KUM / GEOTEKSTGL ARAYÜZEY KAYMA DAYANIMININ KESME KUTUSU DENEYLERGȱGLE BELGRLENMESG

Öz

Geoteknik mühendisliği alanında geosentetik malzemelerin kullanımına günümüzde oldukça yaygın bir şekilde rastlanmaktadır. Geoteknik uygulamalarda geosentetikler ayırma, filtrasyon, drenaj, güçlendirme işlevlerinden biri esas olmak üzere birçok işlevi bir arada yerine getirirler. Yüksek çekme dayanımına sahip bir geosentetik malzeme olan geotekstiller zeminin kayma mukavemetinde iyileşmeye neden olarak zemini güçlendirme görevini görürler, bu nedenle geotekstillerle güçlendirilmiş zeminler donatılı zemin olarak da adlandırılırlar. Özellikle yol inşaatlarında stabiliteyi artırmada ve temel altı tabakasını güçlendirmede kullanılan geosentetik malzemelerinin zeminin mekanik özelliklerini ne ölçüde iyileştirdiği birçok çalışmanın konusu olmuştur. Bu çalışma kapsamında, kumlu zeminlerde geotekstil kullanımının statik yükleme koşulları altında zeminin stabilitesindeki artış miktarına etkisi incelenmiştir. Bu amaçla bir seri kesme kutusu deneyi yapılmıştır. Deneysel çalışmalarda farklı tip ve özelliklerdeki geotekstiller kullanılarak kumların kayma direnci özelliklerinin ne ölçüde değiştiği araştırılmıştır.Deney sonuçları, geotekstil tipi, kum zeminin granülometrisi ve relatif sıkılığı ile deneysel koşullardaki farklılıkların ara yüzey kayma dayanımı parametreleri üzerinde büyük ölçüde etkili olduğunu ortaya koymuştur.

Anahtar Kelimeler

• Kum, geotekstil, kesme kutusu deneyi, ara yüzey sürtünme açısı, ara yüzey etkileşim katsayısı

Determination of Sand / Geotextile Interface Shear Strength by Direct Shear Tests

Abstract

Recently, in geotechnical engineering field, applications of geosynthetics are gettingrather more common. Geosynthetics are capable of overcoming a number of problems includingseperation, filtration, drainage, reinforcement; which multiple functions can be fulfilled once at atime. Particularly, application of a type of geosynthetics, namely, geotextiles, which are possessingrather high tensile strength, lead to increase in the shear strength of soil, hence, soils strengthenedwith geosythetics are named as reinforced soil.In particular, many studies in the literature are related with the investigation of the rate ofincrease in soil strength by application of geosynthetic materials, which are used for increasing thestability and reinforcing the subgrade material in highway construction. In the scope of this study,the effect of geotextile type on the rate of increase in stability of sandy soils, is investigated understatic loading conditions. Shear box tests on specimens prepared by inclusion of geotextiles ofdifferent types and properties, were carried out to assess the rate of variation in sand shear strengthproperties. It was observed that geotextile type, grain size distribution, relative density of sand andthe test parameters cause drastic variations in the sand / geotextile interface shear strength behaviour.

Keywords

• Sand, geotextiles, direct shear test, interface friction angle, interface coefficient of friction

Kaynakça

1. ASTM D-698 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12400 ft-lbf/ft3-600kN-m/m3)), ASTM International, West Conshohocken, PA, USA.
2. ASTM D-4253-00 (2006) Standard Test Methods for Maksimum Indeks Density and Unit Weight of Soils Using a Vibratory Table, ASTM International, West Conshohocken, PA, USA.
3. ASTM D-4254-00 (2006) Standard Test Methods for Minimum Indeks Density and Unit Weight of Soils and Calculation of Relative Density, ASTM International, West Conshohocken, PA, USA.
4. ASTM 5321-08 Standard Test Method for Determining the Coefficient of Soil and Geosynthetic or Geosynthetic and Geosynthetic Fricton by the Direct Shear Method, ASTM International, West Conshohocken, PA, USA.
5. Cazzufi,D.,Picarelli,L., Ricciuti,A.,Rimoldi,P., (1993), Laboratory Investigations on the Shear Strength of Geogrid Reinforced Soils, Geosynthetic Soil Reinforcement Testing Procedures, ASTM STP 1190, S.C. Jonathan Cheng Ed., American Society for Testing and Materials, Philadelphia.
6. Cowell, M.J., and Sprague, C.J. (1993). “Comparison of Pull-out Performance of Geogrids and Geotextiles.”, Geosynthetics ’93, 579-592.
7. Daniele, C., Picarelli L., Ricciuti A., Rimold P. (1993), “Laboratory investigations on the shear strength of geogrid reinforced soils”, ASTM Special Technical Publication Symposium on Geosynthetic Soil Reinforcement Testing Procedures, No. 1190, 119-137.
8. Haeri, S.M, Noorzad, R.; Oskoorouchi, A.M. (2000), “Effect of geotextile reinforcement on the mechanical behavior of sand”, Geotextiles and Geomembranes, Vol. 18, No.6, 385-402.

9. Imauzumi S., Nishigata, T., Limura, K. (1994), “Effect of Variation in Sample Sizes on Soil-Polymer Interface Strength”, Proceedings of the Fifth International Conference on Geotextiles, Geomembranes and Related Products, SEAC-IGS, Singapore, pp:423-426.
10. Ingold, T. S., (1982) "Some Observations on the Laboratory Measurement of Soil-Geotextile Bond," Geotechnical Testing Journal, Vol. 5, No. 3/49, 57-67.
11. Ingold, T. S., (1991) “Friction Testing In: Geomembranes Identification and Performance Testing”, A.Rollin and J.M.Rigo ed., Chapmen and Hall, pp.176-203.
12. Koutsourais, M.M., Sprague, C.J., Precutas, R.C. (1991), Interfacial Friction Study of Cap And Liner Components For Landfill Design, Journal of Geotextiles and Geomembranes, Vol.10, No. 5/6, 531-548.
13. Lee, K.M., Manjunath, V.R (2000), “Soil-geotextile interface friction by direct shear tests”, Canadian Geotechnical Journal, Vol. 37, No.1, 238-252.
14. Long, P.V, Bergado, D.T, Balasubramaniam A.S, Delmas P. (1997), “Interaction between soil and geotextile reinforcement”, Geotechnical Special Publication, No.69, Ground Improvement, Ground Reinforcement, Ground Treatment, 60-578, Proceedings of the 1997 1st National Conference of the ASCE Geo-Institute, Geo-Logan, July 16-18 1997, Logan, UT, USA.
15. Rajagopal, K., Krishnaswamy N.R., Latha, G.M. (1999), “Behaviour of sand confined with single and multiple geocells”, Geotextiles and Geomembranes, Vol. 17, No. 3, 171-184.
16. Tan, S.A., Chew, S.H., Wong, W.K. (1998), “Sand-geotextile interface shear strength by torsional ring shear tests”, Geotextiles and Geomembranes, Vol.16, No.3, 161-174.
17. TatlÍsöz, N., Edil, T.B., Benson, CH. (1998), “Interaction Between reinforcing geosynthetics and soiltire chip mixtures”, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 124, No.11, 1109-1119.
18. Taylor, D.W.1948. Fundamentals of Soil Mechanics, Wiley, New York.
19. Yetimoglu, T, Salbas, O. (2003), “A study on shear strength of sands reinforced with randomly distributed discrete fibers”, Geotextiles and Geomembranes, Vol. 21,No.2, 103-110.
20. Zhang, M.X, Javadi, A.A; Min, X. (2006), Triaxial tests of sand reinforced with 3D inclusions, Geotextiles and Geomembranes, 24, 4, 201-209.