EFFECTIVE STRESS BASED NUMERICAL ANALYSIS OF LATERAL DEFORMATIONS DUE TO CYCLIC MOBILITY

Öz

Cyclic mobility is a dynamic soil behaviour observed in saturated cohesionless soils under dynamic loads in which large amounts of shear deformation is accumulated after initial liquefaction and gives way to great lateral displacements. In this paper, one dimensional site response analyses are carried out on medium and verd dense sand profiles under sinuzoidal lateral acceleration in order to investigate numerically the development of cyclic mobility. The analyses are performed by using the nonlinear finite element method in OPENSEES framework and the cyclic mobility behaviour is represented by an effective stress based model called PDMY (Pressure Dependent Multi-Yield Surface Plasticity ) model. The results of the study showed that the development of cyclic mobility behaviour is strongly dependent on the relative density and initial effective stress conditions of the sand stratum, driving shear stresses, residual strength and the duration, frequency and the amplitude of the dynamic load

Anahtar Kelimeler

• Liquefaction, Flow liquefaction, Cyclic mobility

ÇEVRİMSEL HAREKETLİLİK DAVRANIŞINA BAĞLI YANAL ZEMİN DEFORMASYONLARININ EFEKTİF GERİLME TABANLI SAYISAL ANALİZİ

Öz

Çevrimsel hareketlilik, dinamik yükler altındaki suya doygun kum zeminlerde, sıvılaşma meydana geldikten sonra kayma deformasyonlarının birikmesi sonucunda yüksek düzeylerde yanal yerdeğiştirmelerin oluşmasına neden olan dinamik bir zemin davranışıdır. Bu çalışmada, çevrimsel hareketlilik davranışının oluşum sürecini sayısal olarak ortaya koymak amacı ile orta sıkı ve çok sıkı suya doygun kum tabakalarına uygulanan sinüzoidal yanal yer ivmesi altında bir boyutlu zemin tepkisi analizleri gerçekleştirilmiştir. Yapılan parametrik çalışmalarda sayısal analiz yöntemi olarak doğrusal olmayan sonlu elemanlar yöntemi, çevrimsel hareketlilik davranışının temsil edilebilmesi için ise efektif gerilme tabanlı bir zemin modeli olan PDMY (Pressure Dependent Multi-Yield Surface) plastisite modeli kullanılmıştır. Analizler OPENSEES sonlu eleman açık kod ortamında gerçekleştirilmiştir. Analizler sonucunda kum zeminin sıkılığı, başlangıç efektif gerilme durumu, dinamik yükleme öncesinde maruz kaldığı statik kayma gerilmeleri, rezidüel kayma dayanımı ile dinamik yüklemenin süresi, frekansı ve genliğinin çevrimsel hareketlilik davranışı üzerinde büyük ölçüde etkili oldukları görülmüştür.

Anahtar Kelimeler

• Sıvılaşma, Akma sıvılaşması, Çevrimsel hareketlilik

Kaynakça

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