Hanifi CANAKCİ, Ali ALHASHEMY, Hamza GÜLLÜ

Development of Correlations for Compression Index

Sıkışma indeksi, temellerin tasarımında oturma hesapları için yaygın olarak kullanılan zeminlerin en önemli özelliklerinden biridir. Özellikle rutin deneyler, sınırlı laboratuvar koşulları ve ön değerlendirmeler için, literatürde zemin indeks özelliklerine bağlı olarak basitçe hesaplanabilen sıkışma indeksi denklemleri mevcuttur. Ancak, bu denklemler değişik verilerden oluşturulduğundan, çoğunlukla ilgilenilen bölge için sınırlı kullanım sunmaktadır. Bu yüzden, bölgeye ait yerel veriler ile (eğer veri mevcutsa) geliştirilen korelasyonları kullanmak en gerçekçi yoldur. Bu doğrultuda, bu çalışmada Bağdat şehrine ait ince daneli zeminler için, zemin indeks özelliklerinden doğal su muhtevası, likit limit ve başlangıç boşluk oranına bağlı olarak sıkışma indeksi denklemlerinin geliştirilmesi amaçlanmıştır. Elde edilen denklemlerden, sıkışma indeksinin tek değişkenli ilişkilerde likit limit ile, ve çok değişkenli ilişkilerde ise likit limit ve başlangıç boşluk oranı ile birlikte kullanıldığında en iyi korelasyonları verdiği bulunmuştır. Geliştirilen korelasyonların temel oturması için yapılacak ön değerlendirmelerde özellikle Bağdat bölgesi için kullanılmasının çok daha uygun olduğu açıktır.

Zemin Sıkışma İndeksi için Korelasyonların Geliştirilmesi

Compression index is one of the most important properties of soils widely used for estimation of settlement during design of foundations. In particular, for routine test requirements, limited laboratory facilities and preliminary evaluations, various equations are available in the literature to simply estimate the compression index using some soil index properties. However, applicability of these equations is often limited for the interested site due to their establishment from different databases. Thus, it is more realistic way to employ the correlations developed using local data of region, provided that data is available. In this viewpoint, this paper aims to develop correlations for the compression index dependent upon the soil index parameters of natural moisture content, liquid limit and initial void ratio for fine-grained soil of Baghdad city. From the developed correlations, it is obtained that the best estimations of compression index is correlated by liquid limit as single variable, and by liquid limit and initial void ratio as double variable. It is clear that use of the developed correlations is more suitable specifically for Baghdad region for preliminary evaluations of foundation settlement.

PDF

___

Alhashemy, A., 2015. Geotechnical Properties of Soil around Tigris River in Baghdad. M.Sc. Thesis, Department of Civil Engineering, University of Gaziantep, Gaziantep.
Al-Khafaji, A.W.N. and Andersland, O.B., 1992. Equations for compression index approximation. J Geotech Eng (ASCE), 118(1), 148-153.
ANDREA, 2016. Andrea Engineering Testing Laboratory. Baghdad, Iraq. http://andrealab.com/, Last Access on 25 March 2016.
ASTM D2435/D2435 M-11, 2011. Standard test methods for one dimensional consolidation properties of soils using incremental loading. ASTM D4186/D4186 M-12, 2012. Standard test method for one dimensional consolidation properties of saturated cohesive soils using controlled-strain loading.
Azzouz, A.S., Krizek, R.J. and Corotis, R.B., 1976. Regression analysis of soil compressibility. Soils Found, 16(2), 19-29.
Bowles, J.E., 1979. Physical and Geotechnical properties of Soils. McGraw-Hill Book Company, New York.
Burland, J.B., 1990. On the compressibility and shear strength of natural clays. Geotechnique, 40(3), 329- 378.
Cherubini, C. and Giasi, C.I., 2000. Correlation equations for normal consolidated clays. In: Yokohama IS, Nakase A, Tsuchida T (eds), Proc Int Symp on Coastal Geotechnical Engineering in Practice, AA Balkema, Rotterdam, pp.15-20.
Cherubini, C. and Orr, T.L.L., 2000. A rational procedure for comparing measured and calculated values in geotechnics. In: Yokohama, I.S., Nakase, A., Tsuchida, T. (eds), Proc Int Symp on Coastal Geotechnical Engineering in Practice, AA Balkema, Rotterdam, vol.1, pp 261-265.
Giasi, C.I., Cherubini, C. and Paccapelo, F., 2003. Evaluation of compression index of remolded clays by means of Atterberg limits. Bull Eng Geol Environ, 62(4), 333-340.
Hough, B.K., 1957. Basic Soils Engineering. The Ronald Press Company, New York, pp.114-115.
Lav, M.A.and Ansal, A.M., 2001. Regression analysis of soil compressibility. Turk J Engin Environ Sci, 25, 101 - 109.
Li, K.S. and White, W., 1993. Use and misuses of regression analysis and curve fitting in geotechnical engineering. In: Li KS, Lo SCR (eds), Probabilistic methods in geotechnical engineering, AA Balkema, Rotterdam, pp.145-152.
Onyejekwe, S., Xin Kang, X. and Ge, L., 2015. Assessment of empirical equations for the compression index of fine-grained soils in Missouri. Bull Eng Geol Environ, 74, 705-716.
Rendon-Herrero, O., 1983. Universal compression index equation. Closure. J Geotech Eng Div ASCE, 109(5), 755-761.
Skempton, A.W., 1944. Notes on the compressibility of clays. Quarterly Journal of Geological Society of London, 100, 119-135.
Sridharan, A. and Nagaraj, H.B., 2000. Compressibility behavior of remolded, fine-grained soils and correlation with index properties. Can Geotech J, 37, 712-722.
Sowers, G.B., 1970. Introductory Soil Mechanics and Foundations. 3rd edn. The Macmillan Company, Collier-Macmillan Limited, London, p102.
Terzaghi, K. and Peck, R.B., 1967. Soil Mechanics in Engineering Practice. 2nd Edition, John Wiley&Sons, New York, 729pp.
Tiwari, B. and Ajmera, B., 2012. New correlation equations for compression index of remolded clays. Technical Note. Journal of Geotechnical and Geoenvironmental Engineering, 138(6), 757-762.
Tsuchida, T., 1999. Unified model of e-log p relationship of clay and the interpretation of natural water content of marine deposits. In: Tsuchida T, Nakase IS (eds) Proc Int Symp on Characterization of Soft Marine Clays, AA Balkema, Rotterdam, pp185-202.