Donatılı Kum Zeminlerde Düzlem Deformasyon Koşullarında Düşey Gerilme Dağılışı

Year 2020, Volume: 31 Issue: 3, 9967 - 9985, 01.05.2020

Bayram Ateş , Erol Şadoğlu

https://doi.org/10.18400/tekderg.449897

Cited By: 4

Abstract

Teknolojinin gelişmesi insanoğluna daha geniş, daha ağır ve daha karmaşık yapılar yapma fırsatı vermiştir. Artan ve karmaşık hale gelen yükleri zemine aktarma problemi ile karşılaşan geoteknik mühendisleri için; zemini iyileştirmek, zeminde meydana gelecek oturmaları ve gerilme dağılışlarını tespit etmek kaçınılmaz hale gelmiştir. Son yıllarda zemini iyileştirmede kullanımı artan bir yapı malzemesi olan geotekstiller, zeminlerin taşıma gücünü etkilemektedir. Zeminde meydana gelecek oturmalar açısından gerilme dağılışı ve taşıma gücü temel tasarımının en önemli parametrelerden birkaçıdır. Bu çalışmada donatılı kum zemin yüzeyine oturan model şerit temelle düzlem deformasyon koşullarında deneyler yapılmış ve uygulanan düşey yükten dolayı zeminde belirli noktalarda meydana gelen düşey gerilme artışları tespit edilmiştir. Deneysel çalışma kapsamında, üç farklı rölatif sıkılıkta geotekstille güçlendirilmiş kum tabakalarında, önceden belirlenen noktalara yerleştirilen basınç ölçerler yardımıyla düşey gerilme artışları kaydedilmiştir. Daha sonra model deney düzeneği PLAXIS 2D programı ile modellenip Mohr-Coulomb modeli ile düşey gerilme artışları belirlenmiştir. Ayrıca donatılı zeminin, Elastisite Teorisine dayalı olarak geliştirilen analitik yöntemlerle (Poulos ve Boussinesq) düşey gerilme artışları hesaplanmıştır. Deneylerle elde edilen tüm değerler incelendiğinde, rölatif sıkılığın donatılı zemindeki gerilme dağılışında etkili bir parametre olduğu belirlenmiştir. Bununla birlikte, yaygın kullanılan Elastisite Teorisine dayalı çözümlerin düşük rölatif sıkılıktaki donatılı zeminlerde oldukça hatalı sonuçlar verdiği görülmüştür.

Keywords

Düşey gerilme artışı, basınç ölçer, donatılı zemin, geotekstil

Vertical Stress Distribution in Reinforced Sandy Soil in Plane Strain Conditions

Abstract

Development of technology gives the opportunity to mankind to build larger, heavier and more complex structures. For geotechnical engineers, faced with transferring the loads that is more complex and increasing, stabilization of soil, and determination of stress distribution and settlement has become inevitable. Geotextiles which have been used in soil stabilization increasingly in recent years affect bearing capacity of soil. Stress distribution in terms of settlement calculation and bearing capacity are some of the most important parameters for foundation design. In this study, several tests were carried out with model strip footing in plane strain conditions in reinforced cohesionless soil and the vertical stress increments occurred in the soil medium due to applied vertical surface loads were determined at several specific locations. In scope of experimental study, the sand reinforced with geotextile sheet was placed in layers in a tank with three different relative densities and vertical stress increments were measured by pressure gauges placed at predetermined locations. Subsequently, the experimental setup was modelled with PLAXIS 2D and vertical stress increments were obtained with Mohr-Coulomb model. Additionally vertical stress distribution in soil was calculated with analytical methods (Poulos and Boussinesq) based on elasticity theory. As the findings obtained from these studies were examined, it was understood that relative density is a very effective parameter for stress distribution in soils. However, the methods based on elasticity theory give rather erroneous results in low relative density reinforced soil.

Keywords

Vertical stress distribution, strain gauges, reinforced soil, geotextile

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