EPS Ara Dolgu Kullanýmýnýn Ankastre Ýstinat Duvarlarýnýn Statik Davranýþý Üzerindeki Etkileri

Bu çalýþmada, genleþtirilmiþ polistren (EPS) ara dolgu kullanýmýnýn, farklý duvar esnekliklerine sahip olan ankastre istinat duvarlarýnda oluþan yanal basýnç ve duvar sehimleri üzerindeki etkileri araþtýrýlmaktadýr. Bu amaç doðrultusunda, 0.7 m yüksekliðinde ve çeþitli kalýnlýklarda istinat duvarý modelleri hazýrlanarak laboratuvar ortamýnda deneyler yapýlmýþtýr. Birinci grup testlerde, duvar ile kohezyonsuz dolgu arasýnda herhangi bir ara dolgu yer almamasý durumu incelenmiþ, ikinci ve üçüncü test gruplarýnda ise duvar ile dolgu arasýnda iki farklý kalýnlýkta EPS’den imal edilen ara dolgu bulunmasý durumu incelenmiþtir. Dört farklý kalýnlýkta duvar için deneyler tekrarlanarak elde edilen bulgular karþýlaþtýrmalý olarak deðerlendirilmiþtir. Duvar esnekliði arttýkça ara dolgunun saðladýðý yük azaltýcý etki azalmaktadýr. Buna raðmen, esnek duvarlarda deforme olabilen ara dolgu kullanýmý, yanal zemin itkisi ve duvar sehimlerinde önemli oranlarda düþüþ saðlayarak daha ekonomik duvar tasarýmlarýna imkân verebilir. Model deneyler neticesinde elde edilen yanal zemin basýncý katsayýlarý, Coulomb yöntemi ile elde edilen aktif yanal basýnç katsayýlarýyla karþýlaþtýrýlmaktadýr. Duvar esnekliði ve ara dolgu özelliklerinin çeþitli kombinasyonlarý için, statik yanal basýnç katsayýlarýnýn tahmini amacýyla bir grafik sunulmaktadýr.

Influence of EPS Geofoam Buffers on the Static Behavior of Cantilever Earth-Retaining Walls

In this study, the effect of expanded polystyrene (EPS) buffers on lateral stresses and deflections of model retaining walls with various flexibility values were investigated. For this purpose, 0.7 m high model walls were instrumented and 1-g model tests were performed in laboratory environment. In the first group of tests, the wall models retain only granular cohesionless backfill whereas in the second and third group of tests, EPS deformable buffers of two different thicknesses were installed between the wall and granular backfill. Tests were repeated for four different wall thicknesses and results were discussed comparatively. As wall flexibility increases, there is a decrease in the load reduction pattern of the buffer. On the other hand, utilization of geofoam buffers with flexible cantilever walls still provides substantial decrease in wall thrust and deflections thus leading to more economical retaining structure design. The lateral earth pressure coefficients determined through model tests were compared to those calculated from Coulomb’s theory for active lateral earth stresses. A graph is provided for the estimation of lateral earth pressure coefficients for various combinations of wall flexibilities and buffer characteristics.