Normal Konsolide Kaolin Kilinin Drenajsız Kesme Davranışı Üzerinde Başlangıç Kayma Gerilmesinin Etkisi

Arazideki zeminlerin gerilme koşulları incelendiğinde, zeminlerin pek çok durumda anizotropik gerilme şartlarında olduğu görülmektedir. Bu zeminler, herhangi bir ilave yükleme olmasa dahi kayma gerilmesine maruz durumdadırlar. Günümüzde arazideki gerilme şartlarına bakılmaksızın, maliyet, zaman ve kolaylık gibi gerekçelerden dolayı üç eksenli basınç deneyleri izotropik gerilmeler altında ve başlangıç kayma gerilmesinin olmadığı numuneler üzerinde gerçekleştirilmektedir. Bu nedenle, zeminlerin drenajsız koşullardaki davranışı üzerinde başlangıç kayma gerilmesi varlığının etkisi belirlenmesi gereken önemli bir konudur. Bu çalışmada, laboratuvarda bulamaç çamuru konsolidasyon yöntemi ile hazırlanmış olan normal konsolide kaolin kilinin, farklı başlangıç kayma gerilmeleri ve ortalama efektif gerilmeler altındaki drenajsız davranışı üç eksenli basınç deneyleri kullanılarak incelenmiştir. Deney sonuçları, başlangıç kayma gerilmesindeki artışın, drenajsız kayma mukavemetini ve aşırı boşluk suyu basıncı oluşumunu önemli ölçüde etkileyebileceğini göstermektedir. Çalışma sonunda, izotropik koşullarda gerçekleştirilen üç eksenli basınç deneylerinden elde edilen drenajsız kayma mukavemeti kullanılarak, başlangıç kayma gerilmesine maruz kil zeminlerin drenajsız kayma mukavemetini belirlemeye yönelik olarak bir düzeltme faktörü önerilmiştir.

Effect of Initial Shear Stress on the Undrained Shear Behavior of Normally Consolidated Kaolin Clay

When the stress conditions of the soils in the field are examined, it is seen that the soils are in the anisotropic stress conditions in many cases. These soils are subjected to shear stress even without additional loading. Today, regardless of the stress conditions in the field, triaxial compression tests are carried out on samples without initial shear stress under the isotropic stress conditions because of the cost, time and simplicity. Therefore, determining the effect of the presence of the initial shear stress on the behavior of soils under the undrained conditions is an important subject. In this study, the undrained behavior of the normally consolidated kaolin clay, which is prepared by slurry consolidation method in the laboratory, under different initial shear stresses and mean effective stresses is investigated using the triaxial compression tests. The test results show that the increase in initial shear stress can significantly affect the undrained shear strength and the generation of excess pore water pressure. At the end of the study, a correction factor is proposed that can be used to determine the undrained shear strength of clay soils subjected to initial shear stresses by using the undrained shear strength obtained from the triaxial compression tests performed in isotropic conditions.

Keywords:

Initial Shear Stress, Pore Water Pressure, Undrained Shear Strength Correction Factor, Triaxial Compression Test.,

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