Uçucu Kül Bazlı Malzemelerle Güçlendirilen Killi Şevlerin Sayısal Analizi

Öz

Bu çalışma, kilden oluşan şev dolgularının stabilitesini artırmak amacıyla, C sınıfı uçucu kül, F sınıfı uçucu kül ve alkali aktivatör ile aktive edilmiş F sınıfı uçucu kül kullanım potansiyelini, PLAXIS yazılımı ile gerçekleştirilen 3 boyutlu sayısal modelleme aracılığıyla incelemektedir. Sayısal analizlerde kullanılan geoteknik parametreler, yazar tarafından daha önce yürütülen laboratuvar deneylerinden elde edilmiştir. Elde edilen sonuçlar, alkali aktivatörle stabilize edilmiş F sınıfı uçucu külün, güvenlik katsayısında belirgin artışlar ve plastik şekil değiştirme bölgelerinde azalmalar sağlayarak en etkili iyileştirmeyi sağladığını ortaya koymaktadır. C sınıfı uçucu kül, zemin rijitliğini belirli ölçüde artırsa da deformasyonu azaltma konusunda tam anlamıyla etkili olamamıştır. F sınıfı uçucu kül ise düşük reaktivitesi nedeniyle kontrol numunesine benzer bir davranış sergilemiş; ancak alkali aktivasyon sonrası performansında önemli iyileşmeler gözlenmiştir. Bu bulgular, özellikle granüler dolgu malzemesinin kısıtlı olduğu bölgelerde, yerel kil zeminlerin alkali aktivatör ile işlenmiş uçucu kül kullanılarak etkin şekilde iyileştirilebileceğini göstermektedir. Bu yaklaşım, yalnızca şev performansını artırmakla kalmayıp, aynı zamanda doğal kaynak tüketimini azaltarak ve inşaat maliyetlerini düşürerek daha sürdürülebilir geoteknik uygulamalara katkı sağlamaktadır.

Anahtar Kelimeler

• Şev Stabilitesi
• Plaxis 3D
• Uçucu Kül ile Zemin Iyileştirmesi
• Alkali Aktivasyon
• Kil

Numerical Investigation of Clayey Slopes Stabilised with Fly Ash-Based Materials

Öz

This study investigates the potential use of Class C fly ash, Class F fly ash, and alkali-activated Class F fly ash to improve the slope stability of clay embankments through 3D numerical modelling with PLAXIS. Laboratory-based input parameters, derived from previous experimental work by the author, were used to define the geotechnical behaviour of the soils in the simulations. Results demonstrate that clay slopes stabilised with alkali-activated Class F fly ash provides the most effective improvement, with significant increases in factor of safety and reductions in plastic strain zones. Although Class C fly ash moderately improved soil stiffness, it was not fully effective in mitigating deformation. Class F fly ash exhibited similar behaviour to the control sample due to its limited reactivity; however, its performance improved significantly following alkali activation. These findings suggest that, especially in regions where granular fill material is scarce, the slope stability of locally found clay soils can be effectively improved using alkali-activated fly ash. This approach not only enhances slope performance but also contributes to more sustainable geotechnical practices by reducing the consumption of natural resources and lowering overall construction costs.

Anahtar Kelimeler

• Slope Stability
• Plaxis 3D
• Fly Ash Stabilisation
• Alkali Activation
• Clay

Kaynakça

1. Farooq MU, Mujtaba H, Farooq K, Sivakugan N, Das BM. Evaluation of stability and erosion characteristics of soil embankment slope reinforced with different natural additives. Iranian Journal of Science and Technology, Transactions of Civil Engineering 2020;44:515-S524. doi:10.1007/s40996-019-00340-5.
2. Ikeagwuani CC, Nwonu DC. Stability analysis and prediction of coconut shell ash modified expansive soil as road embankment material. Transportation Infrastructure Geotechnology 2023;10:329-358. doi:10.1007/s40515-021-00215-1.
3. Skempton AW. Slope stability of cuttings in brown London clay. Selected papers on soil mechanics. London: Emerald Publishing; 1984.
4. Munoz YO, Almeida JL, Mora AJEV, Pudell PCA, Baldovino JA, Izzo RLS. The Behavior of Stabilized Reinforced Soil for Road Embankments Application. Geotechnical and Geological Engineering 2023;41:2599-2628. doi:10.1007/s10706-023-02416-6.
5. Praneeth S, Saavedra L, Zeng M, Dubey BK, Sarmah AK. Biochar admixtured lightweight, porous and tougher cement mortars: Mechanical, durability and micro computed tomography analysis. Science of the Total Environment 2021;750:142327. doi:10.1016/j.scitotenv.2020.142327.
6. Fraccica A, Spagnoli G, Romero E, Arroyo M, Gomez R. Exploring the mechanical response of low-carbon soil improvement mixtures. Canadian Geotechnical Journal 2021;59:5. doi:10.1139/cgj-2021-0087.
7. Turan C, Javadi A, Vinai R, Cuisinier O, Russo G, Consoli NC. Mechanical properties of calcareous fly ash stabilised soil. In: Proceedings of EUROCOALASH 2019. Dundee, UK; 2019.
8. Sharma N, Swain S, Sahoo U. Stabilization of a Clayey Soil with Fly Ash and Lime: A Micro Level Investigation. Geotechnical and Geological Engineering 2012;30(5):1197-1205. doi:10.1007/s10706-012-9532-3.

9. ASTM C618-05. Standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete. ASTM International; 2005.
10. Turan C, Javadi AA, Vinai R. Effects of Class C and Class F Fly Ash on Mechanical and Microstructural Behavior of Clay Soil—A Comparative Study. Materials 2022;15:1845. doi:10.3390/ma15051845.
11. Turan C, Javadi AA, Vinai R, Russo G. Effects of Fly Ash Inclusion and Alkali Activation on Physical, Mechanical, and Chemical Properties of Clay. Materials 2022;15:4628. doi:10.3390/ma15134628.
12. Corrêa-Silva M, Araujo N, Cristelo N, Miranda T, Gomes AT, Coelho J. Improvement of a clayey soil with alkali activated low-calcium fly ash for transport infrastructures applications. Road Materials and Pavement Design 2018;20:1912-1926. doi:10.1080/14680629.2018.1473286.
13. Dungca JR, Codilla EET. Fly-ash-based geopolymer as stabilizer for silty sand embankment materials. International Journal of Geomate 2018;14:143-149. doi:10.21660/2018.46.7181.
14. Leong HY, Ong DEL, Sanjayan JG, Nazari A. Strength Development of Soil–Fly Ash Geopolymer: Assessment of Soil, Fly Ash, Alkali Activators, and Water. Journal of Materials in Civil Engineering 2018;30:04018171. doi:10.1061/(ASCE)MT.1943-5533.0002363.
15. Sezer A, Inan G, Yilmaz HR, Ramyar K. Utilization of a very high lime fly ash for improvement of Izmir clay. Building and Environment 2006;41:150-155. doi:10.1016/j.buildenv.2004.12.009.
16. Phanikumar BR, Sharma RS. Volume Change Behavior of Fly Ash-Stabilized Clays. Journal of Materials in Civil Engineering 2007;19:67-74. doi:10.1061/(ASCE)0899-1561(2007)19:1(67).
17. Phanikumar BR. Effect of lime and fly ash on swell, consolidation and shear strength characteristics of expansive clays: A comparative study. Geomechanics and Geoengineering 2009;4:175-181. doi:10.1080/17486020902856983.
18. Kolay PK, Ramesh KC. Reduction of Expansive Index, Swelling and Compression Behavior of Kaolinite and Bentonite Clay with Sand and Class C Fly Ash. Geotechnical and Geological Engineering 2016;34:87-101. doi:10.1007/s10706-015-9930-4.
19. Seyrek E. Engineering behaviour of clay soils stabilized with class C and class F fly ashes. Science and Engineering of Composite Materials 2016;25:273-287. doi:10.1515/secm-2016-0084.
20. Zhou S, Zhou D, Zhang Y, Wang W. Study on Physical-Mechanical Properties and Microstructure of Expansive Soil Stabilized with Fly Ash and Lime. Advances in Civil Engineering 2019;2019:1-15. doi:10.1155/2019/4693757.
21. Zimar Z, Robert D, Sidiq A, Zhou A, Giustozzi F, Setunge S, Kodikara J. Waste-to-energy ash for treating highly expansive clays in road pavements. Journal of Cleaner Production 2022;374:133854. doi:10.1016/j.jclepro.2022.133854.
22. Sharma A, Shrivastava N. Slope Stability Assessment in Highway Embankments: A Comprehensive Study on Incorporating C&D Waste as Fill Material. Journal of Mining and Environment 2025;16(1):57-73. doi:10.22044/jme.2024.14510.2728.
23. British Standards Institution. BS 1377-2: Methods of test for soils for civil engineering purposes-Classification tests. BSI; 1990.
24. British Standards Institution. BS 1377-4: Methods of test for soils for civil engineering purposes-Compaction-related tests. BSI; 1990.
25. Turan C. Behaviour of clay stabilised with fly ash and alkali activated fly ash [PhD thesis]. Exeter: University of Exeter; 2023.
26. Ikeagwuani CC, Nwonu DC. Influence of Dilatancy Behavior on the Numerical Modeling and Prediction of Slope Stability of Stabilized Expansive Soil Slope. Arabian Journal for Science and Engineering 2021;46:11387-11413. doi:10.1007/s13369-021-05764-8.
27. Leroy MNL, Kenmoe ORM, Nkuissi HJT, Kouayep SL, Chebou GN, Chamgoue AC, Mohamadou I. Comparative Analysis of the Slope Stability Using Slide and Plaxis 2D Software: A Case Study of Tombel Pozzolan Quarry (South-West Cameroon). Applied and Environmental Soil Science 2024;2024:1-20. doi:10.1155/2024/8260177.
28. Shwan BJ. Numerical analysis of slopes treated by nano-materials. Journal of the Mechanical Behavior of Materials 2023;32:20220227. doi:10.1515/jmbm-2022-0227.
29. Rajak TK, Yadu L, Pal SK. Analysis of Slope Stability of Fly Ash Stabilized Soil Slope. Geotechnical Applications, Lecture Notes in Civil Engineering 2019;13:119-126. doi:10.1007/978-981-13-0368-5_13.
30. Hu B, Hu Q, Liu Y, Tao G. Research on the Improvement of Granite Residual Soil Caused by Fly Ash and Its Slope Stability under Rainfall Conditions. Applied Sciences 2024;14:3734. doi:10.3390/app14093734.