نوع مقاله : مقاله پژوهشی
نویسندگان
1 کارشناس ارشد مؤسسه تحقیقات خاک و آب
2 استادیار پژوهش مؤسسه تحقیقات خاک و آب
3 استادیار دانشگاه گیلان
4 کارشناس مؤسسه تحقیقات خاک و آب
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The (Atterberg) consistency limits of soil are important for soil mechanical properties the are used primarily in classifying cohesive soil materials for engineering purposes and are strongly correlated to other fundamental soil properties. They are also used for estimation of there useful indices for soil engineering interpretations, such as shear strength and bearing capacity, compressibility, swelling potential and specific surface. Whereas the direct measurement of there are time- consuming and require enough experiment, it is required that predict them indirectly by using some soil easily available properties with reasonable accuracy. The objective of this study was to predict soil liquid limit (LL), plastic limit (PL) and plasticity index (PI) indirectly from some easily available soil physical and chemical properties. In this research 37 loamy soil samples were randomly collected from karaj area 30 samples were used for model development and 7 samples were used for validation. Particle size distribution, bulk density, and cation exchange capacity were determined by the hydrometry, cold, and with ammonium acetate methods, respectively. Liquid limit were obtained using casagrande. The optimum combination of independent variables for estimation of LL, PL and PI were selected by using stepwise regression method. The regression equations were obtained using multiple linear regression method. The results indicated that there was a significant correlation between measured and predicted values. The correlation were significant at 0.1% for presented functions of liquid limit (R2 adj = 0.77), plastic limit (R2 adj = 0.72) and plasticity index (R2 adj = 0.62). Statistical analysis for the evaluation of PTFs indicated that Geometric mean error ratio (GMER) values were close to 1 (0.99-1.06) and Geometric standard deviation of the error ratio (GSDER) values were small (1.03 – 1.32). The results indicated that presented functions were valid.
کلیدواژهها [English]
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