Numune Örselenmesinin Geleneksel Ödometre Deneyleri ile Belirlenen Konsolidasyon Parametrelerine Olan Etkilerinin İncelenmesi

Yıl 2022, Cilt: 4 Sayı: 2, 278 - 286, 26.10.2022

Muharrem Dumanlılar , Mustafa Fener , Mehmet Can Balcı

https://doi.org/10.46387/bjesr.1168588

Öz

Bu çalışmada, numune örselenmesinin geleneksel konsolidasyon deneyleriyle elde edilen sıkışma eğrileri ve ön konsolidasyon gerilmesine (sp') olan etkileri incelenmiştir. Laboratuvara getirilen numuneler sistematik olarak %10, %20, %30, %40 ve %50 oranında içleri boşaltılıp geri doldurularak örselenmiştir. Örselenme oranının artmasıyla, sıkışma eğrisi üzerinde sp' değerlerinin belirlenmesinin giderek zorlaştığı, sıkışma eğrisindeki tipik büküm noktasının giderek belirginsin bir hale geldiği ve %40 örselenme oranına kadar örselenen zemin numunelerinin sp' değerlerinde önemsenmeyecek miktarda değişimlerin olduğu tespit edilmiştir. Ön konsolidasyon gerilmesi gibi konsolidasyon parametrelerinin belirlenemediği zemin numunelerinin %40'dan daha fazla örselenmeye maruz kaldığı ve bu tür örnekler üzerinde konsolidasyon parametrelerinin belirlenmemesi gerektiği önerilmektedir.

Anahtar Kelimeler

Sistematik Numune Örselenmesi, Ön Konsolidasyon Gerilmesi, Odometre Deneyi, Konsolidasyon Parametreleri

Investigation of the Sample Disturbance Effects on Consolidation Parameters Obtained from Conventional Oedometer Tests

Öz

This study explores the effects of sample disturbance on the compression curves obtained from oedometer tests and the inferred effective preconsolidation stress (sp'). The samples were systematically disturbed by removing different fractions of the soil ranging from 10%, 20%, 30%, 40%, and 50% and remolding them back into place to reach the same initial void ratio. It was found that when the rate of disturbance was increased, it became more difficult to determine the sp' values on the compression curve; the typical bending point on the compression curve became increasingly indistinct, and negligible changes occurred in the sp' values of the disturbed soil samples up to a disturbance rate of 40%. If the soil samples whose consolidation parameters such as preconsolidation stress can’t be determined are subjected to disturbances greater than 40%, it is recommended that no consolidation parameter of such samples be specified.

Anahtar Kelimeler

Systematic Sample Disturbance, Preconsolidation Stress, Oedometer Test, Consolidation Parameters.

Kaynakça

• [1] J. Feda “Stress in Subsoil and Methods of Final Settlement Calculation”, Developments in Geotechnical Engineering, vol. 18, pp. 216, 1978.
• [2] A. Casagrande “The Structure of Clay and Its Importance in Foundation Engineering”, Boston Society Civil Engineers Journal, 1932.
• [3] A. Casagrande, “The determination of pre-consolidation load and it's practical significance”, Proceedings of the International Conference on Soil Mechanics and Foundation Engineering, Cambridge, Massachusetts, vol. 3, pp. 60, 1936.
• [4] J.H. Schmertmann “The Undistrubed Consolidation Behaviour of Clay”, Transactions of the American Society of Civil Engineers, 120(1), 1201-1227, 1955.
• [5] F. Pacheco Silva “A new graphical construction for determination of the preconsolidation stress of a soil sample” Proceedings of the 4th Brazilian Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, Brazil, vol. 2, no. 1, pp. 225-232, 1970.
• [6] R.E. Smith, H.E. Wahls “Consolidation Under Constant Rates of Strain”, Journal of the Soil Mechanics and Foundations Division, vol. 95, no. 2, pp. 519-539, 1969.
• [7] J. Lowe III, E. Jonas, V. Obrican “Controlled Gradient Consolidation Test”, Journal of Soil Mechanics and Foundations Divisions, vol. 95, no. 1, pp. 77-97, 1969.
• [8] F. Tavenas, S. Leroueil “Effects of stresses and time on yielding of clays”, Ninth International Conferance on Soil Mechanics and Foundation Engineering, Tokyo, pp. 319-326. 1977.
• [9] S. Leroueil, J.P. LeBihan, F. Tavenas “An Approach for the Determination of the Preconsolidation Pressure in Sensitive Clays”, Canadian Geotechnical Journal, vol. 17, no. 3, pp. 446-453, 1980.
• [10] W.H. Ward, S.G. Samuels, M.E. Butler “Further Studies of the Properties of London Clay”, Geotechnique, vol. 9, no. 2, pp. 33-58, 1959.
• [11] H. Cetin “How did the Meers Fault Scarp Form? Paleoearthquake or Aseismic Creep? A Soil Mechanical Perspective”, Eng Geol, vol. 47, pp. 289-310, 1997a.
• [12] H. Cetin “An Experimental Study of Soil Memory and Preconsolidation Adjacent to An Active Tectonic Structure: The Meers Fault, Oklahoma, USA”, Eng Geol, vol. 57, no. 3-4, pp. 169-178, 2000.
• [13] O. Gunaydin, H. , Cetin “Determination of Stress Distribution on Active Fault by Means of Casagrande Method; An Innovative Approach”, Soil Dynamics and Earthquake Engineering, vol. 129, p. 105920, 2020.
• [14] S. Yang, K.H. Andersen, T. Lunne, G. Yetginer “Effect of Sample Disturbance on Cyclic Shear Strength of Normally to Lightly OC Clays”, International Journal of Geotechnical Engineering, vol. 14, no. 3, pp. 242-253, 2020.
• [15] G.T. Lim, J. Pineda, N. Boukpeti, J.A.H. Carraro, A. Fourie “Effects of Sampling Disturbance in Geotechnical Design”, Canadian Geotechnical Journal, vol. 56, no. 2, pp. 275-289, 2019.
• [16] P. Tommasi, A. Avalle, F. Budillon, R. Romeo, A. Caburlotto, A. Conforti, G. Di Martino, A. Pagliaroli, M. Magagnoli, R. Urgeles, J. Llopart “Evaluation of Disturbance Induced on Soft Offshore Sediments by Two Types of Gravity Piston Coring Techniques”, Marine Geology, vol. 417, pp. 106005, 2019.
• [17] W.G. Lukas, D.J. DeGroot, J.T. DeJong, C.P. Krage, G. Zhang “Undrained Shear Behavior of Low-Plasticity Intermediate Soils Subjected to Simulated Tube-Sampling Disturbance”, Journal of Geotechnical and Geoenvironmental Engineering, vol. 145, no. 1, pp. 04018098, 2019.
• [18] M. D’Ignazio, H.P. Jostad, T. Länsivaara, V. Lehtonen, J. Mansikkamäki, C. Meehan “Effects of sample disturbance in the determination of soil parameters for advanced finite element modelling of sensitive clays” Landslides in Sensitive Clays., Springer, 45-154, 2017.
• [19] R. Carroll, M. Long “Sample Disturbance Effects in Silt”, Journal of Geotechnical and Geoenvironmental Engineering, vol. 143, no. 9, 2017.
• [20] M. Karlsson, A. Emdal, J. Dijkstra “Consequences of Sample Disturbance When Predicting Long-Term Settlements in Soft Clay”, Canadian Geotechnical Journal vol. 53, no. 12, pp. 1965-1977, 2016.
• [21] D.G. Zapata-Medina, R.J. Finno, C.A Vega-Posada “Stress History and Sampling Disturbance Effects on Monotonic and Cyclic Responses of Overconsolidated Bootlegger Cove clays”, Canadian Geotechnical Journal, vol. 51, no. 6, pp. 599-609, 2014.
• [22] V. Horng, H. Tanaka, H. Hirabayashi, R. Tomita “Sample Disturbance Effects on Undrained Shear Strengths -Study From Takuhoku Site, Saparro”, Soils and Foundations, vol. 51, no. 2, pp. 203-213, 2011.
• [23] O.G. Ingles, D. Lafeber “The Influence of Volume Defects on the Strength and Strength Isotropy of Stabilized Clays”, Engineering Geology, vol. 1, no. 4, pp. 305-310, 1966.
• [24] T. Lunne, T. Berre, S. Strandvik “Sample disturbance effects in deep water soil investigations”, Offshore Site Investigation and Foundation Behaviour New Frontiers: Proceedings of an International Conference Society of Underwater Technology January, pp. 98-199, 1998.
• [25] T. Lunne, T. Berre, K.H. Andersen, S. Strandvik, M. Sjursen “Effects of Sample Disturbance and Consolidation Procedures on Measured Shear Strength of Soft Marine Norwegian Clays”, Canadian Geotechnical Journal, vol. 43, no. 7, pp. 726-750, 2006.
• [26] T. Lunne, T. Berre, K.H. Andersen, M. Sjursen, N. Mortensen, A.B. Huang, P.W. Mayne “Effects of sample disturbance on consolidation behaviour of soft marine Norwegian clays”, International Conference on Site Characterization 3, pp. 1471-1479, 2008.
• [27] American Society for Testing Materials. 2003. Standard Test Method for One-Dimensional Consolidation Properties of Soils, ASTM Standard D2435, West Conshohocken, PA.
• [28] R.M. Quigley, C.D. Thompson “The Fabric of Anisotropically Consolidated Sensitive Marine Clay”, Canadian Geotechnical Journal, vol. III, no.2, pp. 61-63. 1966.
• [29] R.D. Holtz, W.D. Kovacs, and T.C. Sheahan “An introduction to geotechnical engineering”, vol. 733, Englewood Cliffs: Prentice-Hall., 1981.