    Bearing Capacity; Difference Method; Fuzzy Boundary; Fuzzy Logic; Uncertainty; Two-layered Clay; Finite

 

چکیده   

در این تحقیق منطق فازی جهت فرموله کردن ابهام در مرز لایه بندی برای خاک رسی دو لایه استفاده شده است. میدان خاکی با لحاظ مرزبندی فازی میان لایه¬ها ایجاد شده و سپس ظرفیت باربری پی نواری واقع بر این میدان توسط فرضیه کرنش صفحه¬ای محاسبه شده است. جهت محاسبه ظرفیت باربری مدل مور-کلمب با بهره گیری از روش تفاضل محدود استفاده شده است. اثر ابهام در مرز لایه¬بندی برای خاک دولایه رسی لایه سخت بر لایه ضعیف¬تر مورد بررسی قرار گرفته است. نتایج نشان¬دهنده این مطلب است که با اعمال لایه¬بندی فازی کاهش در ظرفیت باربری هنگامی که عمق لایه اول از عرض پی بیشتر است رخ می¬دهد. در حالتی که عمق لایه¬ی اول کمتر از عرض پی است ظرفیت باربری خاک دو لایه رسی با لحاظ مرزبندی فازی افزایش می¬یابد.

References   

1.   Haddad, A. and Azan, D., "Soil cohesion spatial variability effects on the bearing capacity of nonhomogeneous clays", Modares Civil Engineering journal,  Vol. 18, No. 4, (2018), 1-13.
2. Azan, D. and Haddad, A., "Simple equations for considering spatial variability on the bearing capacity of clay", Civil Engineering Journal,  Vol. 5, No. 1, (2019), 93-106.
3. Li, J., Tian, Y. and Cassidy, M.J., "Failure mechanism and bearing capacity of footings buried at various depths in spatially random soil", Journal of Geotechnical and Geoenvironmental Engineering,  Vol. 141, No. 2, (2015), 04014099.
4. Javdanian, H., "Assessment of shear stiffness ratio of cohesionless soils using neural modeling", Modeling Earth Systems and Environment,  Vol. 3, No. 3, (2017), 1045-1053.
5. Javdanian, H., Jafarian, Y. and Haddad, A., "Predicting damping ratio of fine-grained soils using soft computing methodology", Arabian Journal of Geosciences,  Vol. 8, No. 6, (2015), 3959-3969.
6. Jafarian, Y., Haddad, A. and Javdanian, H., "Predictive model for normalized shear modulus of cohesive soils", Acta Geodynamica et Geomaterialia,  Vol. 11, No. 1, (2013), 89-100.
7. Javdanian, H., "The effect of geopolymerization on the unconfined compressive strength of stabilized fine-grained soils", International Journal of Engineering-Transactions B: Applications,  Vol. 30, No. 11, (2017), 1673-1680.
8. Jahanandish, M. And Azan, D., "Three-dimensional analysis of bearing capacity of square footings on convex slopes by finite element method", Iranian Journal of Science and Technology Transactions of Civil Engineering,  Vol. 39, No. C2+, (2015), 511-522.
9. Xiao, Y., Zhao, M. and Zhao, H., "Undrained stability of strip footing above voids in two-layered clays by finite element limit analysis", Computers and Geotechnics,  Vol. 97, (2018), 124-133.
10. Das, B.M., "Shallow foundations: Bearing capacity and settlement", Third Edition ed, Boca Raton, CRC Press,  (2017 ),  400 
11. Javdanian, H., Haddad, A. and Mehrzad, B., "Experimental and numerical investigation of the bearing capacity of adjacent footings on reinforced soil", Electronic Journal of Geotechnical Engineering,  Vol. 17, (2012), 2597-2617.
12. Ahmadi, M.M., Kouchaki, B.M. and Juhlin, C., “New and Simple Equations for Ultimate Bearing Capacity of Strip Footings on Two-Layered Clays: Numerical study”, International Journal of Geomechanics, Vol. 16, No. 4, (2016), 06015014.
13. Lotfizadeh, M.R., Kamalian M., “Estimating Bearing Capacity of Strip Footings over Two-Layered Sandy Soils Using the Characteristic Lines Method” International Journal of Civil Engineering, Vol. 14, No. 2, (2016), 107-116.
14. Rao, P., Liu, Y., Cui, J. “Bearing capacity of strip footings on two-layered clay under combined loading” Computers and Geotechnics, Vol. 69, No. 2, (2015), 210-218.
15. Benmebarek, S., Benmoussa, L., Belounar, L., Benmebarek, N., “Bearing Capacity of Shallow Foundation on Two Clay Layers by Numerical Approach”, Geotechnical and Geological Engineering, Vol. 30, No. 4, (2012), 907-923.
16. Bandini, P., Pham, H., “Bearing Capacity of Embedded Strip Footings in Two-Layered Clay Soils”, American Society of Civil Engineers, Vol. 16, No. 4, (2011), 332-341.
17. Abbaszadeh Shahri, A., Malehmir, A. and Juhlin, C., “Soil classification analysis based on piezocone penetration test data - A case study from a quick-clay landslide site in southwestern Sweden”, Engineering Geology, Vol. 189, (2015), 32-47.
18. Fathi A., Poursartip B., Stokoe I., Kallivokas L.F., “Three-dimensional P- and S-wave velocity profiling of geotechnical sites using full-waveform inversion driven by field data”, Soil Dynamics and Earthquake Engineering, Vol. 87, No. 4, (2016), 63-81.
19. Zhang Z., Tumay, M.T., Zhao, H. “Statistical to Fuzzy Approach Toward CPT Soil Classification” Journal of Geotechnical and Geoenvironmental Engineering, Vol. 125, No. 3, (1999), 179-186.
20. Zadeh, L.A. “Fuzzy sets Information and Control” Computers and Geotechnics, Vol. 8, No. 3, (1965), 338-353.
21. Wang L.X., Sumathi S., Deepa S. “A Course in Fuzzy Systems and Control”, Prentice Hall PTR, (1997).
22. Sivanandam S., Sumathi S., Deepa S. “Introduction to fuzzy logic using MATLAB vol 1”, Springer, (2007).
23. FLAC Itasca, “Fast lagrangian analysis of continua (FLAC), Version 5.0, Manual”, Itasca, Minnesota, Mineapolis, (2007). 


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