Derin Kazı Analizlerinde Küçük Şekil Değiştirme Rijitliğinin Etkisi

Abstract

Zemin-yapı etkileşiminde derin kazı destek sistemlerinin davranışı son yıllarda pek çok araştırmacı tarafından çalışılmaktadır. Ancak zeminin küçük şekil değiştirme rijitliğini dikkate alan çalışmalar çok fazla bulunmamaktadır. Bu durumun sebebi olarak bu etkiyi değerlendiren sonlu elemanlar programlarının yeterli sayıda bulunmayışı söylenebilir. Bu çalışma kapsamında geoteknik problemlerin çözümünde sıkça kullanılan bir sonlu elemanlar programı olan Plaxis yazılımı ile analizler gerçekleştirilmiştir. Programın kütüphanesinde birçok zemin modeli bulunmaktadır. Bunlar arasında sıkça kullanılan Pekleşen Zemin Modeli (Hardening Soil Model) ve bu modelin küçük şekil değiştirme rijitliği etkilerini dikkate alan Pekleşen Zemin Küçük Birim Deformasyon Modeli (Hardening Soil Small Strain Model) bu çalışmada kullanılmıştır. Bu modeller ile üç adet vakanın analizleri gerçekleştirilmiştir. Analiz sonuçları inklinometre ölçümleri ile karşılaştırılmıştır. Çalışma sonucunda model analiz sonuçları ile yerinde alınan ölçümler karşılaştırmalı olarak sunulmuştur. HS_ss modelin HS modele göre saha ölçümlerine daha yakın olduğu görülmüştür.

Keywords

• Derin Kazılar,Pekleşen Zemin Modeli,Pekleşen Zemin Küçük Birim Deformasyon Model

The Effect of Small Strain Stiffness in Deep Excavation Analyzes

Abstract

The behavior of deep excavation support systems at soil-structure interaction has been studied by many researchers in recent years. However, studies that considering the rigidity of the small strain of the soil are not very common. For this situation, it can be said that there is not enough number of finite element programs evaluating this effect. Within the scope of this study, analyzes were performed by Plaxis software, is a finite element program, is frequently used to solve geotechnical problems. There are many soil models in the library of the program. Among these, Hardening Soil Model (HS), which is frequently used, and Hardening Soil Small Strain Model (HS_ss), which takes into account the effects of small strain stiffness of this model, were used in this study. Three cases were analyzed with these models. The analysis results were compared with the inlinometer measurements. As a result of the study, model analysis results and in situ measurements are presented comparatively. The HS_ss model was found to be closer to the field measurements than the HS model.

Keywords

• Deep Excavation,Hardening Soil Model,Hardening Soil Small Strain Model

References

1. [1] Lim, A., Ou, C. Y., and Hsieh, P. G. (2010), "Evaluation of Clay Constitutive Models for Analysis of Deep Excavation under Undrained Conditions", Journal of GeoEngineering,TGS,Vol.5 (1), 9-20.
2. [2] Zhang, W., Goh, A. and Zhang Y. (2015), “Probabilistic Assessment of Serviceability Limit State of Diaphragm Walls for Braced Excavation in Clays”, ASCE-ASME J. Risk Uncertainty Eng. Syst., Part A: Civ. Eng., 2015, 1(3): 06015001-1.
3. [3] Hsiung B.B., Sakai, T. (2016), “Failure Analysis of Underground Construction—Lessons Learned from Taiwan”, Forensic Geotechnical Engineering, pp.197-208.
4. [4] Mu, L., Finno, R. J., Huang, M., Kim, T., & Kern, K. (2015), “Defining The Soil Parameters For Computing Deformations Caused By Braced Excavation”, Maejo International Journal of Science and Technology, 9(2), 165.
5. [5] Likitlersuang, S., Surarak, C., Wanatowski, D., Oh, E., & Balasubramaniam, A. (2013),“Finite Element Analysis of A Deep Excavation: A Case Study from the Bangkok MRT”, Soils and Foundations, 53(5), 756-773.
6. [6] Castaldo, P., & De Iuliis, M. (2014),“Optimal Integrated Seismic Design of Structural and Viscoelastic Bracing‐Damper Systems”, Earthquake Engineering & Structural Dynamics, 43(12), 1809-1827.
7. [7] Lim, A., & Ou, C. Y. (2017). “Stress paths in deep excavations under undrained conditions and its influence on deformation analysis.” Tunnelling and Underground Space Technology, 63: 118-132.
8. [8] Schanz, T., Vermeer, P., and Bonier, P. (1999), “Formulation and Verification of the Hardening Soil Model. In Beyond 2000 in Computational Geotechnics, Balkema, Rotterdam.

9. [9] Duncan, J. M. and Chang, C. Y. (1970), "Nonlinear Analysis of Stress And Strain in Soils", Journal of the Soil Mechanics and Foundations Division, ASCE, Vol. 96, pp. 1629-1653.
10. [10] Janbu, N. (1985), "Soil Models In Offshore Engineering", Géotechnique 35(3) 241-281.
11. [11] Kempfert, H. G., & Gebreselassie, B. (2006), “Constitutive Soil Models and Soil Parameters”, Excavations and Foundations in Soft Soils, 57-116.
12. [12] Jaky, J. (1944). The coefficient of earth pressure at rest. Journal of the Society of Hungarian Architects and Engineers, 78(22), 355-358.
13. [13] Brinkgreve, R.B.J. (2002), “PLAXIS Finite Element Code for Soil and Rock Analysis-Version 8”. Balkema, Rotterdam.
14. [14] Benz, T. (2007), “Small-Strain Stiffness of Soils and Its Numerical Consequences”, Phd Thesis, Universitat Sttutgart.
15. [15] Hardin, B. O., & Drnevich, V. P. (1972), “Shear Modulus and Damping in Soils: Design Equations and Curves”, Journal of Soil Mechanics & Foundations Div, 98(sm7).
16. [16] Zimmermann, T., Truty, A., Podles, K. (2010) “Numerics In Geotechnics And Structures”, Elmepress international, Lausanne.
17. [17] Yamashita, S., Kawaguchi, T., Nakata, Y., Mikami, T., Fujiwara, T., & Shibuya, S. (2009), “Interpretation Of International Parallel Test On The Measurement of Gmax Using Bender Elements. Soils and Foundations”, 49(4), 631-650.
18. [18] Dong, Y., Ning L., F.(2016). “Correlation between Small-Strain Shear Modulus and Suction Stress in Capillary Regime under Zero Total Stress Conditions” J. Geotech. Geoenviron. Eng., 10.1061/(ASCE)GT.1943-5606.0001531.
19. [19] Vardanega, P.J., Bolton, M.D.(2013).”Stiffness of Clays and Silts: Normalizing Shear Modulus and Shear Strain”, J. Geotech. Geoenviron. Eng., 10.1061/(ASCE)GT.1943-5606.0000887.
20. [20] Clough, G.W. ve O’Rourke, T.D. “Wall Deflection and Ground Surface Settlement Induced by Excavation”, In Proceedings of the 4th National Geotechnical Conference, 1990, Hawlin, Taiwan.