Estimation of Strength Parameters of Saline Subgrade Stabilized by Cement and Industrial Waste Using Finite Element Method.

Saline soils are one of the types of problematic soils which are very vulnerable to dissolution and swelling phenomena. This type of soil has been observed in many parts of Iran and has been used as road subgrade. To enhance the resistance properties of salt beds, various methods are usually used, including chemical stabilization, and the geotechnical properties of stabilized salt beds are evaluated with field and laboratory tests. However, estimation of some main parameters' required for road design, such as modulus of resilience, is dependent on the use of three-dimensional cyclic tests, which requires spending considerable time and cost. This article's aim is to investigate the traffic loads effect on saline soil subgrade stabilized with cement and carbonated waste, by modeling the modulus of resilience parameter via finite elements method. The natural saline soil of this research was stabilized with different percentages of type 2 Portland cement and a type of carbonated waste, without treatment or treated with two different stabilization methods. Then, several resistance tests such as direct shear test, unconfined uniaxial compressive strength and California bearing ratio (CBR) were done on the samples. The obtained shear strength parameters were used in the modeling of the modulus of resilience. Considering the inherence of traffic loading and the type of test, after examining various soil constitutive models, the small strain hardening soil constitutive model was chosen for this analysis. After performing the modeling steps, including determining the model parameters, developing and running the model, analysis of the results showed that modulus of resilience has exponential relationship with the sum of the main axial and confining stresses. The model coefficients' relationship was determined and shown using multiple regression analyses. Also, the correlation between modulus of resilience and California bearing ration (CBR) are presented. [ABSTRACT FROM AUTHOR]

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